THz-bandwidth all-optical switching of heralded single photons

TL;DR

This paper demonstrates ultrafast all-optical switching of heralded single photons using the Kerr effect in fiber, achieving high efficiency and preservation of quantum states suitable for quantum photonics applications.

Contribution

It introduces a simple, high-bandwidth optical switching method for single photons that maintains quantum state integrity, using low pump energies and commercially available fiber.

Findings

97% switching efficiency achieved

Switching time of approximately 1.7 ps

Quantum state preservation confirmed by autocorrelation measurements

Abstract

Optically induced ultrafast switching of single photons is demonstrated by rotating the photon polarization via the Kerr effect in a commercially available single mode fiber. A switching efficiency of 97\% is achieved with a $\sim1.7$\,ps switching time, and signal-to-noise ratio of $\sim800$. Preservation of the quantum state is confirmed by measuring no significant increase in the second-order autocorrelation function $g^{(2)}(0)$. These values are attained with only nanojoule level pump energies that are produced by a laser oscillator with 80\,MHz repetition rate. The results highlight a simple switching device capable of both high-bandwidth operations and preservation of single-photon properties for applications in photonic quantum processing and ultrafast time-gating or switching.