Probing spectral-temporal correlations with a versatile integrated source of parametric down-conversion states

TL;DR

This paper demonstrates an integrated parametric down-conversion source capable of generating biphotons with various spectral-temporal correlations, revealing that correlation time depends solely on waveguide properties, not pump coherence.

Contribution

It introduces a versatile integrated PDC source for probing spectral-temporal correlations and clarifies the factors determining biphoton correlation time.

Findings

Correlation time is independent of pump coherence.

Correlation time depends only on waveguide length and dispersion.

Different spectral-temporal correlations are suitable for quantum applications.

Abstract

The spectral-temporal correlation and the correlation time of a biphoton wavepacket generated in the process of parametric down-conversion (PDC), is of great importance for a broad range of quantum experiments. We utilise an integrated PDC source to generate biphotons with different types of spectral-temporal correlations and probe their respective correlation times. The outcomes confirms that the correlation time is independent of the coherence time of the pump light, and it is only determined by the waveguide length and its dispersion properties. Furthermore, we investigate the properties of the PDC biphoton wavepacket exhibiting different types of spectral-temporal correlations and their suitability for quantum-enhanced applications.