L- to U-Band Wavelength Conversion of QPSK Signals Using Intermodal Four-Wave Mixing

Efficient and broadband all-optical wavelength converters represent key components for the development of next-generation optical communications systems. We demonstrate here L- to U-band wavelength conversion of 50-Gbps quadrature phase-shift keying (QPSK) optical signals using a silicon-rich silicon nitride wavelength converter based on the Bragg scattering intermodal four-wave mixing effect. The U-band converted idlers were amplified using a custom-built counter-pumped U-band Raman amplifier. To the best of our knowledge, this represents the first demonstration of L- to U-band wavelength conversion of complex phase-coded communication signals.