Detection of carbon monoxide using a polarization-multiplexed erbium dual-comb fiber laser

TL;DR

This paper introduces a compact, polarization-multiplexed erbium dual-comb fiber laser that enables flexible, stable dual-comb spectroscopy of carbon monoxide without active stabilization, advancing portable gas sensing technologies.

Contribution

The work presents a novel all-polarization-maintaining erbium dual-comb laser with tunable repetition rate difference, suitable for stable, portable dual-comb spectroscopy applications.

Findings

Successful demonstration of CO detection using the laser

Achieved tunable difference in repetition rates from 500 Hz to 200 kHz

Operated without active stabilization, indicating system stability

Abstract

We present a compact, reliable, and robust free-running all-polarization-maintaining erbium (Er) single-cavity dual-comb laser generated via polarization multiplexing with gain sharing. Polarization multiplexing exploits the fast and slow axes of the fiber, while modelocking is achieved through a nonlinear amplifying loop mirror scheme using readily available components. The laser operates at a repetition rate of around 74.74 MHz with a tuning capability in the difference in repetition rates from 500 Hz to 200 kHz. This tunability makes the system more flexible for dual-comb spectroscopy experiments. Consequently, using this laser, we demonstrated a proof-of-principle dual-comb spectroscopy of carbon monoxide (CO), operating without any active stabilization.