以环行器和光纤光栅为腔镜的可调谐窄线宽激光器

Experiment Study on a Tunable Fiber Laser Using Optical Circulator and Tunable Fiber Bragg Gratings

实验报道了一种结构简单有效的波长可调谐掺饵光纤激光器。该激光器为线型腔结构,由环行器(DC)、掺铒光纤(EDF)、光纤布拉格光栅(FBG)和波分复用(WDM)组成。利用环行器作为全反射腔镜,光纤布拉格光栅作为波长选择性腔镜,通过对光纤光栅施加轴向应力改变其布拉格波长来实现光纤激光器的波长可调谐输出。利用此结构,室温下实验获得了中心波长在1543.5～1549.5 nm连续可调,边模抑制比(SMSR)大于50 dB的连续激光输出,激光输出线宽保持在0.01 nm以下。

A simple and effective tunable fiber laser is presented. The linear-cavity laser consists of a three-port optical circulator （OC）, a tunable fiber Bragg grating （TFBG）, a segment of high-concentration erbium doped fiber （EDF）, and a wavelength division multiplexing （WDM） coupler. By using an OC as the total-reflection mirror and a strain-induced uniform FBG as a partial-reflection mirror and a wavelength selector, a tunable wavelength is obtained. With single TFBG, a single wavelength lasing with a maximum wavelength tuning range of 6.00 nm, from 1543.50 to 1549.50 nm, is achieved experimentally. Within this tuning range, the full-width at half maximum （FWHM） of the laser output is smaller than 0.01 nm and the side mode suppression ratio （SMSR） is better than 50 dB.