Ultra-broadband photon pair preparation by spontaneous four wave mixing in dispersion-engineered optical fiber

TL;DR

This paper analyzes how to generate ultra-broadband, highly entangled photon pairs using spontaneous four wave mixing in dispersion-engineered optical fibers, highlighting conditions, fiber design, and a new quantum interference effect.

Contribution

It derives conditions for ultra-broadband photon pair generation in dispersion-engineered fibers and introduces a novel quantum interference effect with multiple spectral line pumping.

Findings

Photonic crystal fibers enable tailored ultra-broadband photon pair generation.

Conditions on pump frequencies and fiber dispersion are identified for broad spectral emission.

A new quantum interference effect from multiple spectral line pumping is demonstrated.

Abstract

We present a study of the spectral properties of photon pairs generated through the process of spontaneous four wave mixing (SFWM) in single mode fiber. Our analysis assumes narrowband pumps, which are allowed to be frequency-degenerate or non-degenerate. Based on this analysis, we derive conditions on the pump frequencies and on the fiber dispersion parameters which guarantee the generation of ultra-broadband photon pairs. Such photon pairs are characterized by: i) a very large degree of entanglement, and ii) a very high degree of temporal synchronization between the signal and idler photons. Through a numerical exercise, we find that the use of photonic crystal fiber (PCF) facilitates the fulfilment of the conditions for ultra-broadband photon pair generation; in particular, the spectral region in which emission occurs can be adjusted to particular needs through an appropriate choice of the PCF parameters. In addition, we present a novel quantum interference effect, resulting from indistinguishable pathways to the same outcome, which can occur when pumping a SFWM source with multiple spectral lines.