# Ultra-low noise dual-frequency VECSEL at telecom wavelength using fully correlated pumping

## TL;DR

This paper demonstrates an ultra-low noise dual-frequency VECSEL at telecom wavelengths using fully correlated pumping, achieving near spontaneous emission limit noise levels and highlighting the impact of thermal effects on phase noise.

## Contribution

It introduces a fully correlated pumping scheme for dual-frequency VECSELs that significantly reduces intensity and phase noise at telecom wavelengths.

## Key findings

- Relative intensity noise below -140 dB/Hz
- Beatnote phase noise suppressed by 30 dB
- Thermal effects influence residual phase noise

## Abstract

An ultra-low intensity and beatnote phase noise dual-frequency vertical-external-cavity surface-emitting laser is built at telecom wavelength. The pump laser is realized by polarization combining two single-mode fibered laser diodes in a single-mode fiber, leading to a 100 % in-phase correlation of the pump noises for the two modes. The relative intensity noise is lower than -140 dB/Hz, and the beatnote phase noise is suppressed by 30 dB, getting close to the spontaneous emission limit. The role of the imperfect cancellation of the thermal effect resulting from unbalanced pumping of the two modes in the residual phase noise is evidenced.

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Source: https://tomesphere.com/paper/1812.04192