用注入锁模法改善DFB激光器的频率响应

验证了通过注入锁模方法,分布反馈(DFB)半导体激光器的频率响应可以得到明显的改善.实验中通过一个环形器,将主激光器的输出光注入到从激光器.测量了从激光器在有注入光和没有注入光时的光谱和频率响应.发现在不同的注入光强度和波长下,激光器的调制带宽和弛豫振荡峰频率会发生变化.通过适当选择注入光的强度和波长,频率响应可以得到改善.激光器频率响应的改善可以用两个模式的拍频来解释,一个模式是从激光器的主模,另一个是主激光器的模式,该模式与从激光器的边带重合.该理论与实验结果符合得很好.

Improvement of the Frequency Response of a DFB Laser Using Injection Locking

This paper reports that the frequency responses of a direct-modulated DFB laser diode can be improved using an injection locking method.In the experiments,the optical output power of the master laser is injected into the slave laser via a circulator.The optical spectra and frequency responses of the slave laser with and without injection are measured, respectively.The modulation bandwidth and the relaxation oscillation frequencies of the laser are quite different at different injection powers and wavelengths.The frequency responses can be improved by choosing the proper optical power and wavelength of injection.We believe that the improvement of the frequency response is due to a two-mode beat that includes the main mode of the slave laser and the master laser mode, which coincides with the side band of the slave laser.This theory is supported by the experiments.