Stable Narrow Linewidth Ring Fiber Laser with a Passive Fiber BraggGrating Fabry-Perot Etalon and a Fiber Saturable Absorber

摘要

Narrow linewidth fiber lasers have become more and more necessary in field of coherent communication, fiber opticsensor, and high resolutions optical spectrum analysis, especially long-range distributed fiber sensing system. In thispaper, a simple and stable narrow linewidth Er~(3+)-doped ring fiber laser is first proposed and experimentallydemonstrated. In the cavity, a passive fiber Bragg grating Fabry-Perot (FBG F-P) etalon acts as mode-selecting device togreatly reduce the longitudinal-mode density, while a section un-pumped Er~(3+)-doped fiber serves as a saturable absorberto ensure the single longitudinal-mode (SLM) operation. Meanwhile the stability of lasing frequency is further improvedby controlling the temperature of the FBG F-P, and then through varying the temperature the lasing wavelength tuning isachieved also. Finally stable SLM laser at 1550nm with linewidth about 7.5 kHz, maximum output power 39 mW andthe corresponding slope efficiency 30% is acquired.