Femtosecond laser direct-writing FBG array-based erbium-doped fiber laser

Abstract

The invention discloses a femtosecond laser direct-writing FBG array-based erbium-doped fiber laser. The femtosecond laser direct-writing FBG array-based erbium-doped fiber laser comprises a sensing fiber, wherein a wavelength division multiplexer, a C-band erbium-doped fiber, an L-band erbium-doped fiber, a polarization controller, a fiber circulator, a coupler, a pumping source, a spectrograph,an FBG array and a broadband reflecting mirror, wherein the FBG array is fabricated by a femtosecond laser direct-writing single-mode fiber, and three parallel FBG gratings are engraved on a fiber core of the single-mode fiber and are equal in length and different in reflection wavelength. Femtosecond laser is transmitted through a fiber protection layer, fiber Bragg gratings of which direct-writing periods are respectively 538 nanometers, 542 nanometers and 547 nanometers in the single-mode fiber without removing a coating layer are used as frequency selection devices, the C-band erbium-dopedfiber, the L-band erbium-doped fiber, the pumping source, the polarization controller and the broadband all reflecting mirror are combined to form a linear cavity fiber laser, single-wavelength and dual-wavelength laser output of which wavelengths can be switched is achieved, a side mode in a laser spectrum is prevented, and the wavelength stability is improved.

Description

technical field [0001] The invention relates to the field of optical fiber sensing, in particular to an erbium-doped fiber laser based on a femtosecond laser direct writing FBG array. Background technique [0002] Wavelength-tunable narrow-linewidth fiber lasers have the characteristics of compact structure, low loss, flexible and tunable wavelength, high signal-to-noise ratio, and narrow laser linewidth. Among them, erbium-doped fiber lasers cover the C+L band and can be widely used in optical communications, Laser radar, biomedicine, spectral analysis and other fields. Therefore, it has become a research hotspot in this field to carry out research on wavelength-tunable fiber lasers in different bands and to achieve high-stability fiber laser output. [0003] At present, research on wavelength-switchable erbium-doped fiber lasers at home and abroad has made great progress. The design uses cascaded fiber bragg grating (Fiber Bragg grating, FBG), polarization-maintaining f...

AI Technical Summary

Problems solved by technology

As a frequency-selective device, fiber Bragg gratings have been widely used in the design and manufacture of fiber lasers. At present, FBG is usually prepared in the optical fiber with the protective layer removed by ultraviolet exposure, and then the gate area is protected by recoating technology. However, the Bragg grating made by this method is used as a frequency-selective device, resulting in poor stability of the output laser wavelength.

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