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diff --git a/3638/CH10/EX10.1/Ex10_1.jpg b/3638/CH10/EX10.1/Ex10_1.jpg
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diff --git a/3638/CH10/EX10.1/Ex10_1.sce b/3638/CH10/EX10.1/Ex10_1.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 10.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+n1=1.450840;//refractive index of core

+n2=1.446918;//refractive imdex of cladding

+a=4.1e-6;//radius of core in m

+n=2*%pi*a*sqrt((n1^2)-(n2^2))//numerator of the corresponding V number

+//corresponding V number expression where lambda0 is in nm

+mprintf("V=%.1f/lambda0",n*1e9);//multiplying numerator by 10^9 to convert lambda0 in nm

+//For cutoff wavelength:

+V=2.4048;

+//Since V=n/lambda0

+lambda0=n/V;//cutoff wavelength of single mode fiber in m

+mprintf("\n The cutoff wavelength is %.1f nm",lambda0/1e-9);//Division by 10^(-9) to convert into nm

diff --git a/3638/CH10/EX10.3/Ex10_3.jpg b/3638/CH10/EX10.3/Ex10_3.jpg
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diff --git a/3638/CH10/EX10.3/Ex10_3.sce b/3638/CH10/EX10.3/Ex10_3.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 10.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+n1=1.457893;//refractive index of core

+n2=1.446918;//refractive imdex of cladding

+a=2.3e-6;//radius of core in m

+delta=(n1-n2)/n2;//fractional change in refractive index

+mprintf("\n Delta=%f",delta);//The answers vary due to round off error

+n=2*%pi*a*sqrt((n1^2)-(n2^2))//numerator of the corresponding V number

+//corresponding V number expression where lambda0 is in nm

+mprintf("\n V=%.1f/lambda0",n*1e9);//multiplying numerator by 10^9 to convert lambda0 in nm

+//For cutoff wavelength:

+V=2.4048;

+//Since V=n/lambda0

+lambda0=n/V;//cutoff wavelength of single mode fiber in m

+mprintf("\n The cutoff wavelength is %.1f nm",lambda0/1e-9);//Division by 10^(-9) to convert into nm

diff --git a/3638/CH10/EX10.4/Ex10_4.jpg b/3638/CH10/EX10.4/Ex10_4.jpg
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diff --git a/3638/CH10/EX10.4/Ex10_4.sce b/3638/CH10/EX10.4/Ex10_4.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 10.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1550e-9;//operating wavelength of single mode fiber in m

+n1=1.476754;//refractive index of core

+n2=1.446918;//refractive imdex of cladding

+a=1.5e-6;//radius of core in m

+delta=(n1-n2)/n2;//fractional change in refractive index

+mprintf("\n Delta=%f",delta);//The answers vary due to round off error

+n=2*%pi*a*sqrt((n1^2)-(n2^2))//numerator of the corresponding V number

+//corresponding V number expression where lambda0 is in nm

+mprintf("\n V=%.1f/lambda0",n*1e9);//multiplying numerator by 10^9 to convert lambda0 in nm

+//For cutoff wavelength:

+V=2.4048;

+//Since V=n/lambda0

+lambda0=n/V;//cutoff wavelength of single mode fiber in m

+mprintf("\n The cutoff wavelength is %.1f nm",lambda0/1e-9);//Division by 10^(-9) to convert into nm

+//The answers vary due to round off error

diff --git a/3638/CH11/EX11.1/Ex11_1.jpg b/3638/CH11/EX11.1/Ex11_1.jpg
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diff --git a/3638/CH11/EX11.1/Ex11_1.sce b/3638/CH11/EX11.1/Ex11_1.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 11.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//E1 & E2 are the ground level and first excited level of energy respectively

+h=6.626e-34;//Planck's constant in SI Units

+c=3e8;//speed of electrons in m/s

+lambda=694e-9;//wavelength corresponding to the energy gap between E1 & E2

+//Let E2-E1=DeltaE

+DeltaE=h*c/lambda;

+mprintf("\n E2-E1=%e",DeltaE);//Energy gap between E1 & E2 in J

+//The answers vary due to round off error

+kB=1.38e-23;//Boltzmann constant in SI Units

+T=300;//Temperature in K

+mprintf("\n kB*T=%e",kB*T);

+//Let N2/N1 be N

+N=exp(-DeltaE/(kB*T));//Ratio of population density at E2 and E1 energy levels

+mprintf("\n N2/N1=%e",N);//The answers vary due to round off error

diff --git a/3638/CH11/EX11.2/Ex11_2.jpg b/3638/CH11/EX11.2/Ex11_2.jpg
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diff --git a/3638/CH11/EX11.2/Ex11_2.sce b/3638/CH11/EX11.2/Ex11_2.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 11.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//For Cr+3 ions in ruby

+N1=1.6e19;//Population density of E1 energy level in cm^(-3)

+N2=0;//Population density of E2 energy level in cm^(-3)

+n=1.76;//refractive index of medium

+Tsp=3e-3;//Spontaneous emission lifetime of atom in sec

+//Let g(v0) be g

+g=6.9e-12;//normalized lineshape function in s

+lambda0=694.3e-7;//wavelength at which absorption takes place in cm

+c=3e10;//speed of electrons in cm/s

+v=c/lambda0;

+//Let Y(v0) be Y

+Y=((c/n)^2)*g*(N2-N1)/(8*%pi*Tsp*(v^2));//Corresponding gain coefficient of medium

+mprintf("\n Absorption coefficient = %f",Y);//The answers vary due to round off error

+//negative sign implies absorption

diff --git a/3638/CH11/EX11.3/Ex11_3.jpg b/3638/CH11/EX11.3/Ex11_3.jpg
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index 000000000..e55326668
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diff --git a/3638/CH11/EX11.3/Ex11_3.sce b/3638/CH11/EX11.3/Ex11_3.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 11.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+R1=0.99;//reflection coefficient of mirror 1

+R2=0.9;//reflection coefficient of mirror 2

+l=10;//Distance between the two mirrors in cm

+alpha=0;//average loss coefficient per unit length of resonator in cm^(-1)

+Vth=alpha-log(R1*R2)/(2*l);//Corresponding threshold gain coefficient in cm^(-1)

+mprintf("\n The threshold gain coefficient = %e cm^-1",Vth);//The answers vary due to round off error

diff --git a/3638/CH11/EX11.4/Ex11_4.jpg b/3638/CH11/EX11.4/Ex11_4.jpg
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index 000000000..799cb1ef9
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diff --git a/3638/CH11/EX11.4/Ex11_4.sce b/3638/CH11/EX11.4/Ex11_4.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 11.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+R1=0.32;//reflection coefficient of mirror 1

+R2=0.32;//reflection coefficient of mirror 2

+l=300e-4;//Distance between the two mirrors in cm

+alpha=10;//average loss coefficient per unit length of resonator in cm^(-1)

+Vth=alpha-log(R1*R2)/(2*l);//Corresponding threshold gain coefficient in cm^(-1)

+mprintf("\n The threshold gain coefficient = %e cm^-1",Vth);//The answers vary due to round off error

diff --git a/3638/CH11/EX11.5/Ex11_5.jpg b/3638/CH11/EX11.5/Ex11_5.jpg
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index 000000000..7d17e207f
--- /dev/null
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diff --git a/3638/CH11/EX11.5/Ex11_5.sce b/3638/CH11/EX11.5/Ex11_5.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 11.5

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+R1=0.3;//reflection coefficient of mirror 1

+R2=0.3;//reflection coefficient of mirror 2

+l=500e-4;//Distance between the two mirrors in cm

+alpha=5e1;//average loss coefficient per unit length of resonator in cm^(-1)

+Vth=alpha-log(R1*R2)/(2*l);//Corresponding threshold gain coefficient in cm^(-1)

+mprintf("\n The threshold gain coefficient = %e cm^-1",Vth);//The answers vary due to round off error

diff --git a/3638/CH11/EX11.6/Ex11_6.jpg b/3638/CH11/EX11.6/Ex11_6.jpg
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index 000000000..98bcef740
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diff --git a/3638/CH11/EX11.6/Ex11_6.sce b/3638/CH11/EX11.6/Ex11_6.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 11.6

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given Case(i)

+lambdag=1.30e-6;//emission wavelength in m

+//Bandgap energy in eV is given by : 

+Eg=1.24/(lambdag/1e-6);//Division by 10^(-6) to convert lambdag into um

+mprintf("\nCase 1: for lambda0 =1.30 um");

+mprintf("\n Eg=%f eV",Eg);//The answers vary due to round off error

+p=[0.12 -0.72 1.35-Eg];//Relation between Eg & y is given as 'Eg(y)=1.35-0.72y+0.12y^2 in eV'

+y=roots(p);

+mprintf("\n y=%f",y(2,1));//Roots are arranged in descending order & y cannot be greater than 1

+//The answers vary due to round off error

+//given Case(ii)

+lambdag=1.55e-6;//emission wavelength in m

+//Bandgap energy in eV is given by : 

+Eg=1.24/(lambdag/1e-6);//Division by 10^(-6) to convert lambdag into um

+mprintf("\nCase 2: for lambda0 =1.55 um");

+mprintf("\n Eg=%f eV",Eg);//The answers vary due to round off error

+p=[0.12 -0.72 1.35-Eg];//Relation between Eg & y is given as 'Eg(y)=1.35-0.72y+0.12y^2 in eV'

+y=roots(p);

+mprintf("\n y=%f",y(2,1));//Roots are arranged in descending order & y cannot be greater than 1

+//The answers vary due to round off error

diff --git a/3638/CH12/EX12.1/Ex12_1.jpg b/3638/CH12/EX12.1/Ex12_1.jpg
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diff --git a/3638/CH12/EX12.1/Ex12_1.sce b/3638/CH12/EX12.1/Ex12_1.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 12.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda=0.8e-6;//wavelength of light in m

+n=3.5;//refractive index of Si

+e=1.6e-19;//electronic charge in C

+h=6.626e-34;//Planck's constant in SI Units

+c=3e8;//speed of electrons in m/s

+alpha=1e5;//average loss coefficient per unit length of resonator in m^(-1)

+w=20e-6;//width of depletion layer in m

+R=((n-1)/(n+1))^2;//Reflection coefficient of uncoated Si

+mprintf("\n R=%.2f",R);

+//Assuming all e-h pairs contribute to photo current i.e. zeta=1

+eta=(1-R)*(1-exp(-alpha*w));//Corresponding quantum efficiency

+mprintf("\n eta=%.1f",eta);

+v=c/lambda;//frequency corresponding to given wavelength in Hz

+rho=eta*e/(h*v);//corresponding responsivity in A/W

+mprintf("\n rho=%.2f A/W",rho);//The answers vary due to round off error

diff --git a/3638/CH12/EX12.2/Ex12_2.jpg b/3638/CH12/EX12.2/Ex12_2.jpg
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diff --git a/3638/CH12/EX12.2/Ex12_2.sce b/3638/CH12/EX12.2/Ex12_2.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 12.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given 

+rho=0.5;//responsitivity of Si PIN detector in A/W

+Vb=20;//reverse bias voltage across the detector in V

+//Case (i):

+Rl=100;//load resistor in ohms

+Pmax=Vb/(rho*Rl);//maximum value of optical power P falling on the photodetector in W

+mprintf("\n For Rl=100 Ohm:");

+mprintf("\n Pmax=%.1f mW",Pmax/1e-3)//Division by 10^(-3) to convert into mW

+mprintf("\n Vr/P = %.1f mV/mW",rho*Rl);//Bias voltage per unit power in mV/mW

+//Case (ii):

+Rl=10e3;//load resistor in ohms

+Pmax=Vb/(rho*Rl);//maximum value of optical power P falling on the photodetector in W

+mprintf("\n For Rl=10 kOhm:");

+mprintf("\n Pmax=%.1f mW",Pmax/1e-3)//Division by 10^(-3) to convert into mW

+//Bias voltage per unit power in V/mW :

+mprintf("\n Vr/P = %.1f V/mW",rho*Rl/1e3);//Division by 10^3 to convert into V/mW

diff --git a/3638/CH12/EX12.3/Ex12_3.jpg b/3638/CH12/EX12.3/Ex12_3.jpg
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index 000000000..9ebf4a4c8
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diff --git a/3638/CH12/EX12.3/Ex12_3.sce b/3638/CH12/EX12.3/Ex12_3.sce
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index 000000000..0c27c9d4a
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 12.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given 

+epsilon=10.5e-13;//permittivity of Si in F/cm

+d=500e-4;//diameter of Si detector in cm

+w=20e-4;//width of depletion layer in cm

+A=%pi*((d/2)^2);//Area of detector in cm^2

+Cd=epsilon*A/d;//Junction capacitance in F

+mprintf("\n The junction capacitance Cd=%f pF",Cd/1e-12);//division by 10^(-12) to convert into pF 

