Continuous wave photon pair generation in silicon-on-insulator waveguides and ring resonators

TL;DR

This paper investigates continuous wave photon pair generation in silicon-on-insulator waveguides and ring resonators, revealing new noise characteristics and demonstrating integrated on-chip sources with significantly enhanced spectral brightness.

Contribution

First demonstration of continuous wave photon pair generation in silicon waveguides, including integration with ring resonators and Sagnac interferometers, with improved spectral brightness.

Findings

Uncovered unexpected noise in continuous wave photon pair generation.

Achieved photon pair generation inside micro-ring cavities with 150 pm spectral width.

Enhanced spectral brightness by over two orders of magnitude.

Abstract

Silicon waveguides are promising $\chi^3$-based photon pair sources. Demonstrations so far have been based on picosecond pulsed lasers. Here, we present the first investigation of photon pair generation in silicon waveguides in a continuous regime. The source is characterized by coincidence measurements. We uncover the presence of unexpected noise which had not been noticed in earlier experiments. Subsequently, we present advances towards integration of the photon pair source with other components on the chip. This is demonstrated by photon pair generation in a Sagnac loop interferometer and inside a micro-ring cavity. Comparison with the straight waveguide shows that these are promising avenues for improving the source. In particular photon pair generation in the micro-ring cavity yields a source with a spectral width of approximately 150 pm resulting in a spectral brightness increased by more than 2 orders of magnitude.