Double-cladding thulium-doped all-fiber ultrafast laser based on nonlinear polarization rotation mode locking

Abstract

The invention discloses a double-cladding thulium-doped all-fiber ultrafast laser based on nonlinear polarization rotation mode locking and relates to a laser. By single-mode passive optical fibers, a beam combiner, a double-cladding thulium-doped fiber, an isolator, a polarized controller, an optical coupler and a polarizer are sequentially connected to form an annular optical-fiber resonance cavity, a pumping source injects pumping light into the annular optical-fiber resonance cavity through a pumping light input port of the beam combiner, and resonance is made in an output cavity of the output end of an optical coupler to generate soliton laser pulse. By adjustment of the polarized controller, double refraction in the cavity is changed to realize optical soliton pulse output, pulse width is 1.6 ps, pulse energy is 80 pj, pulse repetition frequency is 15MHz, 3dB band width is 4.45 nm, and the central wavelength is 2042 nm. In a 2-micrometer all-fiber laser, output of optical soliton pulse is realized.

Description

technical field [0001] The invention relates to a laser, in particular to a double-clad thulium-doped all-fiber ultrafast laser based on nonlinear polarization rotation mode-locking. Background technique [0002] Optical soliton refers to the wave packet that remains unchanged due to the balance between nonlinear effects and linear effects during medium transmission. Previously reported soliton fiber lasers are very sensitive to environmental changes due to the inclusion of free-space optical elements, and the use of an all-fiber structure overcomes this shortcoming. ([1] 8. L. E. Nelson, E. P. Ippen, and H. A. Haus, “Broadly tunable sub-500 fs pulses from an additive-pulse mode-locked thulium-doped fiber ring laser,” Appl. Phys. Lett. 67(1) , 19–21 (1995).). Using a double-clad gain fiber, a semiconductor laser can be used instead of an erbium-doped fiber amplifier (EDFA) as a pump source, which simplifies the cavity design and improves the light-to-light conversion effic...

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Problems solved by technology

[0005] Research on all-fiber ultrafast lasers based on nonlinear polarization rotation technology in the 1.5 μm band has been reported ([3] Dingyuan Tang. Mechanism of multisoliton formation and soliton energy quantization in passively mode-locked fiber lasers[J]. Physical Review A, 2005, 72(4):043816), but the double-clad gain fiber all-fiber structure mode-locked soliton based on nonlinear polarization rotation technology in the 2 μm band has not yet been published in the literature

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