+//The answer provided in the textbook is wrong

diff --git a/3638/CH13/EX13.1/Ex13_1.jpg b/3638/CH13/EX13.1/Ex13_1.jpg
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diff --git a/3638/CH13/EX13.1/Ex13_1.sce b/3638/CH13/EX13.1/Ex13_1.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//Vc(t)=V0*(1-exp(-t/(R*C))) is the voltage across capacitance in an RC circuit

+//Hence, the time t=R*C*(-log(1-Vc/V0))

+

+//The Rise time is the time taken by a system to rise from 10% to 90% of maximum value

+//So, it is given as Tr=T90-T10 where T90 is time when Vc is 90% of maximum value and T10 is time when Vc is 10% of maximum value

+//i.e. Tr=R*C*(-log(1-0.9))-R*C*(-log(1-0.1))

+//Let Tr=R*C*k; where k=log(1-0.1))-log(1-0.9)

+k=log(1-0.1)-log(1-0.9);

+mprintf("\n The Rise Time Tr=%.2fRC",k);

+

+//Now, The 3dB bandwidth is given as Deltaf=1/(2*%pi*R*C);

+//Let Deltaf=m/(R*C); where m=1/(2*%pi)

+m=1/(2*%pi);

+mprintf("\n The 3dB bandwidth Deltaf=%.2f/RC",m);

+

+//By multiplying expressions of Tr and Deltaf, we eliminate RC from the expressions

+//Rearranging te terms, we get Tr in terms of Deltaf 

+mprintf("\n Rise time in terms of Bandwidth is given as:");

+mprintf("\n Tr=%.2f/Deltaf",k*m);

diff --git a/3638/CH13/EX13.10/Ex13_10.jpg b/3638/CH13/EX13.10/Ex13_10.jpg
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diff --git a/3638/CH13/EX13.10/Ex13_10.sce b/3638/CH13/EX13.10/Ex13_10.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.10

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+P=100e-9;//Optical power in W

+R=0.6;//Responsivity in A/W

+Rl=1000;//Value of load resistor in Ohms

+e=1.6e-19//Electronic charge in C

+kB=1.38e-23;//Boltzmann constant in SI Units

+T=300;//Missing data- Temperature in K

+x=0.7;//Excess noise

+Id=0;//Since the dark current is neglected in the example

+

+Mop=(4*kB*T/(x*e*Rl*(R*P+Id)))^(1/(x+2));//Optimum value of internal gain corresponding to input optical power P

+mprintf("Mop= %.1f",Mop);

diff --git a/3638/CH13/EX13.11/Ex13_11.jpg b/3638/CH13/EX13.11/Ex13_11.jpg
new file mode 100644
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diff --git a/3638/CH13/EX13.11/Ex13_11.sce b/3638/CH13/EX13.11/Ex13_11.sce
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.11

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+R=0.5;//Responsivity in A/W

+T=300;//Missing data- Temperature in K

+C=1e-12;//Photodiode capacitance in F

+BER=1e-9;//Bit error rate

+SNR=144;//Signal-to-noise ratio corresponding to BER of (10)^(-9)

+kB=1.38e-23;//Boltzmann constant in SI Units

+

+//Case(i):

+B=100e6;//Bit rate in b/s

+Pmin=B/R*sqrt(2*%pi*kB*T*C*SNR);

+mprintf("\n For 100 Mb/s, Pmin=%.2f uW",Pmin/1e-6);//Dividing by 10^(-6) to convert into uW

+

+//Case(ii):

+B=1e9;//Bit rate in b/s

+Pmin=B/R*sqrt(2*%pi*kB*T*C*SNR);

+mprintf("\n For 1 Gb/s, Pmin=%.2f uW",Pmin/1e-6);//Dividing by 10^(-6) to convert into uW

diff --git a/3638/CH13/EX13.12/Ex13_12.jpg b/3638/CH13/EX13.12/Ex13_12.jpg
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diff --git a/3638/CH13/EX13.12/Ex13_12.sce b/3638/CH13/EX13.12/Ex13_12.sce
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index 000000000..1f77ffaa4
--- /dev/null
+++ b/3638/CH13/EX13.12/Ex13_12.sce
@@ -0,0 +1,18 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.12

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+R=0.5;//Responsivity in A/W

+T=300;//Missing data- Temperature in K

+C=1e-12;//Photodiode capacitance in F

+BER=1e-6;//Bit error rate

+SNR=90;//Signal-to-noise ratio corresponding to BER of (10)^(-6)

+kB=1.38e-23;//Boltzmann constant in SI Units

+

+B=100e6;//Bit rate in b/s

+Pmin=B/R*sqrt(2*%pi*kB*T*C*SNR);

+mprintf("\n For 100 Mb/s, Pmin=%.2f uW",Pmin/1e-6);//Dividing by 10^(-6) to convert into uW

+//The answers vary due to round off error

diff --git a/3638/CH13/EX13.13/Ex13_13.jpg b/3638/CH13/EX13.13/Ex13_13.jpg
new file mode 100644
index 000000000..38f8ae7f6
--- /dev/null
+++ b/3638/CH13/EX13.13/Ex13_13.jpg
diff --git a/3638/CH13/EX13.13/Ex13_13.sce b/3638/CH13/EX13.13/Ex13_13.sce
new file mode 100644
index 000000000..4660ddd4a
--- /dev/null
+++ b/3638/CH13/EX13.13/Ex13_13.sce
@@ -0,0 +1,19 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.13

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+L=40;//Total fiber length in km

+alphat=0.5;//Fiber transmission loss in dB/km

+Pmin=-39;//Receiver sensitivity in dBm is the minimum power received by receiver

+Ns=4;//Number of splices contributing to loss

+Ls=0.5;//Loss of each splice in dB

+Nc=2;//Number of connectors contributing to loss

+Lc=1;//Loss of each connector in dB;

+Pm=6;//Power margin in dB

+//Let the source power be P

+P=Pmin+Pm+Ns*Ls+Nc*Lc+L*alphat;//Minimum value of source power in dBm

+mprintf("\n The source power must exceed %.2f dBm= %.2f mW",P,(10^(P/10)));//Taking 10^(P/10) to convert into mW

+

diff --git a/3638/CH13/EX13.14/Ex13_14.jpg b/3638/CH13/EX13.14/Ex13_14.jpg
new file mode 100644
index 000000000..7702fe8d6
--- /dev/null
+++ b/3638/CH13/EX13.14/Ex13_14.jpg
diff --git a/3638/CH13/EX13.14/Ex13_14.sce b/3638/CH13/EX13.14/Ex13_14.sce
new file mode 100644
index 000000000..d2b3ffa2e
--- /dev/null
+++ b/3638/CH13/EX13.14/Ex13_14.sce
@@ -0,0 +1,25 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.14

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+Pi=50e-6;//Source power in W

+R=0.65;//Responsivity in A/W

+T=300;//Missing data- Temperature in K

+C=5e-12;//Photodiode capacitance in F

+BER=1e-9;//Bit error rate

+SNR=144;//Signal-to-noise ratio corresponding to BER of (10)^(-6)

+kB=1.38e-23;//Boltzmann constant in SI Units

+

+B=20e6;//Bit rate in b/s

+Pmin=(B/R)*sqrt(2*%pi*kB*T*C*SNR);//Receiver sensitivity in W

+//Let the value of Pmin in dBm be denoted by 'PmindBm'

+PmindBm=10*log10(Pmin/1e-3);//Taking 10*log(Pmin) to convert into dBm where Pmin must be in mW

+mprintf("\n For 20 Mb/s, Pmin=%.2e W = %.1f dBm",Pmin,PmindBm);//The answers vary due to round off error

+//Let the value of Pi in dBm be denoted by 'PidBm'

+PidBm=10*log10(Pi/1e-3);//Taking 10*log(Pi) to convert into dBm where Pi must be in mW

+Pl=abs(PmindBm-PidBm);//The permissible loss between transmitter and receiver in dB

+mprintf("\n The permissible loss between transmitter and receiver = %.1f dB",Pl);

+//The answers vary due to round off error

diff --git a/3638/CH13/EX13.15/Ex13_15.jpg b/3638/CH13/EX13.15/Ex13_15.jpg
new file mode 100644
index 000000000..9928e8916
--- /dev/null
+++ b/3638/CH13/EX13.15/Ex13_15.jpg
diff --git a/3638/CH13/EX13.15/Ex13_15.sce b/3638/CH13/EX13.15/Ex13_15.sce
new file mode 100644
index 000000000..c1557ddcd
--- /dev/null
+++ b/3638/CH13/EX13.15/Ex13_15.sce
@@ -0,0 +1,14 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.15

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+B=400e6;//Bit rate in b/s

+BER=1e-9;//Bit error rate

+L=100;//Total fiber length in km

+

+//The Total system rise time is given as:

+Ts=0.7/B;//The expression for total rise time under NRZ transmission in s

+mprintf("\n The total system rise time Ts=%.2f ns",Ts/1e-9);//Dividing by 10^(-9) to convert into ns 

diff --git a/3638/CH13/EX13.16/Ex13_16.jpg b/3638/CH13/EX13.16/Ex13_16.jpg
new file mode 100644
index 000000000..ad519723e
--- /dev/null
+++ b/3638/CH13/EX13.16/Ex13_16.jpg
diff --git a/3638/CH13/EX13.16/Ex13_16.sce b/3638/CH13/EX13.16/Ex13_16.sce
new file mode 100644
index 000000000..ee202e679
--- /dev/null
+++ b/3638/CH13/EX13.16/Ex13_16.sce
@@ -0,0 +1,18 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.16

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda=1300e-9;//Operating wavekength of the system in m

+alpha=0.4;//Fiber loss in dB/km

+Pi=1e-3;//Input power in W

+Np=1000;//Minimum number of photons per bit of information

+B=2.5e9;//Bit rate in b/s

+h=6.63e-34;//Planck's constant in SI Units

+c=3e8;//Speed of photons in m/s

+v=c/lambda;//Frequency corresponding to the operating frequency

+

+Lmax=10/alpha*log10(2*Pi/(Np*B*h*v));//Maximum permissible loss-limited length in km

+mprintf("\n Maximum permissible loss-limited length Lmax=%.2f km",Lmax);//The answers vary due to round off error

diff --git a/3638/CH13/EX13.17/Ex13_17.jpg b/3638/CH13/EX13.17/Ex13_17.jpg
new file mode 100644
index 000000000..46f948a7d
--- /dev/null
+++ b/3638/CH13/EX13.17/Ex13_17.jpg
diff --git a/3638/CH13/EX13.17/Ex13_17.sce b/3638/CH13/EX13.17/Ex13_17.sce
new file mode 100644
index 000000000..040f657a3
--- /dev/null
+++ b/3638/CH13/EX13.17/Ex13_17.sce
@@ -0,0 +1,18 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.17

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda=1550e-9;//Operating wavekength of the system in m

+alpha=0.2;//Fiber loss in dB/km

+Pi=1e-3;//Input power in W

+Np=1000;//Minimum number of photons per bit of information

+B=2.5e9;//Bit rate in b/s

+h=6.63e-34;//Planck's constant in SI Units

+c=3e8;//Speed of photons in m/s

+v=c/lambda;//Frequency corresponding to the operating frequency

+

+Lmax=10/alpha*log10(2*Pi/(Np*B*h*v));//Maximum permissible loss-limited length in km

+mprintf("\n Maximum permissible loss-limited length Lmax=%.2f km",Lmax);//The answers vary due to round off error

diff --git a/3638/CH13/EX13.18/Ex13_18.jpg b/3638/CH13/EX13.18/Ex13_18.jpg
new file mode 100644
index 000000000..8321a9800
--- /dev/null
+++ b/3638/CH13/EX13.18/Ex13_18.jpg
diff --git a/3638/CH13/EX13.18/Ex13_18.sce b/3638/CH13/EX13.18/Ex13_18.sce
new file mode 100644
index 000000000..6058d92a5
--- /dev/null
+++ b/3638/CH13/EX13.18/Ex13_18.sce
@@ -0,0 +1,18 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.18

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda=850e-9;//Operating wavekength of the system in m

+alpha=2.5;//Fiber loss in dB/km

+Pi=1e-3;//Input power in W

+Np=1000;//Minimum number of photons per bit of information

+B=100e6;//Bit rate in b/s

+h=6.63e-34;//Planck's constant in SI Units

+c=3e8;//Speed of photons in m/s

+v=c/lambda;//Frequency corresponding to the operating frequency

+

+Lmax=10/alpha*log10(2*Pi/(Np*B*h*v));//Maximum permissible loss-limited length in km

+mprintf("\n Maximum permissible loss-limited length Lmax=%.2f km",Lmax);//The answers vary due to round off error

diff --git a/3638/CH13/EX13.2/Ex13_2.jpg b/3638/CH13/EX13.2/Ex13_2.jpg
new file mode 100644
index 000000000..715a31181
--- /dev/null
+++ b/3638/CH13/EX13.2/Ex13_2.jpg
diff --git a/3638/CH13/EX13.2/Ex13_2.sce b/3638/CH13/EX13.2/Ex13_2.sce
new file mode 100644
index 000000000..39df7da91
--- /dev/null
+++ b/3638/CH13/EX13.2/Ex13_2.sce
@@ -0,0 +1,11 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+B=2.5e9;//pulse rate of signal in bits/sec

