光注入条件下分布反馈半导体激光器的放大特性研究及其在微波信号产生中的应用

Amplification Properties of a Distribution Feedback Semiconductor Laser under Optical Injection and Its Application in Generating Microwave Signals

选用不带内部隔离器的普通商用分布反馈式(DFB)半导体激光器作为从激光器,用一个经马赫-曾德尔外调制器进行奇数阶边带抑制调制的光信号作为探测信号,通过测量不同失谐频率条件下从激光器输出光信号经光电探测器检测所得的射频信号的功率,对光注入条件下DFB激光器的放大特性进行了研究,得到了不同注入功率比条件下DFB激光器的放大特性曲线。同时研究了-2级边带得到最大放大时的最佳失谐频率以及不同注入功率比条件下探测光信号的载波和-2级边带分别得到的增益。利用DFB激光器对探测光-2级边带的放大作用,得到了高边带抑制比的单边带信号,产生了二倍频本地振荡信号的微波信号。这为用光学方式产生高频微波信号提供了一种新的方法。

An standard commercialized fiber-pigtailed distribution feedback （DFB） semiconductor laser without internal isolator is chosen as the slave laser to study the amplification properties of a semiconductor laser under optical injection. A signal consisting of a carrier and two second order sidebands is used as a probe signal, which is generated by a Mach-Zehneder modulator （MZM） biased at the maximum transmission point. The amplification properties of the slave DFB laser under different injection powers are measured by measuring the power of the resonantly amplified probe signal after photodetector. Relationship between the optimum detuning frequency at largest gain of -2nd order sideband and the gain of the carrier and the -2nd order sideband in different injection ratios is also investigated. Optical single sideband （SSB） signal with high sideband suppression （SSR） is achieved, and a microwave signal with doubled frequency of the local oscillator （LO） signal with a good signal to noise ratio （SNR） is generated after photodetector. It provides a new way to generate a high frequency microwave signal.