Single frequency fiber ring laser with mode selection by FBG F-P etalon
The principle of single frequency operation of the fiber laser with mode selected with fiber Bragg grating Fabry-Perot etalon is presented.The all-fiber single frequency Er~(3+)-doped fiber ring laser has been designed in which two 976 nm laser dodes are used as the pump sources,the high concentration Er~(3+)-doped fiber as the gain medium,the travelling cavity is adopted to eliminate the spatial hole burning effect.The designed etalon can discriminate and select laser longitudinal modes efficiently and a stable single-frequency laser is obtained.The experiment using 5 m and 3 m long Er~(3+)-doped fibers respectively is presented.When the maximum pump power is 145 mW,the output powers are 19 mW and 42 mW respectively and the optical-optical conversion efficiency are 13% and 29%,the slope efficiency are 16% and 33%,the 3 dB bandwidths of the laser are 0.01 nm,and no mode hoppings are observed.The fiber laser has the advantages of simple structure,high efficiency and high reliability and it can be used to build single-frequency,high-efficiency and high-power fiber laser.