+

+mprintf("\n In the RZ format, we would require a bandwidth = %.2f GHz",B/1e9);//In RZ format, Deltaf=B and Division by 10^9 to convert into GHz

+mprintf("\n In the NRZ format, we would require a bandwidth = %.2f GHz",(B/2)/1e9);//In RZ format, Deltaf=B/2 and Division by 10^9 to convert into GHz

diff --git a/3638/CH13/EX13.3/Ex13_3.jpg b/3638/CH13/EX13.3/Ex13_3.jpg
new file mode 100644
index 000000000..2511369d7
--- /dev/null
+++ b/3638/CH13/EX13.3/Ex13_3.jpg
diff --git a/3638/CH13/EX13.3/Ex13_3.sce b/3638/CH13/EX13.3/Ex13_3.sce
new file mode 100644
index 000000000..80c9fc3ec
--- /dev/null
+++ b/3638/CH13/EX13.3/Ex13_3.sce
@@ -0,0 +1,19 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+Id=1e-9;//Dark current of a silicon PIN photodiode in A

+P=1e-6;//Optical power in W

+R=0.65;//Responsivity in A/W

+e=1.6e-19//Electronic charge in C

+Deltaf=100e6;//Detector bandwidth in Hz

+

+I=R*P;

+mprintf("\n I=%.2f uA",I/1e-6)//Division by 10^(-6) to convert into uA

+//Let the root mean square shot noise current be Ins

+Ins=sqrt(2*e*(I+Id)*Deltaf);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot noise current = %.2f nA",Ins/1e-9);//Division by 10^(-9) to convert into nA

+//The answers vary due to round off error

diff --git a/3638/CH13/EX13.4/Ex13_4.jpg b/3638/CH13/EX13.4/Ex13_4.jpg
new file mode 100644
index 000000000..d95efac71
--- /dev/null
+++ b/3638/CH13/EX13.4/Ex13_4.jpg
diff --git a/3638/CH13/EX13.4/Ex13_4.sce b/3638/CH13/EX13.4/Ex13_4.sce
new file mode 100644
index 000000000..a003023f1
--- /dev/null
+++ b/3638/CH13/EX13.4/Ex13_4.sce
@@ -0,0 +1,16 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+Rl=500;//Value of load resistor Rl in Ohms

+kB=1.38e-23;//Boltzmann constant in SI Units

+Deltaf=100e6;//Bandwidth of detection in Hz

+T=300;//Temperature in K

+

+//Let the root mean square shot noise current be Ins

+Ins=sqrt(4*kB*T*Deltaf/Rl);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot noise current = %.2e A",Ins);

+mprintf("\n The mean square shot noise current = %.2e A^2",Ins^2)//The answers vary due to round off error

diff --git a/3638/CH13/EX13.5/Ex13_5.jpg b/3638/CH13/EX13.5/Ex13_5.jpg
new file mode 100644
index 000000000..4e21e1544
--- /dev/null
+++ b/3638/CH13/EX13.5/Ex13_5.jpg
diff --git a/3638/CH13/EX13.5/Ex13_5.sce b/3638/CH13/EX13.5/Ex13_5.sce
new file mode 100644
index 000000000..1e75b2ef2
--- /dev/null
+++ b/3638/CH13/EX13.5/Ex13_5.sce
@@ -0,0 +1,20 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.5

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+R=0.65;//Responsivity of a Si detector in A/W

+Id=1e-9;//Dark current in A

+e=1.6e-19;//Electronic charge in C

+kB=1.38e-23;//Boltzmann constant in SI Units

+Rl=1000;//Assumed value of load resistor Rl in Ohms

+T=300;//Assumed value of temperature in K

+

+NEP=1/R*sqrt(2*e*Id+4*kB*T/Rl);//Noise equivalent power in W/(Hz)^(1/2)

+mprintf("\n NEP = %.2e W/(Hz)^(1/2)",NEP);//The answers vary due to round off error

+//If Id is the major noise term :

+NEP=1/R*sqrt(2*e*Id);//Noise equivalent power in W/(Hz)^(1/2)

+mprintf("\n If Id is the major noise term:");

+mprintf("\n NEP = %.2e W/(Hz)^(1/2)",NEP);

diff --git a/3638/CH13/EX13.6/Ex13_6.jpg b/3638/CH13/EX13.6/Ex13_6.jpg
new file mode 100644
index 000000000..58b1d18bc
--- /dev/null
+++ b/3638/CH13/EX13.6/Ex13_6.jpg
diff --git a/3638/CH13/EX13.6/Ex13_6.sce b/3638/CH13/EX13.6/Ex13_6.sce
new file mode 100644
index 000000000..27102af8b
--- /dev/null
+++ b/3638/CH13/EX13.6/Ex13_6.sce
@@ -0,0 +1,36 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.6

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+Id=1e-9;//Dark current of a silicon PIN photodiode in A

+P=500e-9;//Optical power in W

+R=0.65;//Responsivity in A/W

+Rl=1000;//Value of load resistor in Ohms

+e=1.6e-19//Electronic charge in C

+kB=1.38e-23;//Boltzmann constant in SI Units

+Deltaf=100e6;//Detector bandwidth in Hz

+T=300;//Missing data- Temperature in K

+

+I=R*P;//Signal current in A

+mprintf("\n I=%.3f uA",I/1e-6)//Division by 10^(-6) to convert into uA

+//Let the root mean square shot noise current be Ins

+//The rms shot noise current due to signal is:

+Ins=sqrt(2*e*I*Deltaf);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot noise current due to signal = %.2f nA",Ins/1e-9);//Division by 10^(-9) to convert into nA

+//The answers vary due to round off error

+

+//The rms shot noise current due to dark current is:

+Ins=sqrt(2*e*Id*Deltaf);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot noise current due to dark current = %.2f nA",Ins/1e-9);//Division by 10^(-9) to convert into nA

+

+//The rms shot thermal noise current is:

+Ins=sqrt(4*kB*T*Deltaf/Rl);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot thermal noise current = %.2f nA",Ins/1e-9);//Division by 10^(-9) to convert into nA

+//The answers vary due to round off error

+SNR=((R*P)^2)*Rl/(4*kB*T*Deltaf);//Corresponding Signal-to-noise ratio

+mprintf("\n SNR = %f",SNR);//The answers vary due to round off error

+mprintf("\n SNR in dB = %f dB",10*log10(SNR));//For conversion to dB

+//The answers vary due to round off error

diff --git a/3638/CH13/EX13.7/Ex13_7.jpg b/3638/CH13/EX13.7/Ex13_7.jpg
new file mode 100644
index 000000000..8357283f1
--- /dev/null
+++ b/3638/CH13/EX13.7/Ex13_7.jpg
diff --git a/3638/CH13/EX13.7/Ex13_7.sce b/3638/CH13/EX13.7/Ex13_7.sce
new file mode 100644
index 000000000..cf6258c2a
--- /dev/null
+++ b/3638/CH13/EX13.7/Ex13_7.sce
@@ -0,0 +1,39 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.7

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+Id=1e-9;//Dark current of a silicon PIN photodiode in A

+P=500e-9;//Optical power in W

+R=0.65;//Responsivity in A/W

+Rl=1000;//Value of load resistor in Ohms

+e=1.6e-19//Electronic charge in C

+kB=1.38e-23;//Boltzmann constant in SI Units

+Deltaf=100e6;//Detector bandwidth in Hz

+T=300;//Missing data- Temperature in K

+M=50;//Internal gain corresponding to input optical power P

+x=0;//No excess noise

+

+I=M*R*P;//Signal current in A

+mprintf("\n I=%.2f uA",I/1e-6)//Division by 10^(-6) to convert into uA

+//Let the root mean square shot noise current be Ins

+//The rms shot noise current due to signal is:

+Ins=sqrt(2*e*M*I*Deltaf);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot noise current due to signal = %.2f nA",Ins/1e-9);//Division by 10^(-9) to convert into nA

+//The answers vary due to round off error

+

+//The rms shot noise current due to dark current is:

+Ins=sqrt(2*e*(M^2)*Id*Deltaf);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot noise current due to dark current = %.2f nA",Ins/1e-9);//Division by 10^(-9) to convert into nA

+//The answers vary due to round off error

+

+//The rms shot thermal noise current is:

+Ins=sqrt(4*kB*T*Deltaf/Rl);//As the root mean square shot noise current is the square root of mean square shot noise current in A

+mprintf("\n The rms shot thermal noise current = %.2f nA",Ins/1e-9);//Division by 10^(-9) to convert into nA

+//The answers vary due to round off error

+SNR=((M*R*P)^2)/(2*e*(M^(2+x))*(R*P+Id)*Deltaf+4*kB*T*Deltaf/Rl);//Corresponding Signal-to-noise ratio since x=0

+mprintf("\n SNR = %f",SNR);//The answers vary due to round off error

+mprintf("\n SNR in dB = %.2f dB",10*log10(SNR));//For conversion to dB

+//The answers vary due to round off error

diff --git a/3638/CH13/EX13.8/Ex13_8.jpg b/3638/CH13/EX13.8/Ex13_8.jpg
new file mode 100644
index 000000000..11d7dfca0
--- /dev/null
+++ b/3638/CH13/EX13.8/Ex13_8.jpg
diff --git a/3638/CH13/EX13.8/Ex13_8.sce b/3638/CH13/EX13.8/Ex13_8.sce
new file mode 100644
index 000000000..3eec3dea1
--- /dev/null
+++ b/3638/CH13/EX13.8/Ex13_8.sce
@@ -0,0 +1,31 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.8

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+P=100e-9;//Optical power in W

+R=0.65;//Responsivity in A/W

+Rl=1000;//Value of load resistor in Ohms

+e=1.6e-19//Electronic charge in C

+kB=1.38e-23;//Boltzmann constant in SI Units

+Deltaf=100e6;//Detector bandwidth in Hz

+T=300;//Missing data- Temperature in K

+x=0.3;//Excess noise

+Id=0;//Since the dark current is neglected in the example

+

+Mop=(4*kB*T/(x*e*Rl*(R*P+Id)))^(1/(x+2));//Optimum value of internal gain corresponding to input optical power P

+mprintf("Mop= %.1f",Mop);//The answers vary due to round off error

+SNR=((Mop*R*P)^2)/(2*e*(Mop^(2+x))*(R*P+Id)*Deltaf+4*kB*T*Deltaf/Rl);//Corresponding Signal-to-noise ratio since x=0

+mprintf("\n SNR = %f",SNR);//The answers vary due to round off error

+mprintf("\n SNR in dB = %.2f dB",10*log10(SNR));//For conversion to dB

+//The answers vary due to round off error

+

+//Case (ii):

+M=1;//Internal gain corresponding to input optical power P

+SNR=((M*R*P)^2)/(2*e*(M^(2+x))*(R*P+Id)*Deltaf+4*kB*T*Deltaf/Rl);//Corresponding Signal-to-noise ratio since x=0

+mprintf("\n For M=1:");

+mprintf("\n SNR = %f",SNR);//The answers vary due to round off error

+mprintf("\n SNR in dB = %.2f dB",10*log10(SNR));//For conversion to dB

+//The answers vary due to round off error

diff --git a/3638/CH13/EX13.9/Ex13_9.jpg b/3638/CH13/EX13.9/Ex13_9.jpg
new file mode 100644
index 000000000..9cbf1e4bf
--- /dev/null
+++ b/3638/CH13/EX13.9/Ex13_9.jpg
diff --git a/3638/CH13/EX13.9/Ex13_9.sce b/3638/CH13/EX13.9/Ex13_9.sce
new file mode 100644
index 000000000..f76e16086
--- /dev/null
+++ b/3638/CH13/EX13.9/Ex13_9.sce
@@ -0,0 +1,18 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 13.9

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+P=500e-9;//Optical power in W

+R=0.45;//Responsivity in A/W

+Rl=1000;//Value of load resistor in Ohms

+e=1.6e-19//Electronic charge in C

+kB=1.38e-23;//Boltzmann constant in SI Units

+T=300;//Missing data- Temperature in K

+x=1;//Excess noise

+Id=0;//Since the dark current is neglected in the example

+

+Mop=(4*kB*T/(x*e*Rl*(R*P+Id)))^(1/(x+2));//Optimum value of internal gain corresponding to input optical power P

+mprintf("Mop= %.1f",Mop);

diff --git a/3638/CH14/EX14.1/Ex14_1.jpg b/3638/CH14/EX14.1/Ex14_1.jpg
new file mode 100644
index 000000000..fc1c0c6d8
--- /dev/null
+++ b/3638/CH14/EX14.1/Ex14_1.jpg
diff --git a/3638/CH14/EX14.1/Ex14_1.sce b/3638/CH14/EX14.1/Ex14_1.sce
new file mode 100644
index 000000000..0fe0c0382
--- /dev/null
+++ b/3638/CH14/EX14.1/Ex14_1.sce
@@ -0,0 +1,45 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 14.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda=980e-9;//Operating wavelength in m

