# Generation and measurement of a squeezed vacuum up to 100 MHz at 1550 nm with a semi-monolithic optical parametric oscillator designed towards direct coupling with waveguide modules

## TL;DR

This paper demonstrates a semi-monolithic optical parametric oscillator that generates a squeezed vacuum at 1550 nm up to 100 MHz, optimized for direct coupling with waveguide modules, achieving significant squeezing levels.

## Contribution

It introduces a novel OPO design with a flat output coupler enabling direct waveguide coupling, advancing integrated quantum optics applications.

## Key findings

- 6.2 dB squeezing at 2 MHz
- 3.0 dB squeezing at 100 MHz
- Operates at wavelength minimizing silica waveguide losses

## Abstract

We report generation and measurement of a squeezed vacuum from a semi-monolithic Fabry-Perot optical parametric oscillator (OPO) up to 100 MHz at 1550 nm. The output coupler of the OPO is a flat surface of a nonlinear crystal with partially reflecting coating, which enables direct coupling with waveguide modules. Using the OPO, we observed 6.2dB of squeezing at 2 MHz and 3.0 dB of squeezing at 100 MHz. The OPO operates at the optimal wavelength to minimize propagation losses in silica waveguides and looks towards solving a bottleneck of downsizing these experiments: that of coupling between a squeezer and a waveguide.