Abstract:We theoretically propose the structure of all-solid photonic band gap fiber to support LP01 mode at 980 nm and four modes of LP01, LP11, LP02 and LP21 at C bands. We research characteristics of the photonic band gab and apply photonic fiber as gain medium to fiber lasers, finally realizing separate amplification of LP11 and LP21 high-order modes with single-mode stable pump light of LP01 mode at 980 nm. Besides, we realize LP11 mode and LP21 mode laser output of dual-wavelength.