+Sigmapa=3.1e-25;//Absorption cross section at pump in m^2

+tsp=12e-3;//spontaneous emission lifetime in sec

+h=6.626e-34;//Planck's constant in SI Units

+c=3e8;//speed of electrons in m/s

+v=c/lambda;//frequency corresponding to given wavelength in Hz

+Ip0=h*v/(Sigmapa*tsp);//Intensity at pump in W/(m^2)

+mprintf("\n Ip0=%e W/(m^2)",Ip0)//The answers vary due to round off error

+

+//Case (i)

+lambdas=1536e-9;//Wavelength of signal used

+Sigmasa=4.644e-25;//Absorption cross section at signal in m^2

+Sigmase=4.644e-25;//Emission cross section at signal in m^2

+etas=Sigmase/Sigmasa;//Ratio of emission to absorption cross sections

+mprintf("\n\n For a signal wavelength of 1536 nm:");

+Ipt=Ip0/etas;//Threshold pump intensity in W/(m^2)

+mprintf("\n Threshold pump intensity = %.2e W/(m^2)",Ipt);//The answers vary due to round off error

+vs=c/lambdas;//frequency corresponding to wavelength of signal used

+Is0=h*vs/((Sigmasa+Sigmase)*tsp);//Corresponding intensity at signal in W/(m^2)

+mprintf("\n Is0=%.2e W/(m^2)",Is0);//The answers vary due to round off error

+

+//Case (ii)

+lambdas=1550e-9;//Wavelength of signal used

+Sigmasa=2.545e-25;//Absorption cross section at signal in m^2

+Sigmase=3.410e-25;//Emission cross section at signal in m^2

+etas=Sigmase/Sigmasa;//Ratio of emission to absorption cross sections

+mprintf("\n\n For a signal wavelength of 1550 nm:");

+Ipt=Ip0/etas;//Threshold pump intensity in W/(m^2)

+mprintf("\n Threshold pump intensity = %.2e W/(m^2)",Ipt);

+

+//Case (iii)

+lambdas=15380e-9;//Wavelength of signal used

+Sigmasa=0.654e-25;//Absorption cross section at signal in m^2

+Sigmase=1.133e-25;//Emission cross section at signal in m^2

+etas=Sigmase/Sigmasa;//Ratio of emission to absorption cross sections

+mprintf("\n\n For a signal wavelength of 1580 nm:");

+Ipt=Ip0/etas;//Threshold pump intensity in W/(m^2)

+mprintf("\n Threshold pump intensity = %.2e W/(m^2)",Ipt);

diff --git a/3638/CH14/EX14.4/Ex14_4.jpg b/3638/CH14/EX14.4/Ex14_4.jpg
new file mode 100644
index 000000000..87d5be332
--- /dev/null
+++ b/3638/CH14/EX14.4/Ex14_4.jpg
diff --git a/3638/CH14/EX14.4/Ex14_4.sce b/3638/CH14/EX14.4/Ex14_4.sce
new file mode 100644
index 000000000..d880380cf
--- /dev/null
+++ b/3638/CH14/EX14.4/Ex14_4.sce
@@ -0,0 +1,13 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 14.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+DeltaLambda0=30e-9;//Gain bandwidth in wavelength domain in m

+Lambda0=1550e-9;//central wavelength in wavelength domain in m

+c=3e8;//Speed of light in m/s

+v=c/Lambda0;

+Deltav=DeltaLambda0/Lambda0*v;

+mprintf("\n Gain Bandwidth in frequency domain = %.1f THz",Deltav/1e12); 

diff --git a/3638/CH17/EX17.1/Ex17_1.jpg b/3638/CH17/EX17.1/Ex17_1.jpg
new file mode 100644
index 000000000..75caf7041
--- /dev/null
+++ b/3638/CH17/EX17.1/Ex17_1.jpg
diff --git a/3638/CH17/EX17.1/Ex17_1.sce b/3638/CH17/EX17.1/Ex17_1.sce
new file mode 100644
index 000000000..7fa24ba5d
--- /dev/null
+++ b/3638/CH17/EX17.1/Ex17_1.sce
@@ -0,0 +1,45 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+n1=1.4532;//refractive index of core

+n2=1.45;//refractive index of cladding

+a=5e-6;//fiber core radius in m

+d=12e-6;//Distance between the fiber axes in m

+dbar=d/a;//Ratio of distance between fiber axes to the core radius

+delta=((n1)^2-(n2)^2)/((n1)^2);//Dimensionless quantity

+

+//Case (i):

+lambda0=1.3e-6;//Free space wavelength in m

+k0=2*%pi/lambda0;//free space wave number in rad/m

+V=k0*a*sqrt((n1^2)-(n2^2));//dimensionless waveguide parameter

+//The approximate expression for k consists of constants A, B and C

+A=5.2789-3.663*V+0.3841*(V^2);//Expression for constant A in terms of 'V'

+B=-0.7769+1.2252*V-0.0152*(V^2);//Expression for constant B in terms of 'V'

+C=-0.0175-0.0064*V-0.0009*(V^2);//Expression for constant C in terms of 'V'

+k=(%pi/(2*a))*sqrt(delta)*exp(-(A+B*dbar+C*(dbar)^2));//Expression for Coupling Coefficient in m^(-1)

+mprintf("\n For lambda=1.3 um:");

+mprintf("\n k=%f mm^(-1)",k/1e3);//Dividing by 10^3 to conevert into mm^(-1)

+//The answers vary due to round off error

+Lc=%pi/(2*k);//Corresponding coupling length in m

+mprintf("\n Lc =%.2f mm",Lc/1e-3);//Dividing by 10^(-3) to convert into mm

+P2=(sin(k*Lc/2))^2;//The coupled power at given wavelength

+mprintf("\n P2=%.2f",P2);

+

+//Case (ii):

+lambda0=1.35e-6;//Free space wavelength in m

+k0=2*%pi/lambda0;//free space wave number in rad/m

+V=k0*a*sqrt((n1^2)-(n2^2));//dimensionless waveguide parameter

+//The approximate expression for k consists of constants A, B and C

+A=5.2789-3.663*V+0.3841*(V^2);//Expression for constant A in terms of 'V'

+B=-0.7769+1.2252*V-0.0152*(V^2);//Expression for constant B in terms of 'V'

+C=-0.0175-0.0064*V-0.0009*(V^2);//Expression for constant C in terms of 'V'

+k=(%pi/(2*a))*sqrt(delta)*exp(-(A+B*dbar+C*(dbar)^2));//Expression for Coupling Coefficient in m^(-1)

+mprintf("\n For lambda=1.35 um:");

+mprintf("\n k=%f mm^(-1)",k/1e3);//Dividing by 10^3 to conevert into mm^(-1)

+//The answers vary due to round off error

+P2=(sin(k*Lc/2))^2;//The coupled power at given wavelength

+mprintf("\n P2=%.2f",P2);//The answers vary due to round off error

diff --git a/3638/CH17/EX17.2/Ex17_2.jpg b/3638/CH17/EX17.2/Ex17_2.jpg
new file mode 100644
index 000000000..f48f2b8d1
--- /dev/null
+++ b/3638/CH17/EX17.2/Ex17_2.jpg
diff --git a/3638/CH17/EX17.2/Ex17_2.sce b/3638/CH17/EX17.2/Ex17_2.sce
new file mode 100644
index 000000000..adb35ce8e
--- /dev/null
+++ b/3638/CH17/EX17.2/Ex17_2.sce
@@ -0,0 +1,13 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+b=62.5e-6;//Outer radius of silica fiber in m

+R=30e-3;//Radius of the circular loop formed by the fiber in m

+lambda=633e-9;//Wavelength in m

+C=0.133;//Value of constant C for a silica fiber at 633 nm

+Deltaneff=-C*(b/R)^2;//The Corresponding dimensionless birefringence

+mprintf("\n The birefringence of the given fiber = %.2e",Deltaneff);//The negative sign indicates that the polarization of the slow wave is perpendicular to the optic axis

diff --git a/3638/CH17/EX17.3/Ex17_3.jpg b/3638/CH17/EX17.3/Ex17_3.jpg
new file mode 100644
index 000000000..5c51c9e6f
--- /dev/null
+++ b/3638/CH17/EX17.3/Ex17_3.jpg
diff --git a/3638/CH17/EX17.3/Ex17_3.sce b/3638/CH17/EX17.3/Ex17_3.sce
new file mode 100644
index 000000000..1790eb175
--- /dev/null
+++ b/3638/CH17/EX17.3/Ex17_3.sce
@@ -0,0 +1,15 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=633e-9;//Wavelength in m

+b=62.5e-6;//Outer radius of silica fiber in m

+N=1;//Number of loops formed by the fiber

+C=0.133;//Value of constant C for a silica fiber at 633 nm

+

+R=8*%pi*C*(b^2)*N/lambda0;//Radius of the circular loop corresponding to a quarter plate formed by the fiber in m

+mprintf("\n R= %.2f cm",R/1e-2);//Division by 10^(-2) to convert into cm

+//The answers vary due to round off error

diff --git a/3638/CH17/EX17.4/Ex17_4.jpg b/3638/CH17/EX17.4/Ex17_4.jpg
new file mode 100644
index 000000000..1ee5811ba
--- /dev/null
+++ b/3638/CH17/EX17.4/Ex17_4.jpg
diff --git a/3638/CH17/EX17.4/Ex17_4.sce b/3638/CH17/EX17.4/Ex17_4.sce
new file mode 100644
index 000000000..6d076a109
--- /dev/null
+++ b/3638/CH17/EX17.4/Ex17_4.sce
@@ -0,0 +1,26 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+n2=1.45;//refractive imdex of cladding

+NA=0.1;//Numerical aperture of the fiber

+a=3e-6;//radius of core in m

+n=2*%pi*a*NA;//numerator of the corresponding V number

+

+//For cutoff wavelength:

+V=2.4048;

+//Since V=n/lambda0

+lambdac=n/V;//cutoff wavelength of single mode fiber in m

+mprintf("\n The cutoff wavelength is %.3f um",lambdac/1e-6);//Division by 10^(-6) to convert into um

+

+//Now, For lambdaB=850 nm:

+lambdaB=850e-9;//Bragg wavelength in m

+neff=1.4517;//Corresponding value of effective index in LP01 mode

+

+//Let A be grating period

+A=lambdaB/(2*neff);//Grating period in m

+mprintf("\n Grating period= %.3f um",A/1e-6);//Division by 10^(-6) to convert into um

+//The answers vary due to round off error

diff --git a/3638/CH17/EX17.5/Ex17_5.jpg b/3638/CH17/EX17.5/Ex17_5.jpg
new file mode 100644
index 000000000..2d9c99b20
--- /dev/null
+++ b/3638/CH17/EX17.5/Ex17_5.jpg
diff --git a/3638/CH17/EX17.5/Ex17_5.sce b/3638/CH17/EX17.5/Ex17_5.sce
new file mode 100644
index 000000000..682e5a5c8
--- /dev/null
+++ b/3638/CH17/EX17.5/Ex17_5.sce
@@ -0,0 +1,26 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.5

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//Since the reflectivity of fiber is 90%,

+R=0.9;//Reflection coefficient of fiber

+L=25e-3;//Length of fiber in m

+lambdaB=800e-9;//Bragg wavelength in m

+neff=1.4517;//Corresponding value of effective index in LP01 mode

+I=0.5;//Transverse overlap integral of modal distribution

+

+//Now, (tanh(k*L))^2=R

+//Rearranging terms, we get:

+k=atanh(sqrt(R))/L;//Corresponding coupling coefficient in m^(-1)

+mprintf("\n k=%.3f mm^(-1)",k/1e3);//Dividing by 10^3 to convert into mm^(-1)

+

+//Rearranging terms of expression k=%pi*Deltan*I/lambdaB

+Deltan=k*lambdaB/(%pi*I);//Change in refractive index

+mprintf("\n Deltan=%.2e",Deltan);//Unitless quantity

+//The answers vary due to round off error

+

+DeltaLambda=lambdaB^2/(%pi*neff*L)*sqrt((k*L)^2+(%pi)^2);//Corresponding bandwidth in m

+mprintf("\n DeltaLambda=%.2f nm",DeltaLambda/1e-9);//Division by 10^(-9) to convert into nm

diff --git a/3638/CH17/EX17.6/Ex17_6.jpg b/3638/CH17/EX17.6/Ex17_6.jpg
new file mode 100644
index 000000000..812b375a3
--- /dev/null
+++ b/3638/CH17/EX17.6/Ex17_6.jpg
diff --git a/3638/CH17/EX17.6/Ex17_6.sce b/3638/CH17/EX17.6/Ex17_6.sce
new file mode 100644
index 000000000..521c0b77e
--- /dev/null
+++ b/3638/CH17/EX17.6/Ex17_6.sce
@@ -0,0 +1,27 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.6

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//Since the reflectivity of fiber is 90%,

