1480 nm diode-pumped sub-kHz single-frequency Er-doped fiber laser at 1600.05 nm

This study successfully realized a single-frequency erbium-doped fiber laser operating at 1600.05 nm by harnessing fiber-based saturable absorber filtering effects. To mitigate adverse impacts of the fiber-based saturable absorber's length on laser loss, threshold, and cost, suitable fiber components were meticulously selected, facilitating the achievement of both single-frequency laser output and the desired power level. Spectral and frequency analysis revealed that the resultant single-frequency fiber laser demonstrates a specific power output range, with a maximum output power exceeding 10 mW. The average linewidth, measured using the delayed self-heterodyne method, was approximately 679.8 Hz, validated by the perfect Lorentz linear signal. During one hour of stability monitoring, the wavelength and power fluctuations were observed to be 1.51 pm and 0.082 %, respectively. Furthermore, we meticulously observe and quantify the laser spectrum and power dynamics during the experiment, and contrast the outcomes of various linewidth signals. This approach offers a novel perspective for observing and expressing the parameters of narrow linewidth lasers, particularly those equipped with extended fiber cavities.