13dB Squeezed Vacuum States at 1550nm from 12mW external pump power at 775nm

TL;DR

This paper demonstrates the generation of 13dB squeezed vacuum states at 1550nm using only 12mW of pump power at 775nm, advancing quantum communication technology by reducing power requirements.

Contribution

It presents a novel method for achieving high-level squeezing at telecom wavelengths with significantly lower pump power in a doubly-resonant cavity setup.

Findings

Achieved 13dB squeezing at 1550nm with 12mW pump power.

Optimized cavity tuning methods for phase matching and resonance.

Projected reduction of pump power to 3mW with cavity improvements.

Abstract

Strongly squeezed light at telecommunication wavelengths is the necessary resource for one-sided device-independent quantum key distribution via fibre networks. Reducing the optical pump power that is required for its generation will advance this quantum technology towards efficient out-of-laboratory operation. Here, we investigate the second-harmonic pump power requirement for parametric generation of continuous-wave squeezed vacuum states at 1550nm in a state-of-the-art doubly-resonant standing-wave PPKTP cavity setup. We use coarse adjustment of the Gouy phase via the cavity length together with temperature fine-tuning for simultaneously achieving double resonance and (quasi) phase matching, and observe a squeeze factor of 13dB at 1550nm from just 12mW external pump power at 775nm. We anticipate that optimizing the cavity coupler reflectivity will reduce the external pump power to 3mW, without reducing the squeeze factor.