Open AccessContinuously wavelength-tunable mode-locked Tm fiber laser using stretched SMF-GIMF-SMF structure as both saturable absorber and filter
Author(s) -
Huanhuan Li,
Fangming Hu,
Ying Tian,
Panting Wang,
Junjie Zhang,
Shiqing Xu
Publication year - 2019
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.27.014437
Subject(s) - optics , materials science , fiber laser , saturable absorption , multi mode optical fiber , laser , mode locking , band pass filter , wavelength , optoelectronics , optical fiber , physics
We demonstrate, for the first time, use of a stretched single mode-graded-index multimode-single mode fiber (SMF-GIMF-SMF) structure as a saturable absorber (SA) for a passively mode-locked Tm fiber laser. Such an all-fiber SA was based on the nonlinear multimode interference (NL-MMI). Stable fundamentally mode-locking operation was obtained at a pump threshold of 100mW. The output soliton pulses had a center wavelength, spectral width, pulse duration, and repetition rate of 1931 nm, 3.77 nm, 1.2ps, and 19.94 MHz, respectively. Furthermore, the SMF-GIMF-SMF structure can also be used as a filter to tune the laser. Continuously tunable mode-locking was experimentally demonstrated only by varying the stretched length of GIMF. Our results indicate that the stretched SMF-GIMF-SMF structure could serve as a SA together with a bandpass filter, which makes it advantageous for wavelength-tunable mode locking lasers.