采用可调Mach-Zehnder滤波的波长可切换掺铒光纤激光器

为了实现高稳定性的可调谐激光输出，提出并设计了一种基于马赫-曾德（M-Z）结构和光纤光栅串结合的掺铒光纤激光器，在M-Z干涉结构的一个干涉臂中加入光学延迟线（ODL），实现对干涉间隔的灵活可调。系统结构设计采用976 nm波长的LD作为泵浦源，长度为6 m的掺铒光纤作为增益介质；采用光栅串将特定波长的光反射回环形腔形成振荡；采用M-Z结构产生梳状滤波用来对光栅串反射回的光进行选择；通过调节ODL来改变腔内损耗，进而实现激光的可调谐输出，并通过在系统中加入可饱和吸收体（SA）和子腔结构来抑制波长的跳变。实验中，在泵浦功率为100 mW时，实现了单波长双波长和三波长的稳定的激光输出。单波长共输出13个，调谐范围为1 570~1 596 nm，调谐间隔为2 nm，边模抑制比均大于50 dB。

Switchable erbium-doped fiber laser utilizing tunable Mach-Zehnder filter

In order to realize a highly stable and tunable laser output, an Er3+-doped fiber laser based on Mach-Zehnder filter structure and grating array made by femtosecond laser was proposed, and an optical delay line(ODL) was set into one interference arm to tune the interference interval flexibly. In the designed configuration, one 976 nm laser diode (LD) was used for pumping; an Er3+-doped fiber (EDF) of 6 m length was selected as the gain medium; The grating array will selete the femtosecond light reflection loop cavity specific wavelength oscillation form; the M-Z structure, which was used as comb filter, was adopted to select the wavelength reflected by the grating array; Tuning laser output can be realized by adjusting the ODL. In the experiment, when the pump power was 100 mW, a stable and tunable single, dual and triple wavelength output laser was observed. The single wavelength tunable interval was 2 nm within 1 570-1 596 nm, and the side-mode suppression ratios (SMSRs) of all were more than 50 dB.