Elliptical cladding polarization-maintaining large-mode-area gain fiber

The invention discloses an elliptical cladding polarization-maintaining large-mode-area gain fiber, which, in the structure, comprises a fiber core of the elliptical cladding polarization-maintaining large-mode-area gain fiber, an inner cladding layer, an elliptical stress layer, a first outer cladding layer, a second cladding layer and a third cladding layer, wherein the inner cladding layer coats the fiber core; the elliptical stress layer coats the inner cladding layer, and the elliptical stress layer is elliptical on the cross section of the elliptical cladding polarization-maintaining large-mode-area gain fiber; the first cladding layer coats the elliptical stress layer; the second cladding layer coats the first cladding layer; and the third cladding layer coats the second cladding layer. As birefringence of the elliptical cladding polarization-maintaining fiber is directly proportional to ellipticity, deposition of a polarization-maintaining stress region only needs to be additionally added during a rod forming process, steps such as drilling are not needed, unavoidable impurities can be prevented from being introduced in a fiber pre-form rod, loss of the fiber after wire drawing can be reduced, strength of the fiber is improved, the entire forming process has simple steps, and the birefringence and pump absorption of the fiber can be improved.