Fast and simple characterization of a photon pair source

TL;DR

This paper introduces an exact, fast, and simple model for characterizing photon pair sources, enabling precise measurement of source brightness and transmission, validated through experiments with a nonlinear crystal source.

Contribution

The paper presents a novel exact model for photon pair source detection statistics that improves measurement speed and accuracy for quantum communication applications.

Findings

Validated model accurately predicts $g^{(2)}(0)$ over wide brightness range

Enables real-time monitoring and tuning of source brightness

Applicable to sources with spectral/spatial filtering

Abstract

We present an exact model of the detection statistics of a probabilistic source of photon pairs from which a fast, simple and precise method to measure the source's brightness and photon channel transmissions is demonstrated. We measure such properties for a source based on spontaneous parametric downconversion in a periodically poled LiNbO$_3$ crystal producing pairs at 810 and 1550 nm wavelengths. We further validate the model by comparing the predicted and measured values for the $g^{(2)}(0)$ of a heralded single photon source over a wide range of the brightness. Our model is of particular use for monitoring and tuning the brightness on demand as required for various quantum communication applications. We comment on its applicability to sources involving spectral and/or spatial filtering.