brillouin_gain_spectrum

photonforge.fiber.brillouin_gain_spectrum(detuning, *, brillouin_linewidth=20e6)

Normalised Brillouin gain, a Lorentzian centred on the Stokes shift.

\[g(\nu) = \frac{(\Delta\nu_B/2)^2} {(\nu - \nu_B)^2 + (\Delta\nu_B/2)^2}\]

Parameters:

• detuning (float | ndarray) – Offset from the Brillouin shift, in Hz.

• brillouin_linewidth (Annotated[float, exclusiveMinimum=0, units='Hz']) – Full width at half maximum, in Hz.

Returns:

Gain normalised to 1 at line centre.

Return type:

ndarray | float