Optically locked low-noise photonic microwave oscillator

TL;DR

This paper presents a compact, low-noise photonic microwave oscillator operating at 10.4 GHz, achieved through optical locking and integrated photonic components, promising for field-deployable sensing and communication.

Contribution

It introduces a novel optically locked microwave oscillator with integrated optical components, significantly reducing size and noise for practical applications.

Findings

Achieved phase noise of -54 dBc/Hz at 10 Hz offset

Packaged the system within 166 mL module

Demonstrated high-performance low-noise microwave generation

Abstract

The next-generation sensing and communication applications rely on high-frequency microwave generation with low-noise. The microwave photonic technology is promising by the practical application is limited by its complex architecture so far. Here, we demonstrate an optically locked low-noise photonic microwave oscillator, so that all the optical components are packaged within a small module of 166 mL, and low noise microwave generation is achieved at 10.4 GHz with single-sideband phase noise of -54 dBc/Hz at 10 Hz, -141 dBc/Hz at 10 kHz, and -162 dBc/Hz at 10 MHz offset. Above performance arises from a dual-laser self-injection-locking scheme to a single Fabry-Perot cavity with high Q exceeding 10^8, with over 20 dB common-mode noise suppression. The low-noise nature of such reference is coherently transferred to the X-band through a high-performance TFLN electro-optic comb chip, thereby overcoming long-standing barriers in photonic microwave integration to enable truly field-deployable low-noise microwave generation.