Spectrally Multiplexed Hong-Ou-Mandel Interference

TL;DR

This paper demonstrates spectrally-resolved Hong-Ou-Mandel interference using a VIPA-based spectral-to-spatial mode mapper, showing potential for quantum communication applications like quantum repeaters and Bell-state measurements.

Contribution

It introduces a spectrally-resolved HOM interference setup with high visibility, utilizing VIPA as a spectral-to-spatial mode mapper for quantum communication.

Findings

HOM dip observed with up to 45% visibility in spectral modes

Visibility drops significantly for unmatched spectral modes

Simulation shows potential for high-rate quantum key distribution

Abstract

We explore the suitability of a Virtually-Imaged Phased Array (VIPA) as a Spectral-to-Spatial Mode-Mapper (SSMM) for applications in quantum communication such as a quantum repeater. To this end we demonstrate spectrally-resolved two-photon "Hong-Ou-Mandel" (HOM) interference. Spectral sidebands are generated on a common optical carrier and weak coherent pulses are prepared in each spectral mode. The pulses are subsequently sent to a beamsplitter followed by two SSMMs and two single-photon detectors, allowing us to measure spectrally-resolved HOM interference. We show that the so-called HOM dip can be observed in the coincidence detection pattern of matching spectral modes with visibilities as high as 45% (with the maximum being 50%). For unmatched modes, the visibility drops significantly, as expected. Due to the similarity between HOM interference and a linear-optics Bell-state measurement (BSM), this establishes this simple optical arrangement as a candidate for the implementation of a spectrally-resolved BSM. Finally, we simulate the secret key generation rate using current and state-of-the-art parameters in a Measurement-Device Independent Quantum Key Distribution scenario and explore the trade-off between rate and complexity in the context of a spectrally-multiplexed quantum communication link.