Open AccessSingle-frequency 1.7-μm Tm-doped fiber laser with optical bistability of both power and longitudinal mode behavior
Author(s) -
Junxiang Zhang,
Quan Sheng,
Lu Zhang,
Chaodu Shi,
Shuai Sun,
Xiaolei Bai,
Wei Shi,
Jianquan Yao
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.424336
Subject(s) - fiber laser , materials science , optics , laser linewidth , saturable absorption , longitudinal mode , laser , thulium , single mode optical fiber , optoelectronics , dispersion shifted fiber , bistability , polarization maintaining optical fiber , optical fiber , wavelength , doping , fiber optic sensor , physics
The single-frequency operation of a thulium fiber laser at a short wavelength of 1720 nm is investigated in a ring resonator. Powerful single-longitudinal-mode operation was realized by utilizing an unpumped thulium-doped fiber as the saturable absorber. The fiber laser delivered 407 mW single-frequency output with a spectral linewidth of 4.4 kHz under 2.7-W launched pump power at 1570 nm, which turned to multi-longitudinal-mode operation at higher pump powers. Additionally, optical bistability of both output power and longitudinal mode behavior, originating from the saturable absorption effect, were observed and discussed. To the best of our knowledge, this is the first efficient 1.7-μm single-frequency fiber laser as well as the first demonstration of optical bistability in thulium-doped fiber lasers.