Medium

Medium{T<:Real}

Fiber medium parameters for GNLSE propagation.

Fields

• length::T: Propagation length [m]
• gamma::T: Nonlinear coefficient [1/(W·m)]
• loss::T: Loss factor [dB/m]
• dispersion::DispersionModel: Chromatic-dispersion model
• lambda0::T: Center wavelength [m]

Constructors

Medium(length, gamma, loss, betas::AbstractVector, lambda0)   # Taylor βₙ
Medium(length, gamma, loss, dispersion::DispersionModel, lambda0)
Medium(; length, gamma, loss=0.0, betas=(…), dispersion=(…), lambda0)

Notes

• Taylor betas exclude β₀ and β₁; betas[1] = β₂
• loss in dB/m converted to α = ln(10^(loss/10)) Np/m in the operator

Medium(; length, gamma, loss=0.0, betas=nothing, dispersion=nothing, lambda0)

Keyword constructor — avoids positional-argument mistakes. Supply the dispersion either as Taylor betas or as an explicit dispersion::DispersionModel (exactly one of the two).

BirefringentMedium(length, gamma, loss, dispersion_x, dispersion_y, deltabeta0, lambda0)

Birefringent fiber medium parameters for coupled vector GNLSE propagation.

Fields

• length::T: Propagation length [m]
• gamma::TG: Nonlinear coefficient γ [1/(W·m)]
• loss::T: Loss factor [dB/m]
• dispersion_x::DispersionModel: Dispersion model for x-polarization
• dispersion_y::DispersionModel: Dispersion model for y-polarization
• deltabeta0::T: Modal birefringence Δβ₀ [1/m] (difference in propagation constants β₀,x - β₀,y)
• lambda0::T: Center wavelength [m]

AmplifyingMedium(length, gamma, g0, Esat, noise_figure_db, loss, dispersion, lambda0)

Active rare-earth-doped amplifying fiber medium (EDFA, YDFA, TDFA) with gain saturation and ASE noise.

Fields

• length::T: Fiber length [m]
• gamma::TG: Nonlinear coefficient [1/(W·m)]
• g0::GD: Small-signal gain [1/m] (dB/m converted to Np/m: g_Np = ln(10^(g_dB/10)), or vector/function)
• Esat::T: Saturation energy [J]
• noise_figure_db::T: Amplifier Noise Figure [dB] (default: 4.0 dB)
• loss::TL: Background loss factor [dB/m] (scalar, vector, or function)
• dispersion::DispersionModel: Chromatic dispersion model
• lambda0::T: Center wavelength [m]

SemiconductorMedium(; length, gamma, alpha2, Aeff, sigma_fca, k_fcr, tau_c, loss, dispersion, lambda0)

Semiconductor waveguide medium (Silicon-on-Insulator SOI, Germanium, GaAs) with Two-Photon Absorption (TPA) and Free-Carrier Dynamics (FCA, FCR, lifetime τ_c).

Fields

• length::T: Waveguide length [m]
• gamma::TG: Kerr nonlinear coefficient [1/(W·m)]
• alpha2::T: Two-photon absorption coefficient α₂ [m/W]
• Aeff::T: Effective mode area A_eff [m²]
• sigma_fca::T: Free-carrier absorption cross section σ_FCA [m²] (default: 1.45e-21 m² for Si at 1550 nm)
• k_fcr::T: Free-carrier refraction coefficient k_FCR [m³] (default: 5.3e-27 m³ for Si at 1550 nm)
• tau_c::T: Free-carrier recombination lifetime τ_c [s] (default: 1.0e-9 s)
• loss::T: Linear background attenuation α₀ [dB/m]
• dispersion::DispersionModel: Chromatic dispersion model
• lambda0::T: Center wavelength [m]