半导体激光器的强度和相位起伏一直是影响其应用的关键所在.在实验上研究了自由运转模式下半导体激光器的强度噪声.采用自制的分辨率为0.01um的光谱仪成功地分辨出数十个边模,并利用射频低噪声光电探测器系统,分析了激光器的主模与边模之间以及各边模之间的强度噪声关联特性.从实验上证实了主模与边模之间的负关联效应,同时观察到边模之间存在的周期性负关联.该结果对进一步认识半导体激光器噪声的产生机制及强度压缩光的产生机制具有重要意义.
Intensity fluctuation and phase noise are key factors limiting the applications of the diode lasers is many fields. The intensity noise of a free-running diode laser was investigated experimentally. Tens of longitudinal modes from the diode laser were successfully separated and identified by a self-made monochromator with 0.01 nm resolution. The noise of either the individual mode or the jointed modes of main mode and the sideband modes was detected using a low-noise radio frequency photodetector. The properties of the intensity noise between either the main mode and the side modes, or the side modes themselves were investigated systematically. The anticorrelation between main mode and side modes was confirmed, and the periodical anticorrelations between small longitudinal modes were found. These results can help us to understand the mechanism of the intensity noise of the diode lasers as well as the noise suppression for intensity-squeezed light generation.