Erbium-doped fiber laser for preparing core-clad composite FBG based on femtosecond laser direct writing

Abstract

The invention designs an erbium-doped fiber laser for preparing a core-clad composite FBG based on femtosecond laser direct writing, and realizes wavelength-switchable single-wavelength and dual-wavelength laser output. Composite fiber bragg grating inscribing with the period being 541 nm is achieved in a polyimide coating layer optical fiber through a method that femtosecond laser penetrates through an optical fiber protection layer to be directly written on a fiber core and a cladding, and the reflection wavelengths of grating arrays with the grating area length being 3000 microns serving as a frequency selecting device are 1562.85 nm and 1564.52 nm respectively; an erbium-doped optical fiber combination with the specific length is selected as a laser gain medium, a pumping source, a polarization controller and a broadband total reflective mirror are combined to form a linear cavity optical fiber laser, and wavelength-switchable laser output can be achieved.

Description

technical field [0001] The invention relates to the field of optical fiber devices, in particular to a femtosecond laser direct writing core cladding composite FBG erbium-doped fiber laser. 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-maintaini...

AI Technical Summary

Problems solved by technology

In summary, multi-wavelength tunable fiber laser output can be realized by adopting the above technologies, but the system usually uses special optical fiber, or connects an external modulation structure in the cavity, which increases the complexity of the system; in addition, the frequency selection device The performance of the laser is closely related to the spectral characteristics of the output laser

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