Triple-Wavelength Thulium-Doped Fiber Random Laser Based on Random Fiber Grating
Lewen Zhou,
Yaozong Hu,
Wenlong Zheng,
Pengbai Xu,
Zhensen Gao,
Xinyong Dong
Affiliations
Lewen Zhou
Institute of Advanced Photonics Technology, School of Information Engineering, Guangdong Provincial Key Laboratory of Photonics Information Technology, Guangdong University of Technology, Guangzhou 510006, China
Yaozong Hu
Institute of Advanced Photonics Technology, School of Information Engineering, Guangdong Provincial Key Laboratory of Photonics Information Technology, Guangdong University of Technology, Guangzhou 510006, China
Wenlong Zheng
Institute of Advanced Photonics Technology, School of Information Engineering, Guangdong Provincial Key Laboratory of Photonics Information Technology, Guangdong University of Technology, Guangzhou 510006, China
Pengbai Xu
Institute of Advanced Photonics Technology, School of Information Engineering, Guangdong Provincial Key Laboratory of Photonics Information Technology, Guangdong University of Technology, Guangzhou 510006, China
Zhensen Gao
Institute of Advanced Photonics Technology, School of Information Engineering, Guangdong Provincial Key Laboratory of Photonics Information Technology, Guangdong University of Technology, Guangzhou 510006, China
Xinyong Dong
Institute of Advanced Photonics Technology, School of Information Engineering, Guangdong Provincial Key Laboratory of Photonics Information Technology, Guangdong University of Technology, Guangzhou 510006, China
We demonstrate a triple-wavelength thulium-doped fiber random laser using a 10 cm long random fiber grating to provide random distributed feedback and a superimposed fiber Bragg grating as the wavelength-selective mirror. The random fiber grating inscribed in single-mode fibers using a femtosecond laser provides strong random distributed feedback that avoids the use of long distance fibers and leads to a relatively low threshold power. Triple-wavelength random laser output at wavelengths of 1943.6, 1945.0 and 1946.3 nm was achieved with a relatively low threshold power of 2.01 W, a slope efficiency of 7.86% and a maximum output power of 151.8 mW when it was pumped using a 793 nm laser diode. The 3 dB linewidth was less than 0.1 nm and the optical signal-to-noise ratio was up to 45.6 dB. Good wavelength stability was achieved, which was attributed to the narrow band and stable reflection of the superimposed fiber Bragg grating. The time-domain characteristics of the laser output were also measured and analyzed, and some random self-pulsing caused by relaxation oscillations were observed.
