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This commit is contained in:
Silas Oettinghaus
2023-05-15 10:32:24 +02:00
parent c2804fe2a0
commit 55db794162
4 changed files with 190 additions and 16 deletions
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2
Classes/Amplifier.m
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@@ -97,7 +97,7 @@ classdef Amplifier
if obj.amp_mode == "output_power"
seemsright = pow_out_dbm == obj.amplification_db;
else obj.amp_mode == "gain"
elseif obj.amp_mode == "gain"
seemsright = pow_out_dbm == pow_in_dbm+ obj.amplification_db;
end

125
Classes/Fiber.m
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@@ -3,6 +3,7 @@ classdef Fiber
% Detailed explanation goes here
properties
fsimu
fiber_length
alpha
D
@@ -10,6 +11,11 @@ classdef Fiber
lambda0
gamma
dphimax
b2
b3
alpha_lin
linstep
end
methods
@@ -17,6 +23,7 @@ classdef Fiber
%FIBER Construct an instance of this class
% Detailed explanation goes here
arguments
options.fsimu
options.fiber_length = 0
options.alpha = 0.2
options.D = 17
@@ -26,13 +33,21 @@ classdef Fiber
options.dphimax = 5e-3
end
obj.fiber_length = options.fiber_length*1000; %km
obj.alpha = options.alpha;
obj.D =options.D*1e-6;
obj.Dslope =options.Dslope;
obj.lambda0 =options.lambda0;
obj.gamma =options.gamma;
obj.dphimax =options.dphimax;
obj.fsimu = options.fsimu;
obj.fiber_length = options.fiber_length*1000; %km
obj.alpha = options.alpha;
obj.D = options.D*1e-6;
obj.Dslope = options.Dslope*1e3;
obj.lambda0 = options.lambda0*1e-9;
obj.gamma = options.gamma;
obj.dphimax = options.dphimax;
obj.b2 = -obj.D*obj.lambda0^2/(2*pi*Constant.LightSpeed);
obj.b3 = ((obj.lambda0.^2/(2*pi*Constant.LightSpeed)).^2*obj.Dslope);
obj.alpha_lin = obj.alpha/10*log(10)/1000;
end
@@ -40,12 +55,108 @@ classdef Fiber
%METHOD1 Summary of this method goes here
% Detailed explanation goes here
N = length(opt_in);
faxis = linspace(-obj.fsimu/2,obj.fsimu/2,N+1);
faxis = ifftshift(faxis(:,1:end-1));
faxis = faxis';
obj.linstep = -obj.alpha_lin/2 - 2*1j*pi^2*obj.b2*faxis.^2 - 4/3*1j*pi^3*obj.b3*faxis.^3;
opt_out = obj.NLSE(opt_in);
%attenuate nase
end
function [yout] = NLSE(obj, xin)
maxPow = obj.gamma.*max(abs(xin).^2);
Leff = obj.dphimax / maxPow ;
dz = Leff;
z_prop = 0;
yout = fft(xin);
yout = ((yout).*exp(obj.linstep*dz/2));
while true
yout = ifft(yout);
Leff = dz;
power = abs(yout).^2;
Hnl = exp( -1j*obj.gamma*power*Leff);
yout = yout .* Hnl;
z_prop = z_prop + dz;
maxPow = obj.gamma*max(abs(yout).^2);
Leff = obj.dphimax/maxPow;
dz_new = Leff;
if z_prop + dz_new > obj.fiber_length
dz_new = obj.fiber_length - z_prop;
break
end
yout = fft(yout);
yout = ((yout).*exp(obj.linstep*(dz/2+dz_new/2)));
dz = dz_new;
end
yout = fft(yout);
yout = ((yout).*exp(obj.linstep*(dz/2+dz_new/2)));
yout = ifft(yout);
Leff = dz;
power = abs(yout).^2;
Hnl = exp( -1j*obj.gamma*power*Leff);
yout = yout .* Hnl;
yout = fft(yout);
yout = ((yout).*exp(obj.linstep*(dz/2)));
yout = ifft(yout);
end
function yout = process_nonlinstep(xin,stepsize)
end
function yout = process_linstep(xin,stepsize)
end
end
end

63
Classes/Photodiode.m Normal file
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@@ -0,0 +1,63 @@
classdef Photodiode
%PGOTODIODE Summary of this class goes here
% Detailed explanation goes here
properties
fsimu
responsivity
dark_current
temperature
end
methods
function obj = Photodiode(options)
%PHOTODIODE Construct an instance of this class
% Detailed explanation goes here
arguments
options.fsimu
options.responsivity = 1;
options.dark_current = 0;
options.temperature = 20;
end
obj.fsimu = options.fsimu;
obj.responsivity = options.responsivity;
obj.dark_current = options.dark_current;
obj.temperature = options.temperature;
end
function yout = process(obj,xin)
%METHOD1 Summary of this method goes here
% Detailed explanation goes here
k = Constant.Boltzmann;
T = obj.temperature + 273.15 ; %celsius + 273 = kelvin
R = 50; %resistance of phdiode (50ohm is typical value)
% Magnitude squared detection
yout = sum( abs(xin) .^2*obj.responsivity,1) ;
% Shot Noise
shot_noise = sqrt(k * obj.fsimu .* yout) .* randn(1,size(yout,1));
yout = yout + shot_noise;
% Thermal Noise
therm_current_psd = (2 * k * T / R ) ; %squared
Bw = obj.fsimu; %is this correct? shouldnt it be the bandwidth of the actual component? e.g. 70GHz?
therm_noise_pow = therm_current_psd * 2 * Bw; %squared
therm_noise = sqrt(therm_noise_pow) .* randn(1,size(yout,1));
yout = yout + therm_noise;
% Dark Current
yout = yout + obj.dark_current ;
end
end
end

16
comm_tb.m
View File

@@ -16,7 +16,6 @@ kover = 16;
fsimu = kover * fdac ;
%SIMULATE
for i = 1:log2(M)
@@ -28,7 +27,6 @@ pamData = pam_mapping(bitpattern,M,0);
shapedData = applyPulseShaping(pamData,fsym,fdac);
awg = AWG('preset','M8196A','fdac',fdac,'kover',kover,'lpf_active',1);
awgSignal = awg.process_channel(shapedData);
@@ -43,7 +41,12 @@ laserfield = eml.process(filtered);
att = Amplifier("amplification_db",10,"amp_mode","gain","type","ideal","saturation_mode",0,'saturation_power',10);
att_out = att.process(laserfield);
%fib = Fiber("fiber_length",2,"alpha",0.2,"D",17,"lambda0",1550);
fib = Fiber("fsimu",fdac*kover,"fiber_length",20,"alpha",0.2,"D",17,"lambda0",1550);
fib_out = fib.process(att_out);
phdiode = Photodiode("fsimu",fdac*kover,"dark_current",2e-08,"responsivity",1,"temperature",20);
phdiod_out = phdiode.process(fib_out);
figure;
@@ -53,6 +56,7 @@ plot(awgSignal,'DisplayName','skew 0');
plot(filtered,'DisplayName','filtered');
plot(abs(laserfield),'DisplayName','laser');
plot(abs(att_out),'DisplayName','att_out');
plot(abs(fib_out),'DisplayName','att_out');
hold off
@@ -139,8 +143,4 @@ function yout = applyPulseShaping(xin,fsym,fdac)
warning('Check signal length after pulse shaping');
end
end
function yout = applyBandwidthLimitation(xin)
data_out=ifft(repmat(state.H,1,size(data_in,1)).*fft(data_in.')).';
end
end