Ultra-low noise laser and optical frequency comb-based timing system for the Black Hole Explorer (BHEX) mission

TL;DR

This paper presents a highly stable, space-qualified laser and optical frequency comb system designed to provide ultra-low noise timing for the Black Hole Explorer mission, enabling precise VLBI observations in space.

Contribution

It introduces a novel space-compatible timing system based on an ultra-low noise laser and optical frequency comb, tailored for space-based black hole observation missions.

Findings

System meets BHEX timing stability requirements

Demonstrated ultra-low noise performance in space-like conditions

Successful implementation of laser and comb transfer stability to microwave signals

Abstract

In this effort, we demonstrate the performance of a highly stable time reference for the proposed Black Hole Explorer (BHEX) mission, a space-based extension to the Event Horizon Telescope (EHT) Very Long Baseline Interferometry (VLBI) project. This precision timing system is based on the use of a space-qualified, ultra-low noise laser developed as part of the Laser Interferometer Space Antenna (LISA) mission as the timing reference, and an optical frequency comb to transfer the stability of this laser to the microwave regime for instrumentation use. We describe the implementation of this system and experimental setup to characterize the stability performance. We present the results of this experiment that demonstrate the performance of this system meets requirements for the BHEX mission.