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{
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{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter10 - Optical Amplifiers"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 10.1 : Page 254"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
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},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"refrative index is : 3.75\n",
"spectral bandwidth = 2.09 GHz\n"
]
}
],
"source": [
"from math import pi, asin, sqrt\n",
"from __future__ import division\n",
"#refractive index and bandwidth\n",
"#given data :\n",
"lamda=1.55*10**-6## in m\n",
"del_lamda=1*10**-9## in m\n",
"L=320*10**-6## in m\n",
"n=(lamda)**2/(2*del_lamda*L)#\n",
"Gs=10**(5/10)## 5 dB is equivalent to 3.16\n",
"R1=30/100#\n",
"R2=R1#\n",
"c=3*10**8## in m/s\n",
"del_v=(c/(pi*n*L))*asin((1-(Gs*sqrt(R1*R2)))/(sqrt(4*Gs*sqrt(R1*R2))))#\n",
"print \"refrative index is : %0.2f\"%n\n",
"print \"spectral bandwidth = %0.2f GHz\"%(del_v*10**-9)\n",
"#bandwidth is calculated wrong in the textbook"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 10.2 : Page 260"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"small signal gain of EDFA = 32.91 dB\n",
"maximum possible achievable gain = 84.71 dB\n"
]
}
],
"source": [
"from math import log10, exp\n",
"#small-signal gain of EDFA and maximum pssible achievable gain\n",
"ts=0.80##\n",
"sa=4.6444*10**-25##in m**2\n",
"n12=6*10**24##m**-3\n",
"se=4.644*10**-25##m**2\n",
"n21=0.70##\n",
"l=7##in meter\n",
"x=((sa*n12*l*(((se/sa)+1)*n21-1)))##\n",
"G=ts*exp(x)##\n",
"Gdb=10*log10(G)##\n",
"Gmax=exp(se*n12*l)##\n",
"Gmaxdb=10*log10(Gmax)##\n",
"print \"small signal gain of EDFA = %0.2f dB\"%Gdb\n",
"print \"maximum possible achievable gain = %0.2f dB\"%Gmaxdb"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 10.3 : Page 264"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"part (a)\n",
"output signal power for forward pumping = 4.60 micro Watt\n",
"part (b)\n",
"overall gain = 6.63 dB\n"
]
}
],
"source": [
"#output signal power and overall gain\n",
"print \"part (a)\"\n",
"psin=1*10**-6##in watts\n",
"ppin=1##in watts\n",
"gr=5*10**-14##mW**-1\n",
"ap1=60*10**-12##m**2\n",
"l=2000##meter\n",
"asdb=0.15##dB/km\n",
"As=3.39*10**-5##m**-1\n",
"apdb=0.20##db/km\n",
"ap=4.50*10**-5##m**-1\n",
"z=(1-exp(-ap*l))/ap##\n",
"y=(gr/ap1)##\n",
"y1=z*y##\n",
"y2=y1-(As*l)##\n",
"psl=psin*exp(y2)##\n",
"print \"output signal power for forward pumping = %0.2f micro Watt\"%(psl*10**6)\n",
"print \"part (b)\"\n",
"y1=z*y##\n",
"y2=y1-(As*l)##\n",
"psl=psin*exp(y2)##\n",
"gfra=psl/(psin)##\n",
"Gdb=10*log10(gfra)##\n",
"print \"overall gain = %0.2f dB\"%Gdb"
]
}
],
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