Compact Fiber-Coupled Narrowband Two-Mode Squeezed Light Source

TL;DR

This paper presents a compact, fiber-coupled, narrowband two-mode squeezed light source at 795 nm using four wave mixing in rubidium vapor, optimized for quantum sensing and networking applications.

Contribution

It introduces a small, modular fiber-coupled system generating two-mode squeezed states with low pump power and high squeezing, suitable for atomic quantum memories.

Findings

Achieved 4.4 dB intensity-difference squeezing at 1 MHz

Designed a compact, fiber-coupled, narrowband source at 795 nm

Optimized for low pump power (135 mW) and atomic quantum applications

Abstract

Quantum correlated states of light, such as squeezed states, are a fundamental resource for the development of quantum technologies, as they are needed for applications in quantum metrology, quantum computation, and quantum communications. It is thus critical to develop compact, efficient, and robust sources to generate such states. Here we report on a compact, narrowband, fiber-coupled source of two-mode squeezed states of light at 795 nm based on four wave mixing (FWM) in a $^{85}$Rb atomic vapor. The source is designed in a small modular form factor, with two input fiber-coupled beams, the seed and pump beams required for the FWM, and two output fibers, one for each of the modes of the squeezed state. The system is optimized for low pump power (135 mW) to achieve a maximum intensity-difference squeezing of 4.4 dB after the output fibers at an analysis frequency of 1 MHz. The narrowband nature of the source makes it ideal for atomic-based quantum sensing and quantum networking configurations that rely on atomic quantum memories. Such a source paves the way for a versatile and portable platform for applications in quantum information science.