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bad-samaritan / Polmux

A multichannel PolMUX QPSK transmission simulation with Optilux
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Some questions about the lasersouce.m #2

Open JOKERSUP opened 3 years ago

JOKERSUP commented 3 years ago

Hello Paolo Serena, I have just downloaded your codes, and they are very usefull and helpfull for my studying. Here I have a little doubt about the lasersource.m.. Codesfrom row 182 to row 195 is the simulation of laser phase noise, I can understand the frist part: freq_noise = (ones(nfft,1) sqrt(2pilinewidth./GSTATE.NT)) . randn( nfft, nch); freq_noise(1) = 0; phase_noise = cumsum(freq_noise,1);

but I dont know why the next part is in need: % Brownian bridge for nnoise=1:length(phase_noise) phase_noise(nnoise)=phase_noise(nnoise)-(nnoise-1)/... (length(phase_noise)-1)*phase_noise(end); end

I dont understand why to force the initial phase and final phase to zero. Could u please provide some papers or references about the part?

JOKERSUP commented 3 years ago

Here are some papers, according to which, I believe the "Brownian bridge" part is unnecessary.

Characterization of semiconductor-laser phase noise and estimation of bit-error rate performance with low-speed offline digital coherent receivers. (2012 Optical Express)

Phase Noise Characterization of a Mode-Locked QuantumDot Coherent Optical Frequency Comb Source Laser. (2018 OFC Conference)