+R=0.9;//Reflection coefficient of fiber

+L=10e-3;//Length of fiber in m

+lambdaB=800e-9;//Bragg wavelength in m

+neff=1.4517;//Corresponding value of effective index in LP01 mode

+I=0.5;//Transverse overlap integral of modal distribution

+

+//Now, (tanh(k*L))^2=R

+//Rearranging terms, we get:

+k=atanh(sqrt(R))/L;//Corresponding coupling coefficient in m^(-1)

+mprintf("\n k=%.3f mm^(-1)",k/1e3);//Dividing by 10^3 to convert into mm^(-1)

+//The answers vary due to round off error

+

+//Rearranging terms of expression k=%pi*Deltan*I/lambdaB

+Deltan=k*lambdaB/(%pi*I);//Change in refractive index

+mprintf("\n Deltan=%.2e",Deltan);//Unitless quantity

+//The answers vary due to round off error

+

+DeltaLambda=lambdaB^2/(%pi*neff*L)*sqrt((k*L)^2+(%pi)^2);//Corresponding bandwidth in m

+mprintf("\n DeltaLambda=%.2f nm",DeltaLambda/1e-9);//Division by 10^(-9) to convert into nm

diff --git a/3638/CH17/EX17.7/Ex17_7.jpg b/3638/CH17/EX17.7/Ex17_7.jpg
new file mode 100644
index 000000000..815d00906
--- /dev/null
+++ b/3638/CH17/EX17.7/Ex17_7.jpg
diff --git a/3638/CH17/EX17.7/Ex17_7.sce b/3638/CH17/EX17.7/Ex17_7.sce
new file mode 100644
index 000000000..7ce8f9574
--- /dev/null
+++ b/3638/CH17/EX17.7/Ex17_7.sce
@@ -0,0 +1,27 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.7

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//Since the peak reflectivity of fiber is 0.93%,

+R=0.93;//Reflection coefficient of fiber

+L=4.8e-3;//Length of fiber in m

+lambdaB=1532.1e-9;//Bragg wavelength in m

+neff=1.4517;//Corresponding value of effective index in LP01 mode

+I=0.5;//Transverse overlap integral of modal distribution

+

+//Now, (tanh(k*L))^2=R

+//Rearranging terms, we get:

+k=atanh(sqrt(R))/L;//Corresponding coupling coefficient in m^(-1)

+mprintf("\n k=%.3f mm^(-1)",k/1e3);//Dividing by 10^3 to convert into mm^(-1)

+//The answers vary due to round off error

+

+//Rearranging terms of expression k=%pi*Deltan*I/lambdaB

+Deltaneff=k*lambdaB/(%pi);//Change in effective refractive index

+mprintf("\n Deltaneff=%.2e",Deltaneff);//Unitless quantity

+//The answers vary due to round off error

+

+DeltaLambda=lambdaB^2/(%pi*neff*L)*sqrt((k*L)^2+(%pi)^2);//Corresponding bandwidth in m

+mprintf("\n DeltaLambda=%.2f nm",DeltaLambda/1e-9);//Division by 10^(-9) to convert into nm

diff --git a/3638/CH17/EX17.8/Ex17_8.jpg b/3638/CH17/EX17.8/Ex17_8.jpg
new file mode 100644
index 000000000..c36e204a0
--- /dev/null
+++ b/3638/CH17/EX17.8/Ex17_8.jpg
diff --git a/3638/CH17/EX17.8/Ex17_8.sce b/3638/CH17/EX17.8/Ex17_8.sce
new file mode 100644
index 000000000..a302e2e82
--- /dev/null
+++ b/3638/CH17/EX17.8/Ex17_8.sce
@@ -0,0 +1,30 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.8

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//Since the reflectivity of fiber is 99%,

+R=0.99;//Reflection coefficient of fiber

+lambdaB=1550e-9;//Bragg wavelength in m

+neff=1.45;//Corresponding value of effective index in LP01 mode

+DeltaLambda=1e-9;//Bandwidth of reflection spectrum in m

+I=0.75;//Typical value of transverse overlap integral of modal distribution

+

+//Now, (tanh(k*L))^2=R

+//Rearranging terms, we get:  k*L=atanh(sqrt(R))

+//Let m=k*L

+m=atanh(sqrt(R));

+

+//Rearranging terms of expression DeltaLambda=lambdaB^2/(%pi*neff*L)*sqrt((k*L)^2+(%pi)^2) , we get

+L=lambdaB^2/(%pi*neff*DeltaLambda)*sqrt(m^2+(%pi)^2)//Since m=k*L

+//Length of fiber in m

+mprintf("\n L=%.2f mm",L/1e-3);//Division by 10^(-3) to convert into mm

+

+//Rearranging terms of m=k*L, we get:

+k=m/L;//Corresponding coupling coefficient in m^(-1)

+

+//Rearranging terms of expression k=%pi*Deltan*I/lambdaB

+Deltan=k*lambdaB/(%pi*I);//Change in refractive index

+mprintf("\n Deltan=%.2e",Deltan);//Unitless quantity

diff --git a/3638/CH17/EX17.9/Ex17_9.jpg b/3638/CH17/EX17.9/Ex17_9.jpg
new file mode 100644
index 000000000..bab197c7f
--- /dev/null
+++ b/3638/CH17/EX17.9/Ex17_9.jpg
diff --git a/3638/CH17/EX17.9/Ex17_9.sce b/3638/CH17/EX17.9/Ex17_9.sce
new file mode 100644
index 000000000..5892a8980
--- /dev/null
+++ b/3638/CH17/EX17.9/Ex17_9.sce
@@ -0,0 +1,22 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 17.9

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+a=5e-6;//Fiber core radius in m

+NA=0.09;//Numerical aperture of the fiber

+lambda0=1.3e-6;//Wavelength of radiation to be reflected from a Bragg grating

+

+V=2*%pi*a*NA/lambda0;//Corrseponding dimensionless V number

+mprintf("\n V=%f",V);//The answers vary due to round off error

+

+//Since W0=(0.65+1.619/V^(3/2)+2.879/V^6)*a ,  where W0 is the mode spot size in m

+//Let W0=m*a , where m=0.65+1.619/V^(3/2)+2.879/V^6

+m=0.65+1.619/V^(3/2)+2.879/V^6;

+mprintf("\n W0/a=%f",m);//The answers vary due to round off error

+

+//Given that I=1-exp(-2*(a/W0)^2);

+I=1-exp(-2/m^2);//From the assumption that m=W0/a

+mprintf("\n I=%.2f",I);

diff --git a/3638/CH18/EX18.1/Ex18_1.jpg b/3638/CH18/EX18.1/Ex18_1.jpg
new file mode 100644
index 000000000..990f37f53
--- /dev/null
+++ b/3638/CH18/EX18.1/Ex18_1.jpg
diff --git a/3638/CH18/EX18.1/Ex18_1.sce b/3638/CH18/EX18.1/Ex18_1.sce
new file mode 100644
index 000000000..a9aed2f82
--- /dev/null
+++ b/3638/CH18/EX18.1/Ex18_1.sce
@@ -0,0 +1,13 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 18.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=0.633e-6;//Operating wavelength in m

+DeltaPhi=1e-6;//Phase change in rad

+n=1.45;//refractive index of fiber

+

+DeltaL=DeltaPhi/(2*%pi*n/lambda0);//Corresponding change in fiber length in m

+mprintf("\n Corresponding change in fiber length = %.2e m",DeltaL);//The answers vary due to round off error

diff --git a/3638/CH18/EX18.2/Ex18_2.jpg b/3638/CH18/EX18.2/Ex18_2.jpg
new file mode 100644
index 000000000..56b38a84a
--- /dev/null
+++ b/3638/CH18/EX18.2/Ex18_2.jpg
diff --git a/3638/CH18/EX18.2/Ex18_2.sce b/3638/CH18/EX18.2/Ex18_2.sce
new file mode 100644
index 000000000..10db65651
--- /dev/null
+++ b/3638/CH18/EX18.2/Ex18_2.sce
@@ -0,0 +1,14 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 18.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+SPL=20;//Sound Pressure Level of a whisper in dB

+Pr=2e-5;//Reference pressure is the threshold of hearing in Pa

+

+//Now, SPL=20log10(Pw/Pr)

+//Rearranging the terms, we get

+Pw=10^(SPL/20)*Pr;

+mprintf("\n Pw=%.1e Pa",Pw); 

diff --git a/3638/CH18/EX18.3/Ex18_3.jpg b/3638/CH18/EX18.3/Ex18_3.jpg
new file mode 100644
index 000000000..9aa0dcc80
--- /dev/null
+++ b/3638/CH18/EX18.3/Ex18_3.jpg
diff --git a/3638/CH18/EX18.3/Ex18_3.sce b/3638/CH18/EX18.3/Ex18_3.sce
new file mode 100644
index 000000000..be96f1e77
--- /dev/null
+++ b/3638/CH18/EX18.3/Ex18_3.sce
@@ -0,0 +1,13 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 18.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+L=100;//Length of sensing element in m

+DeltaP=2e-5;//Threshold of hearing in Pa

+S=3.4e-4;//Sensitivity of element in rad/Pa/m

+

+DeltaPhi=S*DeltaP*L;//Corresponding change in phase in rad

+mprintf("\n DeltaPhi=%.1e rad",DeltaPhi);

diff --git a/3638/CH18/EX18.4/Ex18_4.jpg b/3638/CH18/EX18.4/Ex18_4.jpg
new file mode 100644
index 000000000..7ea3b6368
--- /dev/null
+++ b/3638/CH18/EX18.4/Ex18_4.jpg
diff --git a/3638/CH18/EX18.4/Ex18_4.sce b/3638/CH18/EX18.4/Ex18_4.sce
new file mode 100644
index 000000000..73fb8a631
--- /dev/null
+++ b/3638/CH18/EX18.4/Ex18_4.sce
@@ -0,0 +1,13 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 18.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+S=3.4e-4;//Sensitivity of the sensing element in rad/Pa/m

+DeltaMin=3.6e-8;//Minimum detectable phase change in rad

+L=1;//Length of sensing element in m

+

+Pmin=DeltaMin/(L*S);//Corresponding minimum detectable pressure in Pa

+mprintf("\n Pmin= %.1e Pa",Pmin);//The answers vary due to round off error

diff --git a/3638/CH18/EX18.5/Ex18_5.jpg b/3638/CH18/EX18.5/Ex18_5.jpg
new file mode 100644
index 000000000..d73fc4ee7
--- /dev/null
+++ b/3638/CH18/EX18.5/Ex18_5.jpg
diff --git a/3638/CH18/EX18.5/Ex18_5.sce b/3638/CH18/EX18.5/Ex18_5.sce
new file mode 100644
index 000000000..b1d849bf0
--- /dev/null
+++ b/3638/CH18/EX18.5/Ex18_5.sce
@@ -0,0 +1,13 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 18.5

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+V=2.64e-4;//Verdet constant for silica in deg/A

+N=30;//Number of turns of fiber

+I=1;//Current through the fiber in A

+

+Theta=V*N*I;//Corresponding rotation of plane of polarization in deg

+mprintf("\n Theta= %.2e deg",Theta);

diff --git a/3638/CH18/EX18.6/Ex18_6.jpg b/3638/CH18/EX18.6/Ex18_6.jpg
new file mode 100644
index 000000000..1212a9d8b
--- /dev/null
+++ b/3638/CH18/EX18.6/Ex18_6.jpg
diff --git a/3638/CH18/EX18.6/Ex18_6.sce b/3638/CH18/EX18.6/Ex18_6.sce
new file mode 100644
index 000000000..407338883
--- /dev/null
+++ b/3638/CH18/EX18.6/Ex18_6.sce
@@ -0,0 +1,20 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 18.6

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+b=62.5e-6;//Fiber radius in m

+R=20e-2;//Loop radius in m

+lambda0=633e-9;//Wavelength in m

+C=0.133;//Value of constant C for a silica fiber at 633 nm

+V=4.6e-6;//Verdet constant for silica in rad/A

+N=30;//Number of turns of fiber

+I=1;//Current through the fiber in A

+

+Delta=((2*%pi)^2)*R*N*(-C*(b/R)^2)/lambda0;//The Corresponding dimensionless birefringence

+mprintf("\n Delta= %.2f rad",Delta);//The negative sign indicates that the polarization of the slow wave is perpendicular to the optic axis

+

+Theta=V*N*I;//Corresponding rotation of plane of polarization in rad

+mprintf("\n Theta= %.2e rad",Theta);//The answers vary due to round off error

diff --git a/3638/CH2/EX2.1/Ex2_1.jpg b/3638/CH2/EX2.1/Ex2_1.jpg
new file mode 100644
index 000000000..fcaf4dc89
--- /dev/null
+++ b/3638/CH2/EX2.1/Ex2_1.jpg
diff --git a/3638/CH2/EX2.1/Ex2_1.sce b/3638/CH2/EX2.1/Ex2_1.sce
new file mode 100644
index 000000000..80497f19a
--- /dev/null
+++ b/3638/CH2/EX2.1/Ex2_1.sce
@@ -0,0 +1,15 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given 

