% Parameters
c0    = physconst('lightspeed');      % [m/s]
lambda0 = 1310e-9;      % [m]
omega0  = 2*pi*c0/lambda0;

L     = 5e-3;           % [m] effective phase section length (set as needed)
n_eff = 2.2;            % [-] effective index (set as needed)

E0    = 1;              % field amplitude (arbitrary)
Vpi   = 3.2;            % [V] half-wave voltage (your V_pi)

% Drive
f0    = 1e9;            % [Hz]
fs    = 200e9;          % [Hz]
Nper  = 2;              % number of periods
Vpp   = 0.6*Vpi;        % [V] peak-to-peak of v_drive(t)

biasV = 1.1;            % [V] differential bias added to v_drive

% Time axis + differential drive voltage v_drive(t)
T  = Nper/f0;
t  = (0:1/fs:T-1/fs).';


if 1
    % SINE
    v_drive = biasV + (Vpp/2)*sin(2*pi*f0*t);  % v_drive(t) (peak = Vpp/2)

else

    % --- Generate PAM-4 Sequence ---
    symbols = linspace(-0.5, 0.5, 4);
    num_symbols = 12;                      % Increased slightly for better visual
    rng(44);
    random_data = symbols(randi(4, 1, num_symbols));

    % Create time axis (Note: T is your period from the sine code)
    sps = round(T * fs);
    t = (0:1/fs:(num_symbols*T)-1/fs).';

    % Upsample to rectangular waveform
    v_pam = repelem(random_data, sps).';

    % Apply swing and bias: Resulting range is [biasV-Vpp/2, biasV+Vpp/2]
    v_drive_rect = biasV + (v_pam * Vpp);

    % --- Round the edges ---
    filter_span = round(sps/1.5);          % Increased span for smoother "rounding"
    window = gausswin(filter_span);
    window = window / sum(window);

    % Apply filter (using 'same' to keep vector length, but be aware of edge transients)
    v_drive = conv(v_drive_rect, window, 'same');

end


% Analytic
v_ = linspace(-1,2, 2001);
% Field transfer function (amplitude)
Field_mzm_analytic = cos((pi/2)*v_);

% Power transfer function (intensity)
P_mzm_analytic = Field_mzm_analytic.^2;

% Imbalance factor in YOUR notation:
rho   = 1;   

% Push-pull branch voltages (consistent with v_drive = v1 - v2)
v1 = +0.5*v_drive;   % arm 1
v2 = -0.5*v_drive;   % arm 2

% Phases phi1, phi2
phi1 = pi * v1 / Vpi;
phi2 = pi * v2 / Vpi;

% Fields: E_in and E_out (exactly your Eq. (mzm_e_field))
E_in  = E0 .* exp(1i*omega0*t);

common_phase = exp(-1i * (omega0*L*n_eff/c0));  % exp(-j*omega0*L*n_eff/c0)

E_out = E0 .* exp(1i*omega0*t) .* common_phase .* 0.5 .* ...
        ( exp(-1i*phi1) + rho .* exp(-1i*phi2) );

% Transfer function (numerical): E_out/E_in
H_num = E_out ./ E_in;

% Power (normalized)
Pnorm_num   = abs(H_num).^2;     % since |E_out/E_in|^2

% Ideal TF (analytic) for comparison (rho=1, push-pull)
H_ideal = common_phase .* cos( (pi/2) * (v_drive./Vpi) );

Pnorm_ideal = abs(H_ideal).^2;
Pnorm_math = cos( (pi/2) * (v_drive./Vpi) ).^2;


set(groot, 'defaultLegendInterpreter', 'tex');
set(groot, 'defaultAxesTickLabelInterpreter', 'tex');
set(groot, 'defaultTextInterpreter', 'tex');

% Normalized voltage axis (multiples of Vpi)
v_norm = v_drive./Vpi;

colfield = [0,0,0]; %is black
colpow = linspecer(2);
colpow = colpow(1,:);
colvdrive = linspecer(2);
colvdrive = colvdrive(2,:);

%% SIGNAL IN
figure(1); clf
plot(v_norm,t*1e9, 'LineWidth', 1.0,'Color',colvdrive); grid on;
ylabel('t [ns]'); xlabel('v_{drive}(t)/V_\pi'); 
title('Drive voltage (normalized)');
xlim([min(v_) max(v_)]);
% mat2tikz_improved('C:\Users\Silas\Documents\6971e0b65b380ca6d71c837f\02_IMDD_System\tikz\linear_casee\mzm_input_signal.tex');


%% IN/OUT (static transfer) — normalized x-axis + analytic curve
if 0
figure(2); clf
plot(v_, Field_mzm_analytic, 'LineWidth', 1.2,'LineStyle','--','Color',colfield); hold on;% analytic power TF
plot(v_, P_mzm_analytic, 'LineWidth', 1.2, 'Color',colpow); hold on;% analytic power TF
% show input time signal
plot(v_norm,-1+t*1e9, 'LineWidth', 1.0,'Color',colvdrive); grid on;
% show output time signal
plot(2+t*1e9, Pnorm_num,   'LineWidth', 1.0,'DisplayName','Intensity', 'Color',colvdrive); hold on;
plot(2+t*1e9, real(H_ideal), '--', 'LineWidth', 1.0,'DisplayName','Field','Color',colfield); hold on;
scatter(v_norm, Pnorm_num, 12, '.', 'LineWidth', 1,'MarkerEdgeColor',colvdrive); 
scatter(biasV./Vpi,(cos((pi/2)*biasV./Vpi)^2),10,'Marker','o');
line([min(v_drive), min(v_drive)]./Vpi,[(cos((pi/2)*min(v_drive)./Vpi)^2), -2],'linewidth',0.5,'color','black','linestyle','--');
line([max(v_drive) max(v_drive)]./Vpi,[(cos((pi/2)*max(v_drive)./Vpi)^2), -2],'linewidth',0.5,'color','black','linestyle','--');
xline([min(v_norm) max(v_norm)])

grid on;
xlabel('v_{drive}(t)/V_\pi'); ylabel('|E_{out}/E_{in}|^2');
% legend
xlim([min(v_) max(v_)+1]);
ylim([-1 1]);

