Programmable Silicon Photonic Optical Thresholder

We experimentally demonstrate an all-optical programmable thresholder on a silicon photonic circuit. By exploiting the nonlinearities in a resonator-assisted Mach-Zehnder interferometer (MZI), the proposed optical thresholder can discriminate two optical signals with a power contract ratio as low as 1.13. We experimentally achieve a signal contrast enhancement of 40, which leads to a bit error rate (BER) improvement by 5 orders of magnitude and a receiver sensitivity improvement of 11 dB. We present the thresholding function of our device and validate the function with experimental data. Furthermore, we investigate potential device speed improvement by reducing the carrier lifetime.