Noise Filtering for Highly Correlated Photon Pairs from Silicon Waveguides

Abstract

We fabricate silicon waveguide spirals and a ring resonator to generate photon pairs based on a spontaneous four-wave mixing. The coincidence-to-accidental-ratio (CAR) of photon pairs from the silicon waveguides is measured up to 400 after a noise-filtering by using the combination of bandpass filters and pump-rejection filters. The CAR is enhanced up to 700 by adding on-chip pump-rejection MZIs. We observe the CAR of the photon pairs from a silicon spiral is highly depending on the wavelength detuning from the pump wavelength. We discuss the noise sources related to the degradation of the CAR based on our experimental results.