Single-Mode Squeezed Light Generation and Tomography with an Integrated Optical Parametric Oscillator

TL;DR

This paper presents a compact, chip-scale platform using a thin-film lithium niobate resonator to generate and measure squeezed light, advancing integrated quantum photonics with reduced size and complexity.

Contribution

The work introduces a monolithic integrated device that combines squeezed light generation and homodyne measurement on a single chip, overcoming previous limitations of integrated nonlinear photonics.

Findings

Achieved 0.55 dB squeezing and 1.55 dB anti-squeezing.

Generated pump field with 20 mW power via on-chip second harmonic generation.

Integrated all essential components except laser and detectors.

Abstract

Quantum optical technologies promise advances in sensing, computing, and communication. A key resource is squeezed light, where quantum noise is redistributed between optical quadratures. We introduce a monolithic, chip-scale platform that exploits the $\chi^{(2)}$ nonlinearity of a thin-film lithium niobate (TFLN) resonator device to efficiently generate squeezed states of light. Our system integrates all essential components -- except for the laser and two detectors -- on a single chip with an area of one square centimeter, significantly reducing the size, operational complexity, and power consumption associated with conventional setups. Our work addresses challenges that have limited previous integrated nonlinear photonic implementations that rely on either $\chi^{(3)}$ nonlinear resonators or on integrated waveguide $\chi^{(2)}$ parametric amplifiers. Using the balanced homodyne measurement subsystem that we implemented on the same chip, we measure a squeezing of 0.55 dB and an anti-squeezing of 1.55 dB. We use 20 mW of input power to generate the parametric oscillator pump field by employing second harmonic generation on the same chip. Our work represents a substantial step toward compact and efficient quantum optical systems posed to leverage the rapid advances in integrated nonlinear and quantum photonics.