Demonstration of $\bf3.5\times10^{-13}$ laser frequency stability at 1000 s using an iodine-filled hollow-core fiber photonic microcell

TL;DR

This paper demonstrates a highly stable laser frequency lock using an iodine-filled hollow-core fiber microcell, achieving record stability of 3.5×10⁻¹³ at 1000 seconds, surpassing previous gas-filled fiber references.

Contribution

The study introduces a novel iodine-filled hollow-core fiber microcell system with enhanced frequency stability and effective suppression of parasitic interference, achieving record stability levels.

Findings

Achieved fractional frequency stability of 3.5×10⁻¹³ at 1000 s

Identified and suppressed parasitic interference sources

Set a new benchmark for gas-filled hollow-core fiber frequency references

Abstract

We present a laser frequency stabilization system based on an iodine-filled hollow-core photonic microcell (PMC), which is a sealed version of a hollow-core photonic crystal fiber (HC-PCF). A 532 nm laser is locked to the a1 component of the R(56) 32-0 transition of molecular iodine in the fiber cell, and its frequency stability is compared to that of the same component in a free-space iodine cell. Noise analysis reveals that the system is limited by parasitic beams that interfere with the beam of interest and degrade the error signal. We have identified and characterized three types of parasitic interference and designed suppression methods for each. After applying these suppression methods, the frequency stability improved by more than an order of magnitude. The system achieves fractional frequency stability of $3.5\times10^{-13}$ for integration times around 1000 s. To our knowledge, this represents the best frequency stability achieved using a gas-filled hollow-core photonic crystal fiber frequency reference.