Experimental study of Hong-Ou-Mandel interference using independent phase randomized weak coherent states

TL;DR

This paper experimentally investigates how various device imperfections affect Hong-Ou-Mandel interference visibility using independent phase randomized weak coherent states, providing a comprehensive model aligned with experimental data.

Contribution

It introduces a detailed model of imperfections affecting interference visibility and validates it through experimental measurements.

Findings

Visibility is sensitive to detector after-pulses and input mismatches.

Theoretical models accurately predict experimental interference visibility.

Imperfections can significantly reduce the ideal visibility of 0.5.

Abstract

Hong-Ou-Mandel interferometers are valuable tools in many Quantum Information and Quantum Optics applications that require photon indistinguishability. The theoretical limit for the Hong-Ou-Mandel visibility is 0.5 for indistinguishable weak coherent photon states, but several device imperfections may hinder achieving this value experimentally. In this work, we examine the dependence of the interference visibility on various factors, including (i) detector side imperfections due to after-pulses, (ii) mismatches in the intensities and states of polarization of the input signals, and (iii) the overall intensity of the input signals. We model all imperfections and show that theoretical modeling is in good agreement with experimental results.