A 1625 nm Q‐Switched All‐Fiber Laser

• Published in: Advanced photonics research Vol. 3; no. 3
• Main Authors: Cheng, Huihui, Huang, Xiaoyi, Jiang, Min, Yang, Jiahua, Lin, Liting, Li, Ting, Cai, Zhiping, Zhou, Shifeng
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley & Sons, Inc 01-03-2022; Wiley-VCH
• Subjects: Bandwidths; Electrons; element hybridization; erbium dopant; glass fibers; Lasers; Q-switched lasers; Spectrum allocation
• ISSN: 2699-9293; 2699-9293
• DOI: 10.1002/adpr.202100320

A Q‐switched all‐fiber Er‐doped laser operated at a wavelength up to 1625 nm is proposed and demonstrated. A self‐developed, element hybridization (Al, Ge, La, P, and Er in the core, Si and P in the cladding region) glass fiber with gain extended to U‐band is employed as gain medium. The compact laser cavity contains a fiber Bragg grating which was manufactured by means of point‐by‐point femtosecond laser inscription technique. Stable Q‐switched laser pulse train is successfully achieved using a semiconductor saturable absorber mirror at a low pump threshold of 29 mW. The laser has a maximum single pulse energy of 746 nJ and a minimum pulse duration of 26.8 μs. The pulse repetition rate can be gradually tuned from 6.47 to 11.87 kHz by increasing the pump power. In particular, the laser wavelength of the Q‐switched all‐fiber laser can be as long as 1625 nm. This is, to the best of our knowledge, the longest wavelength for the Q‐switched Er‐doped fiber lasers at this waveband.
The Q‐switched laser at wavelength of 1625 nm is required for CH4 or C2H4 gas detection. However, Q‐switched Er3+‐doped fiber laser with a wavelength longer than 1605 nm at near‐infrared waveband has been met with limited success. An element‐hybridization Er‐doped fiber that possess gain extended to U‐band is manufactured, and a Q‐switched laser operated at 1625 nm with excellent performance is further demonstrated.