21 lines
632 B
Matlab
21 lines
632 B
Matlab
function deltaBeta = calcPhaseMatching(f_i, f_j, f_k, f_0, Ds)
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% Approximate phase mismatch for degenerate FWM close to the ZDW.
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% Inputs are frequencies in Hz.
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% f_i, f_j : pump frequencies (equal in the degenerate case)
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% f_k : signal frequency
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% f_0 : zero-dispersion frequency
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% Ds : dispersion slope in ps / (nm^2 km)
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c = physconst('LightSpeed');
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pump_frequency = 0.5 .* (f_i + f_j);
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lambda_zdw_m = c ./ f_0;
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dispersion_slope_si = Ds .* 1e3;
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deltaBeta = -(2 .* pi .* lambda_zdw_m.^4 ./ c.^2) .* ...
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dispersion_slope_si .* ...
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(pump_frequency - f_0) .* ...
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(pump_frequency - f_k).^2;
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end
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