Frequency tripled 1542 nm telecom laser diode stabilized to iodine hyperfine line in the 10-15 range

TL;DR

This paper demonstrates a highly efficient frequency tripling process for a telecom laser diode stabilized to an iodine hyperfine line, achieving high power green output and exceptional frequency stability suitable for space applications.

Contribution

It reports the best CW frequency tripling efficiency to date and a compact, fibered setup for laser stabilization using iodine hyperfine lines.

Findings

Green output power up to 300 mW with 36% efficiency

Frequency stability of 4.8x10^-14 at 1/2 s

Compact fibered optical setup suitable for space use

Abstract

We report on telecom laser frequency stabilization to narrow iodine hyperfine line in the green range of the optical domain, after a frequency tripling process using two nonlinear PPLN crystals. We have generated up to 300 mW optical power in the green (P3w), from 800 mW of infrared power (Pw). This result corresponds to an optical conversion efficiency eta= P3w/Pw ~ 36 %. To our knowledge, this is the best value ever demonstrated for a CW frequency tripling process. We have used a narrow linewidth iodine hyperfine line (component a1 of the 127I2 R 35 (44-0) line) to stabilize the IR laser yielding to frequency stability of 4.8x10-14 t-1/2 with a minimum of 6x10-15 reached after 50 s of integration time. The whole optical setup is very compact and mostly optically fibered. This approach opens the way for efficient and elegant architecture development for space applications as one of several potential uses.