Simple and compact diode laser system stabilized to Doppler-broadened iodine-lines at 633 nm

TL;DR

This paper introduces a compact, iodine-stabilized diode laser system at 633 nm with high stability, suitable for precision frequency standards, and compares its performance to primary Cs clocks using an optical frequency comb.

Contribution

The development of a small, stable iodine-stabilized laser system at 633 nm with detailed performance evaluation and modeling of stability across different iodine lines.

Findings

Fractional frequency instability below 10^{-10} for >10 s averaging time

System footprint of 27x15 cm^2 providing 5 mW output

Performance comparable to primary frequency standards

Abstract

We present a compact iodine-stabilized laser system at 633 nm, based on a distributed-feedback laser diode. Within a footprint of $27\times 15$ cm$^2$ the system provides 5 mW of frequency stabilized light from a single-mode fiber. Its performance was evaluated in comparison to Cs clocks representing primary frequency standards, realizing the SI unit Hz via an optical frequency comb. With the best suited absorption line the laser reaches a fractional frequency instability below $10^{-10}$ for averaging times above 10 s. The performance was investigated at several iodine lines and a model was developed to describe the observed stability on the different lines.