4099f6820f
WDM code added (Pol Cont., Opt MUX/DEMUX, Opt Atten, DP_Fiber) -> the codebase is not optimized to always work with dp signals!
33 lines
1.1 KiB
Matlab
33 lines
1.1 KiB
Matlab
%% Parameters
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df = linspace(100e3,50e6,10000); % Laser FWHM linewidth [Hz]
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n_fiber = 1.467; % Fiber group index
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c = 3e8; % Speed of light [m/s]
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% Compute coherence length (1/e of mean-fringe decay)
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tau_c = 1./(pi*df);
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L_c = (c/n_fiber) .* tau_c; % Coherence length [m]
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%% Plot
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figure('Color','w');
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loglog(df/1e6, L_c, 'LineWidth',2,'LineStyle','-'); % linewidth in MHz
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xticks([0.1, 1, 10, 50]);
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yticks([1, 10, 100, 1000]);
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yticklabels({'1','10','100','1000'})
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grid on; box on;
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xlabel('Laser linewidth [MHz]','FontSize',12,'Interpreter','none');
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ylabel('Coherence length [m]','FontSize',12,'Interpreter','none');
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title('Coherence Length vs. Laser Linewidth','FontSize',14,'Interpreter','none');
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%% Annotate some key points
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hold on;
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freqs = [150e3, 1e6, 10e6, 50e6]; % [Hz]
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for f = freqs
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x = f/1e6;
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y = (c/n_fiber) * (1/(pi*f));
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scatter(x,y,'Marker','x','LineWidth',1,'MarkerEdgeColor','black');
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text(x*1.1,y, sprintf('%.2f MHz', f/1e6), ...
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'FontSize',10,'HorizontalAlignment','left');
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end
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