solprop.tools

Design calculators: soliton numbers and dispersive-wave phase matching.

The numbers a person works out before a run. For a pulse of energy \(E\) and full width at half maximum \(\tau_{\rm fwhm}\) in a mode with group-velocity dispersion \(\beta_2\), effective area \(A_{\rm eff}\) and a fill of nonlinear index \(n_2\),

\[\gamma = \frac{n_2\omega_0}{cA_{\rm eff}},\quad L_D = \frac{\tau_0^2}{|\beta_2|},\quad L_{NL} = \frac{1}{\gamma P_0},\quad N = \sqrt{L_D/L_{NL}},\quad L_{\rm fiss} = L_D/N,\]

with the natural width \(\tau_0\) and the peak power \(P_0\) of the chosen pulse shape (pulse_width(), pulse_peak_power()). One shape runs through the whole chain, so the Gaussian numbers are never computed with a sech width.

A dispersive wave is phase matched to a soliton at the frequencies where

\[\Delta\beta(\omega) = \beta_{\rm dw}(\omega) - \beta_{\rm s}(\omega_0) - \beta_{1,\rm s}(\omega_0)(\omega-\omega_0) - k_{\rm NL}\]

vanishes (phase_mismatch()). The last term is the soliton’s nonlinear wavenumber and uses the largest unchirped constituent when pulse data are given (soliton_content()). Without pulse data the condition is linear. docs/guide/workflows/design-tools.md derives both and says what the nonlinear term assumes.

Everything is SI except pressure, which is in bar as at the rest of the user interface (docs/dev/conventions.md section 1).

Modules

beam	Free-space beam numbers: the critical power, beam parameters and intensities.
capillary	Soliton parameters of a mode or a gas-filled capillary, and capillary designs.
design	Design solvers: the parameter of a guide or fill that meets a design target.
phase_matching	Dispersive-wave phase matching: the mismatch and its roots in wavelength.
pulse	Pulse shape numbers: the natural width, peak power and energy of a pulse.
soliton	Soliton numbers: dispersion and nonlinear lengths, orders and constituents.
waveguide	The fill and the mode a design evaluates.