Fiber laser adopting end face coated cavity mirror

Abstract

The invention relates to a fiber laser adopting an end face coated cavity mirror. The fiber laser is characterized by comprising the coated cavity mirror, a pumping device and a doped fiber serving as a gain medium, wherein the coated cavity mirror is a fiber end face thin film with a certain optical characteristic which is formed by coating a film on the end face of a small section of fiber; andthe small section of fiber is a section of gain fiber or a section of undoped fiber which has the same parameter as the gain fiber. The end face coating film is adopted by the fiber laser as a cavitymirror, so that the service life and the damage threshold of the cavity mirror are improved; and consequently, the cavity mirror cannot be ablated or damaged when working at a higher power.

Description

technical field [0001] The invention relates to a fiber laser, in particular to a fiber laser using an end-face coated cavity mirror. Background technique [0002] Because of its excellent beam quality, very high power and power density, easy cooling, high stability and reliability, fiber lasers have attracted increasing attention and have been widely used in many fields. In fiber lasers, Fabry-Perot cavities are generally used as resonant cavities. The cavity mirror of the Fabry-Perot cavity has many different forms: placing a dichroic mirror before and after the fiber, coating the fiber end face, writing the fiber grating into the gain or non-gain fiber, etc. In the article "Spectral profile and multiplexing of Bragg gratings in photosensitive fiber" (OPTICS LETTERS, Vol.16, No.12, 1991), R.J.Campbell and R.Kashyap first proposed the method of using fiber gratings for fiber lasers. Since then, fiber gratings have been widely used in the design and manufacture of fiber la...

AI Technical Summary

Problems solved by technology

For the first method, if it is used for high-power fiber lasers, since the gain fibers are double-clad fibers, the outer cladding is generally made of polymer materials, which are easily damaged during the hydrogen-loaded sensitization process, which seriously affects the pumping light. Coupling, resulting in low coupling efficiency. At the same time, the polymer outer cladding material is generally opaque to ultraviolet light, which also brings difficulties to the production of fiber gratings.

For the second method, after splicing the grating-written non-gain fiber to the double-clad gain fiber, there will be splice loss

Moreover, in high-power lasers, the strong light beam will cause certain damage to the grating, which will change the refractive index of the grating and affect its performance; in severe cases, the grating will be ablated and make it invalid

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