Mid-infrared pulsed lasers operating at the range of 2~20 μm have attracted substantial interests because of their widespread applications such as medical, spectroscopy, chemical, biomolecular sensing, defense, atmospheric, security and industrial machining. With the development of infrared glass fiber, mid-infrared fiber lasers are attracting increasing attention because they possess some inherent merits such as excellent beam quality, good heat dissipation, high efficiency and compact packaging compared to the other sources, though certainly, they cannot be regarded as a full replacement for the other lasers and rather provide complimentary capabilities. In this talk, I present our recent progress on CW and pulsed mid-infrared fiber lasers in the region of 2.7~4 μm. A series of rare-earth ions (i.e., Ho3+(~2.9 and ~3.9 μm), Dy3+(~3.1 μm), Er3+(~2.8 μm and ~3.5 μm) doped fluorides fibers were used to generate CW mid-infrared laser. Based on some new 2D/3D broadband nonlinear materials (e.g., black phosphorus, bismuth oxyselenide antimonene, cadmium arsenide, etc.), Q-switched and mode-locked pulses were generated in this mid-infrared region. Besides, gain-switching method was also adopted to generate short pulses at ~3 μm and ~3.5μm. At last, some discussions and prospective predictions are proposed.

Jianfeng Li (Outstanding Youth Foundation, IEEE senior member, EU Marie Curie International Incoming Fellow) received his BS degree in applied physics from Sichuan University in 2003, and MS and PhD degrees in Optical Engendering from Sichuan University in 2005 and 2008, respectively. Since 2008, he began to work in the School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC). In 2011, he joined the Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS) at University of Sydney as a visiting scientist. In 2013, he joined the Aston Institute of Photonic Technologies (AIPT) at the Aston University (UK) as a Marie Curie International Incoming Fellow funded by the European Commission's Seventh Framework Program (FP7). He has been promoted to a full professor at UESTC from 2015. His current research interests focus on mid-infrared fiber laser technology, ultrafast & nonlinear fiber optics, applications of mid-infrared fiber sources in medicine and nonlinear optics, fiber sensing, near-infrared spectroscopy detection technology. Until now, he has been responsible for more than 30 scientific research projects (including European Union's 7th Framework Program, National Natural Science Foundation of China, General Armament Department Project, etc.). He is current an editorial member of Scientific Reports and has published over 100 papers in peer-review journals and international conferences (including Nat. Commun., Adv. Mater., Photon. Res., Opt. Lett., Opt. Exp., IEEE J. Sel. Top. Quantum Electron., Sci. Rep., etc.).