halfway merged and pulled?!

projects/ECOC_2025/theory/coherence_length_plot.m

@@ -0,0 +1,32 @@
+%% Parameters
+df       = linspace(1,50e6,10000);   % Laser FWHM linewidth [Hz]
+n_fiber  = 1.467;                      % Fiber group index
+c        = 3e8;                        % Speed of light [m/s]
+
+% Compute coherence length (1/e of mean-fringe decay)
+tau_c = 1./(pi*df);
+L_c   = (c.* tau_c/n_fiber) ;          % Coherence length [m]
+
+%% Plot
+figure('Color','w'); 
+loglog(df/1e6, L_c, 'LineWidth',2,'LineStyle','-'); % linewidth in MHz
+% xticks([0.1, 1, 10, 50]);
+% yticks([1, 10, 100, 1000]);
+% yticklabels({'1','10','100','1000'})
+grid on; box on;
+xlabel('Laser linewidth [MHz]','FontSize',12,'Interpreter','latex');
+ylabel('Coherence length [m]','FontSize',12,'Interpreter','latex');
+title('Coherence Length vs. Laser Linewidth','FontSize',14,'Interpreter','latex');
+
+%% Annotate some key points
+% hold on;
+% freqs = [150e3, 1e6, 10e6, 50e6]; % [Hz]
+% for f = freqs
+%     x = f/1e6;
+%     y = (c/n_fiber) * (1/(pi*f));
+%     scatter(x,y,'Marker','x','LineWidth',1,'MarkerEdgeColor','black');
+% 
+%     text(x*1.1,y, sprintf('%.2f MHz', f/1e6), ...
+%         'FontSize',10,'HorizontalAlignment','left');
+% 
+% end