窄线宽低噪声可调谐非平面环形激光器

Narrow linewidth low noise tunable nonplanar ring lasers

针对空间相干光通信和探测等应用,对非平面环形激光器的线宽、噪声和调谐特性进行了系统的实验研究。单频输出功率达到752 mW,光光效率42%,斜率效率54%。采用延时自外差拍频法测试了激光线宽,其随泵浦功率的增加而增大,输出功率小于200 mW时,线宽小于1 kHz,在最高输出功率下线宽为2.3 kHz。激光强度噪声主要由弛豫振荡引起,相对强度噪声(RIN)随着泵浦功率的提高而降低。在1.78W泵浦功率下,RIN达到-93 dB/Hz。采用温度和压电两种方式进行了激光调谐。温度调谐范围达到62 GHz。压电调谐范围达到130 MHz,响应带宽100 kHz。

For applications in coherent optical communications in space and coherent laser detection, the linewidth, noise and tuning characteristics of nonplanar ring lasers were studied systematically in experiment. The output power in single frequency reached 752 mW, with 42% optical-optical efficiency and 54% slope efficiency. The laser linewidth was measured by delayed self-heterodyne interferometry technique. Linewidth decreased with increased pump power. The linewidth was smaller than 1 kHz with output power smaller than 200 mW, and the linewidth was 2.3 kHz at highest output power. Laser intensity noise was mainly attributed to relaxed oscillation. The relative intensity noise （RIN） decreased with increased pump power. The RIN was -93 dB/Hz at 1.78 W pump power. The laser frequency could be tuned by temperature and PZT. Thermal tuning range reached 62 GHz. PZT tuning range was 130 MHz with 100 kHz response bandwidth.