from __future__ import division x=0.07 Eg=1.424+1.266*x+0.266*x**2 lamda=1.24/Eg #computing wavelength print "Wavlength is %.3f micrometer." %lamda
Wavlength is 0.819 micrometer.
n=1.7 #refractive index L=5*10**-2 #distance between mirror c=3*10**8 #speed of light lamda=0.45*10**-6 #wavelength k=2*n*L/lamda #computing number of modes delf=c/(2*n*L) #computing mode separation delf=delf*10**-9 print "Number of modes are %.2e.\nFrequency separation is %.2f GHz."%(k,delf)
Number of modes are 3.78e+05. Frequency separation is 1.76 GHz.
from __future__ import division tr=50 #radiative recombination lifetime tnr=85 #non-radiative recombination lifetime h=6.624*10**-34 #plank's constant c=3*10**8 #speed of light q=1.6*10**-19 #charge of electron i=35*10**-3 #current lamda=0.85*10**-6 #wavelength t=tr*tnr/(tr+tnr) #computing total recombination time eta=t/tr #computing internal quantum efficiency Pint=eta*h*c*i/(q*lamda) #computing internally generated power Pint=Pint*10**3 print "Total recombinaiton time is %.2f ns.\nInternal quantum efficiency is %.3f.\nInternally generated power is %.2f mW." %(t,eta,Pint) #answer in the book for Internal quantum efficiency & Internally generated power is wrong.
Total recombinaiton time is 31.48 ns. Internal quantum efficiency is 0.630. Internally generated power is 32.20 mW.
from numpy import sqrt, pi f1=10*10**6 #frequency f2=100*10**6 t=4*10**-9 Pdc=280*10**-6 #optincal output power w1=2*pi*f1 #computing omega Pout1=Pdc*10**6/(sqrt(1+(w1*t)**2)) #computing output power w2=2*pi*f2 #computing omega Pout2=Pdc*10**6/(sqrt(1+(w2*t)**2)) #computing output power print """Ouput power at 10 MHz is %.2f microwatt. Ouput power at 100 MHz is %.2f microwatt. Conclusion when device is drive at higher frequency the optical power reduces.""" %(Pout1,Pout2) BWopt = sqrt(3)/(2*pi*t) BWelec = BWopt/sqrt(2) BWopt=BWopt*10**-6 BWelec=BWelec*10**-6 print "3 dB optical power is %.2f MHz.\n3 dB electrical power is %.2f MHz." %(BWopt,BWelec) #calculation error. In the book square term in the denominater is not taken. #answers in the book are wrong.
Ouput power at 10 MHz is 271.55 microwatt. Ouput power at 100 MHz is 103.52 microwatt. Conclusion when device is drive at higher frequency the optical power reduces. 3 dB optical power is 68.92 MHz. 3 dB electrical power is 48.73 MHz.
n1=3.5 #refractive index n=1 #refractive index of air F=0.69 #transmission factor eta = 100*(n1*(n1+1)**2)**-1 #computing eta print "eta external is %.1f percent i.e. small fraction of intrnally generated opticalpower is emitted from the device." %eta r= 100*F*n**2/(4*n1**2) #computing ratio of Popt/Pint print "Popt/Pint is %.1f percent" %r #printing mistake at final answer.
eta external is 1.4 percent i.e. small fraction of intrnally generated opticalpower is emitted from the device. Popt/Pint is 1.4 percent
from numpy import log, exp beta0=1.85*10**7 T=293 #temperature k=1.38*10**-23 #Boltzman constant Ea=0.9*1.6*10**-19 theta=0.65 #thershold betar=beta0*exp(-Ea/(k*T)) t=-log(theta)/betar print "Degradation rate is %.1e per hour.\nOperating lifetime is %.1e hour." %(betar,t) #answer in the book for Degradation rate & Operating lifetime is wrong.
Degradation rate is 6.3e-09 per hour. Operating lifetime is 6.8e+07 hour.