% mat2tikz_improved('C:\Users\Silas\Documents\6971e0b65b380ca6d71c837f\02_IMDD_System\tikz\mzm.tex');
end
%%

figure(3); clf
plot(v_, Field_mzm_analytic, 'LineWidth', 1.2,'LineStyle','--','Color',colfield); hold on;% analytic power TF
plot(v_, P_mzm_analytic, 'LineWidth', 1.2, 'Color',colpow); hold on;% analytic power TF

scatter(v_norm, Pnorm_num, 12, '.', 'LineWidth', 1,'MarkerEdgeColor',colvdrive); 
scatter(biasV./Vpi,(cos((pi/2)*biasV./Vpi)^2),10,'Marker','o');
line([min(v_drive), min(v_drive)]./Vpi,[(cos((pi/2)*min(v_drive)./Vpi)^2), -2],'linewidth',0.5,'color','black','linestyle','--');
line([max(v_drive) max(v_drive)]./Vpi,[(cos((pi/2)*max(v_drive)./Vpi)^2), -2],'linewidth',0.5,'color','black','linestyle','--');
xline([min(v_norm) max(v_norm)])

grid on;
xlabel('v_{drive}(t)/V_\pi'); ylabel('|E_{out}/E_{in}|^2');
% legend
xlim([min(v_) max(v_)]);
ylim([-1 1]);

% mat2tikz_improved('C:\Users\Silas\Documents\6971e0b65b380ca6d71c837f\02_IMDD_System\tikz\mzm_tramsfer_function_matlab.tex');


%% 

figure(4); clf
% plot(v_, Field_mzm_analytic, 'LineWidth', 1.2,'LineStyle','--','Color',colfield); hold on;% analytic power TF
plot(v_, P_mzm_analytic, 'LineWidth', 1.2, 'Color','black'); hold on;% analytic power TF
input_dots = linspace(min(v_drive),max(v_drive),4)./Vpi;
% input_dots = unique(v_drive_rect)./Vpi;
output_dots = (cos((pi/2)*input_dots).^2);
scatter(input_dots,output_dots,'Marker','x','LineWidth',1,'MarkerEdgeColor','black');
scatter(input_dots,zeros(size(input_dots)),'Marker','^','LineWidth',2,'MarkerEdgeColor','black');
% scatter(ones(size(input_dots)),output_dots,'Marker','<','LineWidth',2,'MarkerEdgeColor','black');

for i = 1:numel(input_dots)
    % Draw the dashed projection lines
    line([input_dots(i), input_dots(i)], [output_dots(i), 0], 'linewidth', 0.5, 'color', 'black', 'linestyle', '--', 'handlevisibility', 'off');
    line([input_dots(i), 1], [output_dots(i), output_dots(i)], 'linewidth', 0.5, 'color', 'black', 'linestyle', '--', 'handlevisibility', 'off');
    
    % Add the level annotation boxes near the output (y-axis)
    % Adjust the '1.05' to move the box further right or 'output_dots(i)' for height
    j = 3-(i-1)*2;
    text(1, output_dots(i), sprintf('Level %d', j), ...
        'FontSize', 8, ...
        'EdgeColor', 'black', ...
        'BackgroundColor', 'white', ...
        'Margin', 2);
end

xlim([0,1.5]);
ylim([0,1])

% line([min(v_drive), min(v_drive)]./Vpi,[(cos((pi/2)*min(v_drive)./Vpi)^2), 0],'linewidth',0.5,'color','black','linestyle','--');
% line([max(v_drive), max(v_drive)]./Vpi,[(cos((pi/2)*max(v_drive)./Vpi)^2), 0],'linewidth',0.5,'color','black','linestyle','--');

% mat2tikz_improved('C:\Users\Silas\Documents\6971e0b65b380ca6d71c837f\02_IMDD_System\tikz\linear_casee\mzm_tf.tex');
% xticks(sort(input_dots));
% yticks(sort(output_dots));
grid off


%% 
% % FIELD TF (only field here; do not mix power into this figure)
figure(5); clf
% plot(t*1e9, real(H_num), 'LineWidth', 1.0); hold on;
% plot(t*1e9, real(H_ideal), '--', 'LineWidth', 1.0,'DisplayName','Field','Color',colfield); hold on;
plot(t*1e9, Pnorm_num,   'LineWidth', 1.0,'DisplayName','Intensity', 'Color',colpow); hold on;
grid on;
xlabel('t [ns]'); ylabel('Re\{E_{out}/E_{in}\}');
legend
yticks(sort(output_dots));
% mat2tikz_improved('C:\Users\Silas\Documents\6971e0b65b380ca6d71c837f\02_IMDD_System\tikz\linear_casee\mzm_output_signal.tex');