WIP

Classes/Amplifier.m

@@ -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
 

Classes/Fiber.m

@@ -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.fsimu           = options.fsimu;
-            obj.alpha = options.alpha;
+            obj.fiber_length    = options.fiber_length*1000; %km
-            obj.D =options.D*1e-6;
+            obj.alpha           = options.alpha;
-            obj.Dslope =options.Dslope;
+            obj.D               = options.D*1e-6;
-            obj.lambda0 =options.lambda0;
+            obj.Dslope          = options.Dslope*1e3;
-            obj.gamma =options.gamma;
+            obj.lambda0         = options.lambda0*1e-9;
-            obj.dphimax =options.dphimax;
+            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
 
+
+
+
+
+
+
+
+
+
+
+
+
+
+

Classes/Photodiode.m

@@ -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
+

comm_tb.m

@@ -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
 
@@ -140,7 +144,3 @@ function yout = applyPulseShaping(xin,fsym,fdac)
     end
 
 end
-
-function yout = applyBandwidthLimitation(xin)
-    data_out=ifft(repmat(state.H,1,size(data_in,1)).*fft(data_in.')).';
-end