+P=1e-3;//power of laser beam in W

+A=3e-6;//cross-sectional area of laser beam in m^2

+I=P/A;//power per unit area of laser beam in W/m^2

+n=1;//refractive index of air medium

+c=3e8;//speed of light in air medium in m/s

+meu0=4*(%pi)*1e-7;//permeability of free space in SI units

+E0=sqrt(2*c*meu0*I/n)//Corresponding electric field in V/m

+mprintf("Electric field=%.1f V/m",E0);//The answers vary due to round off error

diff --git a/3638/CH2/EX2.2/Ex2_2.jpg b/3638/CH2/EX2.2/Ex2_2.jpg
new file mode 100644
index 000000000..574dfc423
--- /dev/null
+++ b/3638/CH2/EX2.2/Ex2_2.jpg
diff --git a/3638/CH2/EX2.2/Ex2_2.sce b/3638/CH2/EX2.2/Ex2_2.sce
new file mode 100644
index 000000000..690ac63a0
--- /dev/null
+++ b/3638/CH2/EX2.2/Ex2_2.sce
@@ -0,0 +1,15 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given 

+P=10;//power of bulb in W

+A=4*%pi*1e2;//cross-sectional area covered by bulb in m^2

+I=P/A;//power per unit area of bulb in W/m^2

+n=1;//refractive index of air medium

+c=3e8;//speed of light in air medium in m/s

+meu0=4*(%pi)*1e-7;//permeability of free space in SI units

+E0=sqrt(2*c*meu0*I/n)//Corresponding electric field in V/m

+mprintf("Electric field=%.1f V/m",E0);//Final answer

diff --git a/3638/CH2/EX2.3/Ex2_3.jpg b/3638/CH2/EX2.3/Ex2_3.jpg
new file mode 100644
index 000000000..2288ecbc8
--- /dev/null
+++ b/3638/CH2/EX2.3/Ex2_3.jpg
diff --git a/3638/CH2/EX2.3/Ex2_3.sce b/3638/CH2/EX2.3/Ex2_3.sce
new file mode 100644
index 000000000..04e86cc87
--- /dev/null
+++ b/3638/CH2/EX2.3/Ex2_3.sce
@@ -0,0 +1,15 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given 

+P=1e-3;//power of laser beam in W

+A=%pi*(6e-6)^2;//cross-sectional area of spot of laser beam in m^2

+I=P/A;//power per unit area of laser beam in W/m^2

+n=1;//refractive index of air medium

+c=3e8;//speed of light in air medium in m/s

+meu0=4*(%pi)*1e-7;//permeability of free space in SI units

+E0=sqrt(2*c*meu0*I/n)//Corresponding electric field in V/m

+mprintf("Electric field=%.1e V/m",E0);//The answers vary due to round off error

diff --git a/3638/CH2/EX2.4/Ex2_4.jpg b/3638/CH2/EX2.4/Ex2_4.jpg
new file mode 100644
index 000000000..282cd8905
--- /dev/null
+++ b/3638/CH2/EX2.4/Ex2_4.jpg
diff --git a/3638/CH2/EX2.4/Ex2_4.sce b/3638/CH2/EX2.4/Ex2_4.sce
new file mode 100644
index 000000000..7635c0ab8
--- /dev/null
+++ b/3638/CH2/EX2.4/Ex2_4.sce
@@ -0,0 +1,16 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given Case(1)

+n1=1;//refractive index of air

+n2=1.45;//refractive index of silica

+R=[(n1-n2)/(n1+n2)]^2;//corresponding energy reflection coefficient

+mprintf("Energy reflection coefficient for air-silica interface=%.2f",R);

+//given Case(2)

+n1=1;//refractive index of air

+n2=3.6;//refractive index of GaAs

+R=[(n1-n2)/(n1+n2)]^2;//corresponding energy reflection coefficient

+mprintf("\n Energy reflection coefficient for GaAs-air interface=%.2f",R);

diff --git a/3638/CH2/EX2.5/Ex2_5.jpg b/3638/CH2/EX2.5/Ex2_5.jpg
new file mode 100644
index 000000000..c310e887b
--- /dev/null
+++ b/3638/CH2/EX2.5/Ex2_5.jpg
diff --git a/3638/CH2/EX2.5/Ex2_5.sce b/3638/CH2/EX2.5/Ex2_5.sce
new file mode 100644
index 000000000..bff5a8dc1
--- /dev/null
+++ b/3638/CH2/EX2.5/Ex2_5.sce
@@ -0,0 +1,12 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.5

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+n1=1.45;//refractive index of silica

+n2=1;//refractive index of air

+thetac=asin(n2/n1);//critical angle for the air-silica interface in radians

+mprintf("Critical angle for air-silica interface=%.1f degrees",thetac*180/%pi);//multiplying by 180/pi to convert radians to degrees

+

diff --git a/3638/CH2/EX2.6/Ex2_6.jpg b/3638/CH2/EX2.6/Ex2_6.jpg
new file mode 100644
index 000000000..46a60a0fd
--- /dev/null
+++ b/3638/CH2/EX2.6/Ex2_6.jpg
diff --git a/3638/CH2/EX2.6/Ex2_6.sce b/3638/CH2/EX2.6/Ex2_6.sce
new file mode 100644
index 000000000..b7e9b14db
--- /dev/null
+++ b/3638/CH2/EX2.6/Ex2_6.sce
@@ -0,0 +1,11 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.6

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+n1=1.46;//refractive index of doped silica

+n2=1.45;//refractive index of pure silica

+thetac=asin(n2/n1);//critical angle for interface between doped silica and pure silica in radians

+mprintf("Critical angle for interface between doped silica and pure silica=%.1f degrees",thetac*180/%pi);//multiplying by 180/pi to convert radians to degrees

diff --git a/3638/CH2/EX2.7/Ex2_7.jpg b/3638/CH2/EX2.7/Ex2_7.jpg
new file mode 100644
index 000000000..25c7d52d2
--- /dev/null
+++ b/3638/CH2/EX2.7/Ex2_7.jpg
diff --git a/3638/CH2/EX2.7/Ex2_7.sce b/3638/CH2/EX2.7/Ex2_7.sce
new file mode 100644
index 000000000..8fd1649b4
--- /dev/null
+++ b/3638/CH2/EX2.7/Ex2_7.sce
@@ -0,0 +1,17 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.7

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given Case(1)

+lambda=850e-9;//wavelength of LED in m

+deltalambda=30e-9;//spacing between wavelengths in m

+lc=(lambda)^2/deltalambda;//Corresponding coherence length

+mprintf("Coherence length of LED=%.1f um",lc/1e-6);//Dividing by 10^(-6) to convert in micrometers

+//The answers vary due to round off error

+//given Case(2)

+lambda=850e-9;//wavelength of laser diode in m

+deltalambda=2e-9;//spacing between wavelengths in m

+lc=(lambda)^2/deltalambda;//Corresponding coherence length

+mprintf("\n Coherence length of laser diode=%.2f mm",lc/1e-3);//Dividing by 10^(-3) to convert in millimeters

diff --git a/3638/CH2/EX2.8/Ex2_8.jpg b/3638/CH2/EX2.8/Ex2_8.jpg
new file mode 100644
index 000000000..07f0c9f33
--- /dev/null
+++ b/3638/CH2/EX2.8/Ex2_8.jpg
diff --git a/3638/CH2/EX2.8/Ex2_8.sce b/3638/CH2/EX2.8/Ex2_8.sce
new file mode 100644
index 000000000..92bf2906a
--- /dev/null
+++ b/3638/CH2/EX2.8/Ex2_8.sce
@@ -0,0 +1,11 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.8

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+deltanu=1.5e9;//change in frequency of He-Ne laser in Hz

+c=3e8;//speed of light in m/s

+lc=c/deltanu;//Corresponding coherence length

+mprintf("Coherence length of He-Ne laser=%.1f cm",lc/1e-2);//Dividing by 10^(-2) to convert in cm

diff --git a/3638/CH2/EX2.9/Ex2_9.jpg b/3638/CH2/EX2.9/Ex2_9.jpg
new file mode 100644
index 000000000..b0519bb57
--- /dev/null
+++ b/3638/CH2/EX2.9/Ex2_9.jpg
diff --git a/3638/CH2/EX2.9/Ex2_9.sce b/3638/CH2/EX2.9/Ex2_9.sce
new file mode 100644
index 000000000..92b447ef5
--- /dev/null
+++ b/3638/CH2/EX2.9/Ex2_9.sce
@@ -0,0 +1,11 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 2.9

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1300e-9;//wavelength of single-mode fiber in m

+omega0=5e-6;//spot size of beam in m

+theta=atan(lambda0/(%pi*omega0));//Corresponding divergence in radians

+mprintf("Divergence of beam=%.2f degrees",theta*180/%pi);//multiplying by 180/pi to convert radians to degrees

diff --git a/3638/CH21/EX21.1/Ex21_1.jpg b/3638/CH21/EX21.1/Ex21_1.jpg
new file mode 100644
index 000000000..8b74a51da
--- /dev/null
+++ b/3638/CH21/EX21.1/Ex21_1.jpg
diff --git a/3638/CH21/EX21.1/Ex21_1.sce b/3638/CH21/EX21.1/Ex21_1.sce
new file mode 100644
index 000000000..6ceed3ddc
--- /dev/null
+++ b/3638/CH21/EX21.1/Ex21_1.sce
@@ -0,0 +1,31 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+nf=1.51;//refractive index of film

+ns=1.50;//refractive index of substrate

+nc=1.0;//refractive index of cover

+d=4e-6;//thickness of film in m

+lambda0=0.6e-6;//Wavelength in m

+ne1=1.50862;//Corresponding effective refractive index for core

+ne2=1.5046;//Corresponding effective refractive index for cladding

+k0=2*(%pi)/lambda0;//free space wave number in rad/m

+//Let A be the period of perturbation in m

+

+A=lambda0/(ne1-ne2);

+mprintf("\n A= %.1f um",A/1e-6);//Division by 10^(-6) to convert into um

+

+d1=d+1/(k0*sqrt(ne1^2-ns^2))+1/(k0*sqrt(ne1^2-nc^2));//Effective waveguide thickness for mode 1 in m

+mprintf("\n d1= %.3f um",d1/1e-6);//Division by 10^(-6) to convert into um

+d2=d+1/(k0*sqrt(ne2^2-ns^2))+1/(k0*sqrt(ne2^2-nc^2));//Effective waveguide thickness for mode 2 in m

+mprintf("\n d2= %.3f um",d2/1e-6);//Division by 10^(-6) to convert into um

+//Assuming h=0.01um in expression for k, we get:

+k=%pi/lambda0*0.01e-6*sqrt(((nf^2-ne1^2)*(nf^2-nc^2))/d1*d2*ne1*ne2);//Coupling coefficient in m^-1

+mprintf("\n k=%.3f cm^(-1)",k*1e2);//Multiplying by 10^2 to convert into cm^(-1)

+//The answers vary due to round off error

+L=%pi/(2*k);//Length for complete power transfer in m

+mprintf("\n L=%.2f cm",L/1e2);//Division by 10^2 to convert into cm

+//The answers vary due to round off error

diff --git a/3638/CH21/EX21.2/Ex21_2.jpg b/3638/CH21/EX21.2/Ex21_2.jpg
new file mode 100644
index 000000000..9f5edd149
--- /dev/null
+++ b/3638/CH21/EX21.2/Ex21_2.jpg
diff --git a/3638/CH21/EX21.2/Ex21_2.sce b/3638/CH21/EX21.2/Ex21_2.sce
new file mode 100644
index 000000000..2539437db
--- /dev/null
+++ b/3638/CH21/EX21.2/Ex21_2.sce
@@ -0,0 +1,45 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+nf=1.51;//refractive index of film

+ns=1.50;//refractive index of substrate

+nc=1.0;//refractive index of cover

+d=4e-6;//thickness of film in m

+lambda0=0.6e-6;//Wavelength in m

+ne1=1.50862;//Corresponding effective refractive index for core

+ne2=1.5046;//Corresponding effective refractive index for cladding

+//Let A be the period of perturbation in m

+

+

+//Case (i):

+A=100e-6;

+K=2*%pi/A;

+k=0.598e2;//coupling coefficient in m^-1 (from previous example)

+T=2*%pi/lambda0*(ne1-ne2)-K;//Phase mismatch in m^-1

+y=sqrt(k^2+(T/2)^2);//Resultant of k and T in m^-1

+

+mprintf("\n For A=100 um:");

+P2max=(k/y)^2;//Maximum power that gets transferred between the modes

+mprintf("\n P2max= %.1e",P2max);

+L=%pi/(2*y);//Distance for maximum power transfer in m

+mprintf("\n L=%.1f um\n",L/1e-6);//Division by 10^(-6) to convert into um

+//The answers vary due to round off error

+

+

+//Case (ii):

+A=148e-6;

+K=2*%pi/A;

+k=0.598e2;//coupling coefficient in m^-1 (from previous example)

