Improvement of the Frequency Response of a DFB Laser Using Injection Locking
用注入锁模法改善DFB激光器的频率响应

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.