C+L band erbium-doped fiber laser based on femtosecond laser direct writing FBGs

Abstract

The invention discloses a C+L band erbium-doped fiber laser based on femtosecond laser direct writing FBGs. The C+L band erbium-doped fiber comprises a sensing fiber, wherein a wavelength division multiplexer is arranged on the sensing fiber and is successively connected in series with a C-band erbium-doped fiber, an L-band erbium-doped fiber, a polarization controller, an FBG array, and a broadband reflector. The FBG array comprises three cascaded FBGs and is produced by a femtosecond laser direct writing method. The three FBGs have the same length and different reflection wavelengths. In theC+L band erbium-doped fiber laser, a femtosecond laser passes through a fiber protective layer to directly write FBGs having periods of 538 nm, 542 nm and 547 nm respectively and connected end to endin a single-mode fiber with a coating unremoved as a frequency selection device, and constitutes a linear cavity fiber laser in combination with the C-band and L-band erbium-doped fibers, a pumping source, the polarization controller and the broadband total reflector, realizes wavelength-switchable single-wavelength and dual-wavelength laser output, and suppresses side modes in the laser spectrum, and improves wavelength stability.

Description

technical field [0001] The invention relates to the field of optical fiber sensing, in particular to a C+L band erbium-doped fiber laser based on femtosecond laser direct writing FBG. 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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