Abstract
A novel mode-locking method based on the nonlinear multimode interference in the stretched graded-index multimode optical fiber (GIMF) is proposed in this Letter. The simple device geometry, where the light is coupled in and out of the stretched GIMF via single-mode fibers, is demonstrated to exhibit the temporal intensity discrimination required for mode locking. The nonlinear saturable absorber (SA) characteristics of the device are controllable by simply adjusting the strength of the stretching applied. The modulation depth of the device, which consists of GIMF, is tuned from 10.37% to 22.27%. Such a simple SA enables the wavelength-switchable mode-locking operation in a ring Er-doped fiber laser, and ultrafast pulses with a pulse width of 506 fs at 1572.5 nm and 416 fs at 1591.4 nm were generated. The versatility and simplicity of the SA device, together with the possibility of scaling the pulse energy, make it highly attractive in ultrafast photonics.
© 2018 Optical Society of America
Full Article | PDF ArticleMore Like This
Fan Yang, D. N. Wang, Zhaokun Wang, Liujiang Li, Chun-Liu Zhao, Ben Xu, Shangzhong Jin, Shi-Ying Cao, and Zhan-Jun Fang
Opt. Express 26(2) 927-934 (2018)
Xin Li, D. N. Wang, and Jikai Chen
J. Opt. Soc. Am. B 38(7) 2112-2117 (2021)
Sanfei Wang, D. N. Wang, and Ben Xu
Appl. Opt. 62(6) 1504-1509 (2023)