A Q-switched fibre laser operating in the 2 um region based on nonlinear polarization rotation technique

Abstract

Abstract. We demonstrate a Q-switched fibre laser operating at 1949.0 nm, which is based on a nonlinear polarization rotation (NPR) technique. It uses a 2 m long commercial thulium-doped fibre and a 15 m long homemade thulium-ytterbium codoped fibre as active media. They are pumped respectively by 800 nm single-mode and 905 nm multimode radiations. A stable Q-switched pulse train with the repetition rate 13.49 kHz and the pulse width 3.089 s is obtained when the 905 nm and 800 nm pump powers are fixed at 2.3 W and 110.4 mW, respectively. The maximum pulse energy, 11 nJ, is obtained at the 800 nm and 905 nm pump powers equal respectively to 110.4 mW and 2.5 W. To the best of our knowledge, this is the first reported Q-switched fibre laser using the NPR technique.

Passively Q-switched erbium-doped fiber laser based on Zn nanoparticles as a saturable absorber

“…Compared to actively Q-switched fiber lasers, passively Q-switched possess the advantages of simplicity, compactness, and flexibility in design. Passively Q-switched fiber lasers have been investigated using different kinds of SAs such as transition metal doped crystals [4][5][6][7], semiconductor saturable absorber mirrors (SESAMs) [8,9], nonlinear polarization rotation [10,11], and recently single-wall carbon nanotubes (SWNTs) [12][13][14]. Although the SWNTs require complex fabrication and expensive packing, they are often demanded for obtaining a broad wavelength range of saturable absorption [15].…”

Generation of Q-Switched Thulium-Doped Fiber Laser (Tdfl) Using Differentsaturable Absorbers

“…Q-switched fiber laser is of a great interest in laser technology for its ability to produce high energy pulse [17,18]. Q-switched fiber laser can be generated by both active and passive methods [7].…”

“…Besides using SAs for the pulse generation, there are other techniques that can be utilized for the application. Such technique that can be demonstrated is non-linear polarization rotation (NPR) [17,30]. In this technique, a so called artificial saturable absorption is created in the cavity that will induce the pulse generation.…”