Broadband Fiber-based Entangled Photon Pair Source at Telecom O-band

TL;DR

This paper presents a broadband, polarization-entangled photon-pair source at telecom O-band using periodically poled silica fiber, achieving record bandwidth and high entanglement fidelity suitable for quantum communication.

Contribution

It introduces the first broadband entangled photon source at O-band based on PPSF with over 130 nm bandwidth and high entanglement fidelity, advancing quantum communication technology.

Findings

Over 130 nm emission bandwidth centered at 1306.6 nm.

Hong-Ou-Mandel interference dip with 26.6 fs width.

Entanglement fidelity exceeds 95.4%.

Abstract

In this letter, we report a polarization-entangled photon-pair source based on type-II spontaneous parametric down conversion at telecom O-band in periodically poled silica fiber (PPSF). The photon-pair source exhibits more than 130 nm (~24 THz) emission bandwidth centered at 1306.6 nm. The broad emission spectrum results in a short biphoton correlation time and we experimentally demonstrate a Hong-Ou-Mandel interference dip with a full width of 26.6 fs at half maximum. Owing to the low birefringence of the PPSF, the biphotons generated from type-II SPDC are polarization-entangled over the entire emission bandwidth, with a measured fidelity to a maximally entangled state greater than 95.4%. The biphoton source provides the broadest bandwidth entangled biphotons at O-band to our knowledge.