Research of narrow line-width Er3+-doped fiber ring laser with FBG F-P etalon and FBG Sagnac loop

Abstract

A novel method of narrow line-width Er 3+ -doped fiber ring laser based on FBG F-P etalon and FBG Sagnac loop is presented in this paper. The all-fiber single frequency and narrow line-width Er 3+ -doped fiber ring laser has been designed in which two 976 nm laser diodes are used as the pump sources, the high concentration Er 3+ -doped fiber as the gain medium, the fiber Faraday rotator is adopted to eliminate the spatial hole burning effect, the FBG F-P etalon and FBG Sagnac loop filter can discriminate and select laser longitudinal modes efficiently. The experiment system using 3m long Er 3+ -doped fibers is presented, when the maximum pump power of two 976nm laser diodes is 146mW, the fiber laser exhibits 16mW threshold and stable single frequency 1550nm laser with the output powers of 45mW is acquired, and the slope efficiency is about 34.6%. The 3dB line-width is less than 9.3 kHz, measured by the delayed selfheterodyne method with 15km single-mode fiber, and no mode hopping is observed. The fiber laser has the advantages of simple structure, high efficiency and high reliability and it has great potential applications in the fields of optical fiber sensing system.