Discrete Diffraction for Spectral Purification in Spontaneous Four Wave Mixing: a Recipe

TL;DR

This paper introduces a method using discrete diffraction in waveguide arrays to enhance spectral purity in spontaneous four wave mixing, achieving near-perfect purity in a silicon-on-insulator system.

Contribution

It presents a novel approach to control nonlinearity via discrete diffraction, improving spectral purity in photon pair generation.

Findings

Spectral purity improved from 0.78 to 0.97.

Method applicable to silicon-on-insulator waveguides.

Provides a design recipe for spectral purification.

Abstract

Linear discrete diffraction of light within a waveguide array allows control over the longitudinal spatial profile of light. We propose a method of using this control to effectively modulate the nonlinearity in a spontaneous four wave mixing system. This allows the removal spurious frequency correlations between the generated signal and idler photon pairs. Weaving our method into a recipe for waveguide design, we demonstrate a spectral purity improvement from P = 0.78 to near saturation at P = 0.97, for a simple silicon-on-insulator geometry.