For the first time we have suggested and realized passive Q-switched cladding pumped Er-doped fiber laser with a saturable absorber based on Tm-doped fiber. The pulse duration was of 100 ns, the pulse energy -0.35 mJ, the peak power -3.5 kW while the average power is less than 1 W. The laser is perspective for technology processes and medicine. Key words: fiber laser and amplifier; Q-switching Q-switched fiber lasers due to high pulse energy allow one to increase a number of laser applications including medicine, material processing, range finding etc. Application of all-fiber design simplifies the laser collection and operation. One of the ways to realize all-fiber Q-switched laser consists in an application of the fiber saturable absorber. This approach utilizes an additional fiber having resonance losses at the oscillation wavelength within the laser cavity. Thus, Cr-doped fiber was used as absorber in Nd-doped fiber [1]. In [2,3] it was demonstrated that a placing of Sm-doped fiber in the cavity of Yb-doped fiber laser allows one to get the pulse generation occurring in extremely stable manner with pulse energy of approximately 20 μJ. A Q-switch pulse had a nearly perfect pulse shape with a ∼650 ns full width at half maximum (FWHM). The interesting approach was applied in [4], where Bi-doped fiber played a role of the saturated absorber. Bi-doped fiber was placed in a separate cavity to achieve a laser action at its wavelength and consequently to decrease the lifetime of the active centers in the excited state. That allowed authors to demonstrate the stable pulsed lasing with the pulse energy up to 0.1 mJ and the pulse duration in a range of approximately 1-2 μs. Application of this laser allowed us to demonstrate the pulsed Raman laser [5,6]. In [7,8] Q-switched Yb-doped fiber laser with Ho-fiber laser as the saturable absorber was demonstrated. Pulse energy was estimated as 70 μJ, peak power -as 300 W and pulse duration -250 ns. Thus several schemes for Q-switched Yb-doped fiber lasers were development.At the same time Q-switched Er-doped fiber lasers are of great interest because of their oscillation spectral range

For the first time to our best knowledge we have realized all-fiber supercontinuum source based on standard telecommunication multimode fiber. To pump the source Qswitched Er-doped fiber laser was used. The observed spectrum covers the spectral range from 1550 to 2400 nm with the power variation less than two decades. Average power of 0.85 W and pulse energy of 0.19 mJ was measured. Average power versus pump power for Q-switched Er-doped laser (1) and supercontinuum source (2)

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This letter is devoted to fabrication and tests of an optical fiber with a phosphate glass core in a silica cladding. The fiber preform was made by melting Yb, Er co-doped phosphate laser glass in a high-purity silica tube. 1.54 μm laser action was demonstrated under 1.06 μm pumping into the Yb absorption band.

We have proposed and demonstrated a new passively Q-switched thulium-doped fibre laser configuration. A distinctive feature of this configuration is the use of a heavily holmium-doped fibre for Q-switching. Lasing was obtained at 1.96 mm, with a pulse energy of 3 mJ and pulse duration of 600 ns. The highest pulse repetition rate was 80 kHz.