Erasing Distinguishability Using Quantum Frequency Up-Conversion

TL;DR

This paper demonstrates erasing frequency distinguishability of two photons via quantum frequency up-conversion, enabling indistinguishability in quantum networks and improving photon-based quantum information processing.

Contribution

The authors experimentally show that frequency distinguishability can be erased using sum frequency generation, enhancing quantum networking capabilities.

Findings

Successful frequency indistinguishability erasure in single photons

Observation of non-classical Hong-Ou-Mandel interference dip

Potential for improved quantum communication systems

Abstract

The frequency distinguishability of two single photons was successfully erased using single photon frequency up-conversion. A frequency non-degenerate photon pair generated via spontaneous four-wave mixing in a dispersion shifted fiber was used to emulate two telecom-band single photons that were in the same temporal mode but in different frequency modes. The frequencies of these photons were converted to the same frequency by using the sum frequency generation process in periodically poled lithium niobate waveguides, while maintaining their temporal indistinguishability. As a result, the two converted photons exhibited a non-classical dip in a Hong-Ou-Mandel quantum interference experiment. The present scheme will add flexibility to networking quantum information systems that use photons with various wavelengths.