+T=2*%pi/lambda0*(ne1-ne2)-K;//Phase mismatch in m^-1

+y=sqrt(k^2+(T/2)^2);//Resultant of k and T in m^-1

+

+mprintf("\n For A=148 um:");

+P2max=(k/y)^2;//Maximum power that gets transferred between the modes

+mprintf("\n P2max= %.1e",P2max);

+L=%pi/(2*y);//Distance for maximum power transfer in m

+mprintf("\n L=%.1f mm",L/1e-3);//Division by 10^(-6) to convert into mm

+

diff --git a/3638/CH21/EX21.3/Ex21_3.jpg b/3638/CH21/EX21.3/Ex21_3.jpg
new file mode 100644
index 000000000..cd5d9dd30
--- /dev/null
+++ b/3638/CH21/EX21.3/Ex21_3.jpg
diff --git a/3638/CH21/EX21.3/Ex21_3.sce b/3638/CH21/EX21.3/Ex21_3.sce
new file mode 100644
index 000000000..5482ad427
--- /dev/null
+++ b/3638/CH21/EX21.3/Ex21_3.sce
@@ -0,0 +1,14 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambdac=0.6e-6;//Wavelength in m

+//Let A be perturbation of length in m

+A=149.3e-6;

+L=2.63e-2;//Length of the periodic waveguide in m

+

+DeltaLambda=0.8*A*lambdac/L;//Bandwidth of the wavelength filter in m

+mprintf("\n DeltaLambda= %.1f nm",DeltaLambda/1e-9);//Division by 10^(-9) to convert into nm

diff --git a/3638/CH21/EX21.4/Ex21_4.jpg b/3638/CH21/EX21.4/Ex21_4.jpg
new file mode 100644
index 000000000..eb37acab3
--- /dev/null
+++ b/3638/CH21/EX21.4/Ex21_4.jpg
diff --git a/3638/CH21/EX21.4/Ex21_4.sce b/3638/CH21/EX21.4/Ex21_4.sce
new file mode 100644
index 000000000..eb99462b7
--- /dev/null
+++ b/3638/CH21/EX21.4/Ex21_4.sce
@@ -0,0 +1,12 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+va=5.96e3;//Velocity of the acoustic wave

+Lb=2e-3;//Beat length in m

+

+f=va/Lb;//Acoustic frequency in Hz for Theta=0 degrees

+mprintf("\n f=%.2f MHz",f/1e6);//Division by 10^6 to convert into MHz

diff --git a/3638/CH21/EX21.5/Ex21_5.jpg b/3638/CH21/EX21.5/Ex21_5.jpg
new file mode 100644
index 000000000..3c25a140c
--- /dev/null
+++ b/3638/CH21/EX21.5/Ex21_5.jpg
diff --git a/3638/CH21/EX21.5/Ex21_5.sce b/3638/CH21/EX21.5/Ex21_5.sce
new file mode 100644
index 000000000..ba0104265
--- /dev/null
+++ b/3638/CH21/EX21.5/Ex21_5.sce
@@ -0,0 +1,14 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.5

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+va=5.96e3;//Velocity of the acoustic wave

+Lb=1.7e-3;//Beat length in m

+Theta=13.5;//Angle between acoustic wave and the light waves

+

+f=va/(Lb*sind(Theta));//Acoustic frequency in Hz

+mprintf("\n f=%.2f MHz",f/1e6);//Division by 10^6 to convert into MHz

+//The answers vary due to round off error

diff --git a/3638/CH21/EX21.6/Ex21_6.jpg b/3638/CH21/EX21.6/Ex21_6.jpg
new file mode 100644
index 000000000..2dd98f612
--- /dev/null
+++ b/3638/CH21/EX21.6/Ex21_6.jpg
diff --git a/3638/CH21/EX21.6/Ex21_6.sce b/3638/CH21/EX21.6/Ex21_6.sce
new file mode 100644
index 000000000..c307626a9
--- /dev/null
+++ b/3638/CH21/EX21.6/Ex21_6.sce
@@ -0,0 +1,24 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.6

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+nf=1.51;//refractive index of film

+ns=1.50;//refractive index of substrate

+nc=1.0;//refractive index of cover

+d=4e-6;//thickness of film in m

+lambda0=0.6e-6;//Wavelength in m

+ne1=1.50862;//Corresponding effective refractive index for core

+ne2=1.5046;//Corresponding effective refractive index for cladding

+//Let A be the perturbation of length in m

+A=6e-6;

+

+//Rearranging the terms of the equation 'ne1-lambda0/A=ns*cos(Thetas0)', we get:

+Thetas0=acosd((ne1-lambda0/A)/ns);

+mprintf("\n Thetas0 = %.1f degrees",Thetas0);

+

+//Rearranging the terms of the equation 'ne2-lambda0/A=ns*cos(Thetas1)', we get:

+Thetas1=acosd((ne2-lambda0/A)/ns);

+mprintf("\n Thetas1 = %.1f degrees",Thetas1);

diff --git a/3638/CH21/EX21.7/Ex21_7.jpg b/3638/CH21/EX21.7/Ex21_7.jpg
new file mode 100644
index 000000000..1359f7cb9
--- /dev/null
+++ b/3638/CH21/EX21.7/Ex21_7.jpg
diff --git a/3638/CH21/EX21.7/Ex21_7.sce b/3638/CH21/EX21.7/Ex21_7.sce
new file mode 100644
index 000000000..11306e0c5
--- /dev/null
+++ b/3638/CH21/EX21.7/Ex21_7.sce
@@ -0,0 +1,24 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.7

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+nf=1.51;//refractive index of film

+ns=1.50;//refractive index of substrate

+nc=1.0;//refractive index of cover

+d=4e-6;//thickness of film in m

+lambda0=0.6e-6;//Wavelength in m

+ne1=1.50862;//Corresponding effective refractive index for core

+ne2=1.5046;//Corresponding effective refractive index for cladding

+//Let A be the perturbation of length in m

+A=0.2e-6;

+

+//Rearranging the terms of the equation 'ne1-lambda0/A=ns*cos(Thetas0)', we get:

+Thetas0=acosd((ne1-lambda0/A)/ns);

+mprintf("\n Thetas0 = %.1f degrees",Thetas0);

+

+//Rearranging the terms of the equation 'ne2-lambda0/A=ns*cos(Thetas1)', we get:

+Thetas1=acosd((ne2-lambda0/A)/ns);

+mprintf("\n Thetas1 = %.1f degrees",Thetas1);

diff --git a/3638/CH21/EX21.8/Ex21_8.jpg b/3638/CH21/EX21.8/Ex21_8.jpg
new file mode 100644
index 000000000..6ff3e8a65
--- /dev/null
+++ b/3638/CH21/EX21.8/Ex21_8.jpg
diff --git a/3638/CH21/EX21.8/Ex21_8.sce b/3638/CH21/EX21.8/Ex21_8.sce
new file mode 100644
index 000000000..2ee948662
--- /dev/null
+++ b/3638/CH21/EX21.8/Ex21_8.sce
@@ -0,0 +1,26 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.8

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//Since the peak reflectivity of fiber is 0.98,

+R=0.98;//Reflection coefficient of fiber

+L=1e-3;//Length of interaction in m

+lambda0=1092e-9;//Central wavelength in m

+neff=1.46;//Corresponding value of effective index in LP01 mode

+

+//Now, (tanh(k*L))^2=R

+//Rearranging terms, we get:

+k=atanh(sqrt(R))/L;//Corresponding coupling coefficient in m^(-1)

+mprintf("\n k=%.3f mm^(-1)",k/1e3);//Dividing by 10^3 to convert into mm^(-1)

+//The answers vary due to round off error

+

+//Let A be the perturbation of length in m

+A=lambda0/(2*neff);

+mprintf("\n A=%.2f um",A/1e-6);//Division by 10^(-6) to convert into um

+

+DeltaLambda=lambda0*A/L;//Corresponding bandwidth in m

+mprintf("\n DeltaLambda=%.2f nm",DeltaLambda/1e-9);//Division by 10^(-9) to convert into nm

+//The answers vary due to round off error

diff --git a/3638/CH21/EX21.9/Ex21_9.jpg b/3638/CH21/EX21.9/Ex21_9.jpg
new file mode 100644
index 000000000..8b8e05dfd
--- /dev/null
+++ b/3638/CH21/EX21.9/Ex21_9.jpg
diff --git a/3638/CH21/EX21.9/Ex21_9.sce b/3638/CH21/EX21.9/Ex21_9.sce
new file mode 100644
index 000000000..b4ffd2f6e
--- /dev/null
+++ b/3638/CH21/EX21.9/Ex21_9.sce
@@ -0,0 +1,26 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 21.9

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+//Since the peak reflectivity of fiber is 0.85,

+R=0.85;//Reflection coefficient of fiber

+L=1e-2;//Length of interaction in m

+lambda0=1.55e-6;//Central wavelength in m

+neff=1.46;//Corresponding value of effective index in LP01 mode

+

+//Now, (tanh(k*L))^2=R

+//Rearranging terms, we get:

+k=atanh(sqrt(R))/L;//Corresponding coupling coefficient in m^(-1)

+mprintf("\n k=%.3f m^(-1)",k);//The answer provided in the textbook is wrong

+

+//Let A be the perturbation of length in m

+A=lambda0/(2*neff);

+mprintf("\n A=%.2f nm",A/1e-9);//Division by 10^(-9) to convert into nm

+//The answers vary due to round off error

+

+DeltaLambda=lambda0^2/(%pi*neff*L)*sqrt((k*L)^2+(%pi)^2);//Corresponding bandwidth in m

+mprintf("\n DeltaLambda=%.2f nm",DeltaLambda/1e-9);//Division by 10^(-9) to convert into nm

+//The answer provided in the textbook is wrong

diff --git a/3638/CH7/EX7.1/Ex7_1.jpg b/3638/CH7/EX7.1/Ex7_1.jpg
new file mode 100644
index 000000000..9a097defd
--- /dev/null
+++ b/3638/CH7/EX7.1/Ex7_1.jpg
diff --git a/3638/CH7/EX7.1/Ex7_1.sce b/3638/CH7/EX7.1/Ex7_1.sce
new file mode 100644
index 000000000..afac2c184
--- /dev/null
+++ b/3638/CH7/EX7.1/Ex7_1.sce
@@ -0,0 +1,56 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 7.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given 

+n1=1.503;//refractive index of film

+n2=1.500;//refractive index of cover

+d=4e-6;//thickness of film in m

+

+

+//Case(1)

+lambda0=1e-6;//wavelength  in m

+k0=2*(%pi)/lambda0;//free space wave number in rad/m

+funcprot(0);//To avoid warning message when function is redefined

+mprintf("\n For 1st value of lambda:");

+V=k0*d*sqrt((n1^2)-(n2^2));//dimensionless waveguide parameter

+mprintf("\n V=%f",V);//The answers vary due to round off error

+

+//To find Xi for symmetric TE mode

+deff('t=f(Xi)','t=V/2*cos(Xi)-Xi');//Rearranging the terms of eqn for symmetric TE modes i.e. 'ξtanξ=((V/2)^2-ξ^2)', we get 'ξ=V/2*cos(ξ)'

+Xi0=0;//Starting value of Xi

+Xi=fsolve(Xi0,f);//Root of eqn 't=0'

+mprintf("\n For symmetric mode ξ=%f",Xi);//The answers vary due to round off error

+b=1-(Xi^2)/(V^2/4);//dimensionless propagation constant

+mprintf("\n b=%f",b);

+B=sqrt(b*((n1^2)-(n2^2))+(n2^2));

+mprintf("\nBeta/k0=%f",B);//The answers vary due to round off error

+

+

+//Case(2)

+lambda0=0.5e-6;//wavelength  in m

+k0=2*(%pi)/lambda0;//phase constant in rad/m

+mprintf("\n\n For 2nd value of lambda:");

+V=k0*d*sqrt((n1^2)-(n2^2))//dimensionless waveguide parameter

+mprintf("\n V=%f ",V);//The answers vary due to round off error

+

+//To find Xi for symmetric TE mode

+deff('t=f(Xi)','t=V/2*cos(Xi)-Xi');//Rearranging the terms of eqn for symmetric TE modes i.e. 'ξtanξ=((V/2)^2-ξ^2)^(1/2)', we get 'ξ=V/2*cos(ξ)'

+Xi0=0;//Starting value of Xi

+Xi=fsolve(Xi0,f);//Root of eqn 't=0'

+mprintf("\n For symmetric mode ξ=%f",Xi);//The answers vary due to round off error

+b=1-(Xi^2)/(V^2/4);//dimensionless propagation constant

+mprintf("\n b=%f",b);

+B=sqrt(b*((n1^2)-(n2^2))+(n2^2));

+mprintf("\nBeta/k0=%f",B);

+//To find Xi for antisymmetric TE mode

+deff('t=f(Xi)','t=V/2*sin(Xi)-Xi');//Rearranging the terms of eqn for antisymmetric TE modes i.e. '-ξcotξ=((V/2)^2-ξ^2)^(1/2)', we get 'ξ=V/2*sin(ξ)'

