bmarechal / sicav_sim

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Commit 07295cdf4404fcda6800f4183bad53f4e4179a58

Authored by bmarechal
1 parent 0cbce28efb
Exists in master

add PDH_error_signal numeric simulation

Showing 2 changed files with 84 additions and 0 deletions Side-by-side Diff

PDH_error_signal/PDH_error_signal.m
Diff comments   View file @ 07295cd
  1 +clear
  2 +clc
  3 +close all
  4 +
  5 +L = 10e-2
  6 +c = 299792458
  7 +R = 0.99991
  8 +
  9 +fsr = c/(2*L)
  10 +
  11 +fc = fsr*128760;
  12 +df=20e6;
  13 +
  14 +f = 2*pi*linspace(fc-df, fc+df, 10000);
  15 +
  16 +fpt = ((1.-R).*exp(-2.*L.*i.*f./c))./(1.-R.*exp(-2.*L.*i.*f./c));
  17 +fpr = sqrt(R).*(1.-exp(-2.*L.*i.*f./c))./(1.-R.*exp(-2.*L.*i.*f./c));
  18 +
  19 +figure
  20 +plot(f,abs(fpr))
  21 +
  22 +
  23 +fm = 23e6;
  24 +
  25 +fm1 = sqrt(R).*(1.-exp(-2.*L.*i.*(f.+fm)./c))./(1.-R.*exp(-2.*L.*i.*(f.+fm)./c));
  26 +fm2 = sqrt(R).*(1.-exp(-2.*L.*i.*(f.-fm)./c))./(1.-R.*exp(-2.*L.*i.*(f.-fm)./c));
  27 +
  28 +ff=fpr.*conj(fm1)-conj(fpr).*fm2;
  29 +iff = imag(ff);
  30 +
  31 +figure
  32 +plot(f,iff)
PDH_error_signal/PDH_error_signal.py
Diff comments   View file @ 07295cd
  1 +#!/usr/bin/env python
  2 +
  3 +import numpy
  4 +import matplotlib.pyplot as plt
  5 +
  6 +L = 14e-2
  7 +c = 299792458
  8 +R = 0.99991
  9 +
  10 +fsr = c/(2*L)
  11 +print("fsr = %f GHz"%(fsr/1e9))
  12 +
  13 +finesse = numpy.pi*R**0.25/(1-R**0.5)
  14 +print("finesse = %i"%finesse)
  15 +
  16 +print("finesse/fsr = %f s"%(finesse/fsr))
  17 +
  18 +fc = fsr*130000
  19 +df = 20e6
  20 +#print(fc)
  21 +
  22 +f = 2*numpy.pi*numpy.linspace(fc-df, fc+df, 100000) # frequency array
  23 +i = complex(0,1)
  24 +
  25 +fpt = ((1.-R)*numpy.exp(-2.*L*i*f/c))/(1.-R*numpy.exp(-2.*L*i*f/c))
  26 +fpr = R**0.5*(1.-numpy.exp(-2.*L*i*f/c))/(1.-R*numpy.exp(-2.*L*i*f/c))
  27 +
  28 +plt.subplot(2, 1, 1)
  29 +plt.plot(f, abs(fpr))
  30 +plt.title('FP cavity')
  31 +plt.ylabel('Reflective intensity')
  32 +plt.grid()
  33 +
  34 +
  35 +fm = 23e6
  36 +ram = 0
  37 +
  38 +fm1 = R**0.5*(1.-numpy.exp(-2.*L*i*(f+fm)/c))/(1.-R*numpy.exp(-2.*L*i*(f+fm)/c)) + ram*i
  39 +fm2 = R**0.5*(1.-numpy.exp(-2.*L*i*(f-fm)/c))/(1.-R*numpy.exp(-2.*L*i*(f-fm)/c)) + ram*i
  40 +
  41 +ff = fpr*fm1.conjugate()-fpr.conjugate()*fm2
  42 +iff = ff.imag
  43 +
  44 +
  45 +plt.subplot(2, 1, 2)
  46 +plt.plot(f, iff)
  47 +plt.xlabel('Frequency')
  48 +plt.ylabel('PDH')
  49 +plt.grid()
  50 +
  51 +
  52 +plt.show()