GHz-rate positive conversion efficiency via FWM in multi-layer SiNx/a-Si:H waveguides

We demonstrate high-speed positive FWM conversion efficiency (CE) at 1-GHz repetition rate in a multi-layer platform of SiNx/a-Si:H waveguides. Positive CE is first measured at a peak pump power of 2-W, with up to 5-dB positive CE (corresponding to 6.2-dB of signal gain) at 3.35-W.