We present an all-fiber dual-wavelength holmium-doped fiber laser operating in 2μm region using a newly developed holmium-doped fiber (HDF) as a gain medium. The proposed fiber laser is constructed by using a hybrid gain medium, i.e., a thulium–ytterbium co-doped fiber (TYDF) and an HDF in conjunction with a simple half-opened linear cavity, which is formed by a broadband mirror and an output coupler reflector. Without the HDF, the TYDF laser operates at wavelengths of 1991 and 1999 nm with a signal-to-noise ratio of more than 34 dB and the slope efficiency of 26.16 %. With the HDF, dual-wavelength output lines are obtained at 2075 and 2083nm with signal-to-noise ratios of more than 17dB, 3 dB bandwidth of less than 0.2 nm and the power difference between the two peaks of less than 1 dB at the TYDF laser pump power of 320 mW.
Abstract. We investigate the lasing performance of a new double-clad thulium/ytterbium co-doped octagonal-shaped fibre, basing on a cladding pump technique. The fibre is fabricated with the aid of a modified chemical vapour deposition combined with a solution doping technique. It is characterized by the Tm 3+ -and Yb
3+-cladding absorptions equal to 0.325 and 3.3 dB/m respectively at 790 and 976 nm. A triple-wavelength fibre laser operating at 1914.5, 1934.7 and 1953.6 nm is built that uses a 5 m long fibre in a ring configuration as a gain medium. With the fibre as long as 15 m, the ring laser produces the highest output power of 21.9 mW at the pump power of 3600 mW, with the lowest threshold pump power being equal to 1000 mW. When operating at 1961.4 nm, the maximal efficiency of 0.88 per cent is achieved for the gain medium length fixed at 10 m. We also demonstrate a Q-switched thulium/ytterbium-doped fibre laser that operates at 1977.5 nm and utilizes multi-walled carbon nanotubes as a gain medium. By varying the multimode 905 nm pump power from 1591.3 to 2261.5 mW, one can increase the pulse repetition rate from 18.8 to 50.6 kHz, while the pulse width then decreases from 8.6 to 1.0 µs. The maximum pulse energy 5.71 nJ is obtained at the pump power 2100 mW.
In this paper, we experimentally demonstrate a stable passive Q-switched fiber laser operating at 1543.5 nm using a double clad Erbium-Ytterbium co-doped fiber (EYDF) as the gain medium in conjunction with nonlinear polarization rotation (NPR) technique. An isolator is used in conjunction with a highly nonlinear EYDF to induce intensity dependent loss in a sufficiently-high loss ring cavity to achieve Q-switched operation with a low pump threshold of 300 mW. At 980 nm multimode pump power of 500 mW, the EYDF laser generates an optical pulse train with a repetition rate of 46.95 kHz, pulse width of 5.3 µs and pulse energy of 75.6 nJ. The simple and inexpensive Q-switched NPRbased laser has a big potential for applications in metrology, environmental sensing and biomedical diagnostics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.