Fiber Link Stabilization with a Multicore Fiber Amplifier

TL;DR

This paper demonstrates that multicore erbium-doped fiber amplifiers can significantly improve ultrastable optical frequency transfer, achieving extremely low frequency instability and advancing MCF networks for precision timing.

Contribution

It introduces the use of MC-EDFA cores in noise-canceled links, showing their potential for ultrastable frequency transfer in MCF networks.

Findings

Achieved fractional frequency instability of 5×10⁻¹⁹ at 1000 s with MC-EDFA alone.

Demonstrated 1.4×10⁻¹⁸ instability over 40 km with integrated fiber.

Established multicore fibers as promising for ultrastable frequency transfer.

Abstract

We study the use of separate cores of a multicore erbium-doped fiber amplifier (MC-EDFA) in a noise-canceled link for ultrastable optical frequency transfer. We demonstrate fractional frequency instability of $5\times10^{-19}$ at 1000 s averaging time for the stabilized MC-EDFA alone and $1.4\times10^{-18}$ at 1000 s averaging time when integrated with a 40 km-long 7-core spooled fiber. This study further establishes multicore fiber (MCF) networks as a promising platform for ultrastable frequency transfer, serving as an important step toward incorporating precision time and frequency distribution into future MCF communication infrastructures.