A bright, pulsed two-mode squeezer

TL;DR

This paper reports the development of a bright, ultrafast two-mode squeezer in waveguides that generates entangled photon pairs with high squeezing levels, suitable for quantum communication in the telecom band.

Contribution

The authors demonstrate a novel, high-brightness two-mode squeezer based on PDC in waveguides, producing single-mode pulsed EPR states with significant squeezing.

Findings

Achieved mean photon number up to 2.5 per pulse

Demonstrated 11dB of two-mode squeezing

Confirmed single-mode character via $g^{(2)}$ correlation measurements

Abstract

We report the realization of a bright ultrafast two-mode squeezer based on type II parametric downconversion (PDC) in periodically poled $\mathrm{KTiOPO_4}$ (PP-KTP) waveguides. It produces a pulsed two-mode squeezed vacuum state: a photon-number entangled pair of truly single-mode pulses or, in terms of continuous variables quantum optics, a pulsed, single mode Einstein-Podolsky-Rosen (EPR) state in the telecom regime. We prove the single mode character of our source by measuring its $g^{(2)}$ correlation function and demonstrate a mean photon number of up to 2.5 per pulse, equivalent to 11dB of two-mode squeezing.