D-shaped fiber-based cross-polarization beat laser and sensor

Abstract

The invention provides a D-shaped fiber-based cross-polarization beat laser and a sensor. The laser comprises a pump laser, a wavelength division multiplexer connected with the pump laser, a first fiber Bragg grating, one end of which is connected with the wavelength division multiplexer, a second fiber Bragg grating, one end of which is connected with an output fiber, and an erbium-doped D-shaped fiber which is encapsulated between the other end of the first fiber Bragg grating and the other end of the second fiber Bragg grating, wherein the first fiber Bragg grating, the second fiber Bragg grating and the erbium-doped D-shaped fiber are integrated on one fiber. The distributed fiber grating is adopted as a reflector to form an ultrashort resonant cavity, and the cavity length can be effectively shortened, so that the laser can run in a single-longitudinal-mode state, and the generated laser has good coherence. The D-shaped fiber is used as the body of the resonant cavity, the constraining performance of the resonant cavity on light can be reduced, and part of the transmitted light is leaked from one side to form an evanescent field which is sensitive to external environment changes, so that induction of a specific parameter can be realized.

Description

technical field

[0001] The invention relates to the field of laser technology, in particular to an orthogonally polarized beat-frequency laser and a sensor based on a D-type optical fiber. Background technique

[0002] Fiber laser (Fiber Laser) refers to a laser that uses a rare earth-doped glass fiber as a gain medium. Fiber lasers can be developed on the basis of fiber amplifiers: under the action of pump light, high power density is easily formed in the fiber, resulting in laser The laser energy level of the working substance is "particle number inversion", and when properly added to the positive feedback loop (to form a resonant cavity), the laser oscillation output can be formed.

[0003] As a laser light source with broad application prospects, fiber laser has the advantages of broadband tunability, high signal-to-noise ratio, and narrow output laser linewidth. It can be widely used in optical fiber sensing, optical fiber communication, optical processing, etc. field....

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