Direct generation of 5 W all-fiber red laser at 635 nm

Abstract

We propose and experimentally demonstrate a compact high-power all-fiber Pr3+-doped red laser at 635 nm using highly-resistant dielectric-coated fiber mirror. The fiber laser consists of a 443 nm pump laser diode (LD), a double-clad Pr3+-doped fluoride fiber and a 443/635 nm dichroic fiber mirror. The 635 nm laser is directly generated by down-conversion gain of the Pr3+-doped fiber pumped by the 443 nm LD. The homemade dichroic fiber mirror is specifically designed for anti-reflection at 443 nm pump wavelength and high-reflection at 635 nm laser wavelength, and shows a high damaged density of >15 MW/cm2, which is very favorable to high-power visible laser operation. The red all-fiber laser directly generates a highest average power of ∼5 W at 635 nm which is more than twofold higher than previously reported, and the slope efficiency is as high as 25.7%. Different from the traditional visible laser by frequency doubling, this work offers a promising way for miniaturized, high-power fiber lasers in visible wavelength region.