From ultra-noisy to ultra-stable: optimization of the optoelectronic laser lock

Published

August 24, 2025

Author(s)

Takuma Nakamura, Yifan Liu, Naijun Jin, Haotian Cheng, Charles McLemore, Nazanin Hoghooghi, Peter Rakich, Franklyn Quinlan

Abstract

We demonstrate thermal noise-limited direct locking of a semiconductor DFB laser to a sub-1 mL volume, ultrastable optical cavity, enabling extremely compact and simple ultrastable laser systems. Using the optoelectronic laser locking method, we realize over 140 dB suppression of the DFB free-running laser noise at 10 Hz offset, a level we estimate to be 70 dB greater than Pound-Drever-Hall locking can provide, and reach a phase noise level of -120 dBc/Hz at 200 kHz offset. We also demonstrate a new feedforward noise correction method that improves the quality of the heterodyne beat with an optical frequency comb by providing another 60 dB of laser noise rejection – a level that is 15 dB greater than predicted by current models. With feedforward, we transfer the cavity thermal noise limit across the comb spectrum despite the fact that the cavity-locked laser itself is noisy. These results establish a simple, low noise, compact approach to ultrastable laser locking that is compatible with integrated photonics, with applications in low phase noise microwave generation, sensing and satellite ranging.

Citation

Optica

Pub Type

Journals

Citation

Nakamura, T. , Liu, Y. , Jin, N. , Cheng, H. , McLemore, C. , Hoghooghi, N. , Rakich, P. and Quinlan, F. (2025), From ultra-noisy to ultra-stable: optimization of the optoelectronic laser lock, Optica (Accessed September 26, 2025)