Performance evaluation of C/S-inter-band all-optical wavelength conversion in a thin-film PPLN waveguide based on a multichannel-signal DFG model

A multichannel-signal differential frequency generation (DFG) model is presented to analyze the all-optical wavelength conversion (AOWC) between C- and S-bands in a thin-film periodically poled lithium niobate (PPLN) waveguide. This model is established based on the nonlinear Schrödinger equation by considering a pulse-like broadband signal and pump. The thin-film PPLN waveguide is optimized to support broadband AOWC by engineering its propagation constants via the cross-section dimensions. In the optimized 443 nm wide thin-film PPLN waveguide, a conversion bandwidth of 248.2 nm can be numerically obtained when the waveguide length is 2.2 mm. By considering a multichannel signal and a single-frequency pump, the spectra of wavelength conversion are obtained using the multichannel-signal DFG model. A 61-channel wavelength conversion with a conversion efficiency (CE) of −2.8dB is achieved using a 24 dBm pump. Moreover, at most 117 signal channels can be supported if the CE threshold is set to be −10dB.