Narrow-Linewidth Er-Doped Fiber Lasers With Random Distributed Feedback Provided By Artificial Rayleigh Scattering

• Published in: Journal of lightwave technology 2022-03, Vol.40 (6), p.1829-1835
• Main Authors: Skvortsov, Mikhail I., Wolf, Alexey A., Dostovalov, Alexandr V., Egorova, Olga N., Semjonov, Sergey L., Babin, Sergey A.
• Format: Article
• Language: English
• Subjects: Distributed feedback; Distributed feedback devices; Doped fibers; erbium; Erbium-doped fiber lasers; Fiber gratings; Fiber lasers; Insertion loss; Laser applications; Laser excitation; Laser feedback; Laser modes; Noise levels; Optical fibers; random; Rayleigh scattering; Signal to noise ratio; single-frequency; tunable
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2021.3116758

A compact random fiber laser based on a short artificial Rayleigh reflector and heavily-doped Er fibers (custom-made and commercial as a reference) has been proposed, characterized and optimized in terms of efficiency, linewidth and noise level. A 10-cm artificial Rayleigh reflector with mean scattering level of +41.3 dB/mm relative to the natural Rayleigh scattering of the host fiber and low insertion loss level (∼0.05 dB/cm at 1535 nm) was fabricated using a femtosecond direct writing technique. Its implementation as a distributed output mirror in a half-open cavity of a 980-nm diode pumped Er-doped fiber laser results in random lasing at 1535 nm in single- and few-mode regimes with power up to 100 mW, slope efficiency up to 16.5%, and signal-to-noise ratio up to 60 dB. A single-frequency regime with ∼10 KHz linewidth was observed at output power up to 2.5 mW. Tunability potential of such random lasers is also demonstrated.