Tunable mode-locked laser based on femtosecond laser direct writing of long-period fiber gratings
LI Jiaxin
ZHANG Liqiang
YAO Yicun
SUO Yuman
WANG Minghong
Abstract：A wavelength-tunable mode-locked laser based on femtosecond laser direct writing of long-peri-od fiber gratings(LPFGs)is reported in this paper.Using a femtosecond laser,an LPFG with a period of 50 μm was inscribed,which exhibits a 3 dB bandwidth of 12.09 nm for its transmission peak near 1 032.67 nm.The LPFG was utilized as a filter in a ytterbium-doped fiber mode-locked laser,resulting in stable mode-locked pulses.By altering the refractive index of the surrounding medium,the transmission wave-length of the LPFG shifts accordingly.When the refractive index of the medium varies within the range of 1.40 to 1.43,the operating wavelength of the mode-locked laser is tunable from 1 046.42 nm to 1 060.25 nm,with a total tuning range of 13.83 nm.Compared to other wavelength tuning methods,the fiber grat-ing inscribed by femtosecond laser direct writing features a simple structure,flexible parameters,and ease of integration with fiber devices.
Keywords：mode-locked fiber laserfemtosecond laserlong-period fiber grating(LPFG)filteringwavelength-tunable
Publication Date：2025-12-31
Online Publishing Date：2026-08-28(First online date of this platform, not the publication date of the document)
Pages：11( 864-873,881 )