基于MEMS反射镜的窄线宽外腔可调谐半导体激光器

Narrow Linewidth External Cavity Tunable Semiconductor Laser Based on MEMS Mirrors

基于大转角的电磁式MEMS反射镜和闪耀光栅作为外腔调谐元件,设计了Littman-Metcalf结构的外腔半导体可调谐激光器,MEMS反射镜可准确控制偏转角度,2 h内角度复位调谐波长漂移小于20 pm,该可调谐激光器实现了1435.81~1555.83 nm(120.02 nm)的稳定的波长调谐,全波段波长调谐过程中激光器边模抑制比大于30 dB,相同调谐电流下,激光器波长控制误差小于20 pm。注入电流350 mA时,外腔激光器输出功率达25.89 mW,最小阈值电流68 mA。利用延迟自外差法测得可调谐激光器的线宽优于69 kHz。该研究成果有望在激光雷达、相干激光通信、光学传感器及计量检测等诸多领域发挥重要作用。

A novel design of a Littman-Metcalf structure external-cavity semiconductor tunable laser was introduced,where a large-angle electromagnetic MEMS mirror and a blazed grating for external cavity tuning was utilized.The deflection angle was precisely controlled by the MEMS mirror,ensuring that the wavelength drift during angular reset tuning was kept below 20 pm over 2 hours.A stable wavelength tuning range from 1435.81 to 1555.83 nm(120.02 nm)was achieved,with a sidemode suppression ratio higher than 30 dB throughout the entire tuning range.The wavelength control error of the laser was maintained under 20 pm with consistent tuning currents.Under the bias current of 350 mA,the output power of 25.89 mW was achieved.The minimal threshold current of the proposed laser was 68 mA.By employing a delayed self-heterodyning method,the linewidth of the tunable laser was ascertained to be finer than 69 kHz.Significant potential for applications in LIDAR,coherent laser communication,optical sensors,and metrological measurements was held by these advancements.