# Distillation of Squeezing using a pulsed engineered PDC source

## TL;DR

This paper demonstrates a method to enhance the squeezing of pulsed quantum states using photon subtraction from a single-mode PDC source, improving quantum network capabilities.

## Contribution

It introduces a novel distillation technique for pulsed squeezed states from a single-mode PDC source without optical filtering, enhancing squeezing and purity.

## Key findings

- Achieved a 0.17 dB improvement in squeezing after distillation.
- Confirmed non-Gaussianity of the distilled states.
- Demonstrated source suitability for scalable hybrid quantum networks.

## Abstract

Hybrid quantum information processing combines the advantages of discrete and continues variable protocols by realizing protocols consisting of photon counting and homodyne measurements. However, the mode structure of pulsed sources and the properties of the detection schemes often require the use optical filters in order to combine both detection methods in a common experiment. This limits the efficiency and the overall achievable squeezing of the experiment. In our work, we use photon subtraction to implement the distillation of pulsed squeezed states originating from a genuinely spatially and temporally single-mode parametric down-conversion source in non-linear waveguides. Due to the distillation, we witness an improvement of $0.17~\mathrm{dB}$ from an initial squeezing value of $-1.648 \pm 0.002~\mathrm{dB}$, while achieving a purity of $0.58$, and confirm the non-Gaussianity of the distilled state via the higher-order cumulants. With this, we demonstrate the source's suitability for scalable hybrid quantum network applications with pulsed quantum light.