+Xi0=1;//Starting value of Xi

+Xi=fsolve(Xi0,f);//Root of eqn 't=0'

+mprintf("\n For antisymmetric mode ξ=%f",Xi);//The answers vary due to round off error

+b=1-(Xi^2)/(V^2/4);//dimensionless propagation constant

+mprintf("\n b=%f",b);

+B=sqrt(b*((n1^2)-(n2^2))+(n2^2));

+mprintf("\nBeta/k0=%f",B);

diff --git a/3638/CH7/EX7.2/Ex7_2.jpg b/3638/CH7/EX7.2/Ex7_2.jpg
new file mode 100644
index 000000000..9307cb611
--- /dev/null
+++ b/3638/CH7/EX7.2/Ex7_2.jpg
diff --git a/3638/CH7/EX7.2/Ex7_2.sce b/3638/CH7/EX7.2/Ex7_2.sce
new file mode 100644
index 000000000..87a7c00af
--- /dev/null
+++ b/3638/CH7/EX7.2/Ex7_2.sce
@@ -0,0 +1,35 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 7.2

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given 

+n1=1.5;//refractive index of film

+n2=1.0;//refractive index of cover

+d=.555e-6;//thickness of film in m

+

+

+//Case(1)

+lambda0=1.3e-6;//wavelength in m

+k0=2*(%pi)/lambda0;//free space wave number in rad/m

+V=k0*d*sqrt((n1^2)-(n2^2));//dimensionless waveguide parameter

+mprintf("V=%f \n",V);//The answers vary due to round off error

+

+//To find Xi for symmetric TE mode

+deff('t=f(Xi)','t=V/2*cos(Xi)-Xi');//Rearranging the terms of eqn for symmetric TE modes i.e. 'ξtanξ=((V/2)^2-ξ^2)', we get 'ξ=V/2*cos(ξ)'

+Xi0=0;//Starting value of Xi

+Xi=fsolve(Xi0,f);//Root of eqn 't=0'

+b=1-(Xi^2)/(V^2/4);//dimensionless propagation constant

+mprintf("\n b=%f",b);//The answers vary due to round off error

+B=sqrt(b*((n1^2)-(n2^2))+(n2^2));

+mprintf("\nBeta/k0=%f",B);//The answers vary due to round off error

+

+//To find Xi for symmetric TM mode

+deff('t=f(Xi)','t=(1-(n1/n2)^2)*(Xi^2)+(V^2)/4-(Xi*sec(Xi))^2');//Rearranging the terms of eqn for symmetric TE modes i.e. 'ξtanξ=((V/2)^2-ξ^2)', we get 'ξ=V/2*cos(ξ)'

+Xi0=0;//Starting value of Xi

+Xi=fsolve(Xi0,f);//Root of eqn 't=0'

+b=1-(Xi^2)/(V^2/4);//dimensionless propagation constant

+mprintf("\n b=%f",b);//The answer provided in the textbook is wrong

+B=sqrt(b*((n1^2)-(n2^2))+(n2^2));

+mprintf("\nBeta/k0=%f",B);//The answer provided in the textbook is wrong

diff --git a/3638/CH8/EX8.1/Ex8_1.jpg b/3638/CH8/EX8.1/Ex8_1.jpg
new file mode 100644
index 000000000..e111b4f38
--- /dev/null
+++ b/3638/CH8/EX8.1/Ex8_1.jpg
diff --git a/3638/CH8/EX8.1/Ex8_1.sce b/3638/CH8/EX8.1/Ex8_1.sce
new file mode 100644
index 000000000..571d79a35
--- /dev/null
+++ b/3638/CH8/EX8.1/Ex8_1.sce
@@ -0,0 +1,31 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.1

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given Case(1) 

+n2=1.45;//refractive index of cladding

+a=3e-6;//radius of core in m

+delta=0.0064//fractional change in refractive index

+lambda0=1.546e-6;//wavelength  in m

+n1=n2/(1-delta);//refractive index of core

+V=2*(%pi)*a*sqrt((n1^2)-(n2^2))/lambda0;//corresponding dimensionless V number

+mprintf("\n For fiber 1:");

+mprintf("\n V=%.1f at lambda0=%.3f um ",V,lambda0/1e-6);//Division by 10^(-6) to convert into um

+b=0.41616;//value of dimensionless propagation constant corresponding to V=2 as per given table

+B=sqrt((n2^2)+b*((n1^2)-(n2^2)));//corresponding value of Beta/k0

+mprintf("\n Beta/k0=%f",B);//The answers vary due to round off error

+

+//given Case(2)

+n2=1.45;//refractive index of cladding

+a=2e-6;//radius of core in m

+delta=0.010//fractional change in refractive index

+lambda0=1.288e-6;//wavelength  in m

+n1=n2/(1-delta);//refractive index of core

+V=2*(%pi)*a*sqrt((n1^2)-(n2^2))/lambda0;//corresponding dimensionless V number

+mprintf("\n For fiber 2:");

+mprintf("\n V=%.1f at lambda0=%.3f um ",V,lambda0/1e-6);//Division by 10^(-6) to convert into um

+b=0.41616;//value of dimensionless propagation constant corresponding to V=2 as per given table

+B=sqrt((n2^2)+b*((n1^2)-(n2^2)));//corresponding value of Beta/k0

+mprintf("\n Beta/k0=%f",B);//The answers vary due to round off error

diff --git a/3638/CH8/EX8.3/Ex8_3.jpg b/3638/CH8/EX8.3/Ex8_3.jpg
new file mode 100644
index 000000000..f2c1c6592
--- /dev/null
+++ b/3638/CH8/EX8.3/Ex8_3.jpg
diff --git a/3638/CH8/EX8.3/Ex8_3.sce b/3638/CH8/EX8.3/Ex8_3.sce
new file mode 100644
index 000000000..bff1d201c
--- /dev/null
+++ b/3638/CH8/EX8.3/Ex8_3.sce
@@ -0,0 +1,12 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.3

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1300e-9;//operating wavelength of single mode fiber in m

+omega=5e-6;//spot size of fiber in m

+alphat=0.1;//maximum value of loss in dB

+u=sqrt(alphat*(omega^2)/4.34);//corresponding maximum value of transverse offset in m 

+mprintf("Maximum value of u=%.2f um",u/1e-6);//division by 1e-6 to convert in um

diff --git a/3638/CH8/EX8.4/Ex8_4.jpg b/3638/CH8/EX8.4/Ex8_4.jpg
new file mode 100644
index 000000000..3134a8be5
--- /dev/null
+++ b/3638/CH8/EX8.4/Ex8_4.jpg
diff --git a/3638/CH8/EX8.4/Ex8_4.sce b/3638/CH8/EX8.4/Ex8_4.sce
new file mode 100644
index 000000000..84a33eaca
--- /dev/null
+++ b/3638/CH8/EX8.4/Ex8_4.sce
@@ -0,0 +1,14 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.4

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1300e-9;//operating wavelength of single mode fiber in m

+omega=5e-6;//spot size of fiber in m

+n1=1.45;//refractive index of core

+n2=1.45;//refractive index of cladding

+alphat=0.1;//maximum value of splice loss due to angular misalignment in dB

+theta=sqrt(alphat*(lambda0^2)/(4.34*((%pi)*n1*omega)^2));//corresponding maximum value of angular misalignment in radians

+mprintf("Maximum value of theta=%.1f degrees",theta*180/(%pi));//multiplying by 180/pi to convert in degrees

diff --git a/3638/CH8/EX8.5/Ex8_5.jpg b/3638/CH8/EX8.5/Ex8_5.jpg
new file mode 100644
index 000000000..fa6c60656
--- /dev/null
+++ b/3638/CH8/EX8.5/Ex8_5.jpg
diff --git a/3638/CH8/EX8.5/Ex8_5.sce b/3638/CH8/EX8.5/Ex8_5.sce
new file mode 100644
index 000000000..2b0aad6d6
--- /dev/null
+++ b/3638/CH8/EX8.5/Ex8_5.sce
@@ -0,0 +1,16 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.5

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1300e-9;//operating wavelength of single mode fiber in m

+omega=5e-6;//spot size of fiber in m

+n1=1.45;//refractive index of core

+n2=1.45;//refractive index of cladding

+D=20e-6;//longitudinal misalignment in m

+Dbar=D*lambda0/(2*(%pi)*n1*(omega^2));//dimensionless normalized separation 

+mprintf("Dbar=%f",Dbar);//The answers vary due to round off error

+alphat=10*log10(1+(Dbar^2));//corresponding value of splice loss due to longitudinal misalignment in dB

+mprintf("\n Corresponding value of splice loss=%.2f dB",alphat);

diff --git a/3638/CH8/EX8.6/Ex8_6.jpg b/3638/CH8/EX8.6/Ex8_6.jpg
new file mode 100644
index 000000000..4d3bb9c07
--- /dev/null
+++ b/3638/CH8/EX8.6/Ex8_6.jpg
diff --git a/3638/CH8/EX8.6/Ex8_6.sce b/3638/CH8/EX8.6/Ex8_6.sce
new file mode 100644
index 000000000..460a95753
--- /dev/null
+++ b/3638/CH8/EX8.6/Ex8_6.sce
@@ -0,0 +1,12 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.6

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1300e-9;//operating wavelength of single mode fiber in m

+MFD=10e-6;//mode field diameter of fiber in m

+omega=MFD/2;//corresponding spot size of fiber in m

+thetae=asind(lambda0/(%pi*omega));//corresponding value of angle in degrees where amplitude falls to 1/e of maximum value

+mprintf("Corresponding value of angle=%.2f degrees",thetae);

diff --git a/3638/CH8/EX8.7/Ex8_7.jpg b/3638/CH8/EX8.7/Ex8_7.jpg
new file mode 100644
index 000000000..ba2b9dca9
--- /dev/null
+++ b/3638/CH8/EX8.7/Ex8_7.jpg
diff --git a/3638/CH8/EX8.7/Ex8_7.sce b/3638/CH8/EX8.7/Ex8_7.sce
new file mode 100644
index 000000000..409e8cf79
--- /dev/null
+++ b/3638/CH8/EX8.7/Ex8_7.sce
@@ -0,0 +1,12 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.7

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=633e-9;//operating wavelength of single mode fiber in m

+MFD=5e-6;//mode field diameter of fiber in m

+omega=MFD/2;//corresponding spot size of fiber in m

+thetae=asind(lambda0/(%pi*omega));//corresponding value of angle in degrees where amplitude falls to 1/e of maximum value

+mprintf("Corresponding value of angle=%.2f degrees",thetae);

diff --git a/3638/CH8/EX8.8/Ex8_8.jpg b/3638/CH8/EX8.8/Ex8_8.jpg
new file mode 100644
index 000000000..37e77dd21
--- /dev/null
+++ b/3638/CH8/EX8.8/Ex8_8.jpg
diff --git a/3638/CH8/EX8.8/Ex8_8.sce b/3638/CH8/EX8.8/Ex8_8.sce
new file mode 100644
index 000000000..0bdab9bd1
--- /dev/null
+++ b/3638/CH8/EX8.8/Ex8_8.sce
@@ -0,0 +1,14 @@
+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.8

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1.3e-6;//operating wavelength of single mode fiber in m

+thetah=2.74;//angle corresponding to 3 dB point in degrees

+k0=2*%pi/lambda0;//free space wave number in rad/m

+omega=sqrt(2*log(2))/(k0*sind(2.74));//corresponding spot size of fiber in m

+d=2*omega;//corresponding value of Gaussian mode field diameter in m

+mprintf("Corresponding mode field diameter=%f um",d/1e-6)//division by 1e-6 to convert in um 

+//The answer provided in the textbook is wrong

diff --git a/3638/CH8/EX8.9/Ex8_9.jpg b/3638/CH8/EX8.9/Ex8_9.jpg
new file mode 100644
index 000000000..50ad46336
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+//Introduction to Fiber Optics by A. Ghatak and K. Thyagarajan, Cambridge, New Delhi, 1999

+//Example 8.9

+//OS=Windows XP sp3

+//Scilab version 5.5.2

+clc;

+clear;

+//given

+lambda0=1.3e-6;//operating wavelength of single mode fiber in m

+thetah=2.357;//angle corresponding to 3 dB point in degrees

+thetax=12.73;//angle in degrees at which intensity first becomes zero

+sigmax=sind(thetax)/sind(thetah);//ratio of sine of angles

+V=8.039-2.347*sigmax+0.3329*sigmax^2-0.0218*sigmax^3+0.00054*sigmax^4;//corresponding dimensionless V number

+alphah=-0.7858+0.994*V-0.1155*V^2;

+k0=2*%pi/lambda0;//free space wave number in rad/m

+a=alphah/(k0*sind(thetah));//radius of core in m

+NA=V*lambda0/(2*%pi*a);//corresponding value of numerical aperture

+mprintf("The ESI parameters of given fiber are:");

+mprintf("\n Radius of core=%f um",a/1e-6);//division by 1e-6 to convert in um

+//The answers vary due to round off error

+mprintf("\n Numerical aperture=%.2f",NA);