Abstract
This thesis reports the studying of the optical phase locked loop. The system is successful in phase locking two external cavity lasers: in phase-locked states, the bandwidth of the lasers’ beat signal is about 40 Hz, the capture range is about 5MHz, the lock range is about 700MHz and the offset frequency between the two lasers can be 100, 200 and 300MHz; moreover, by using the integrator, the phase-locked states can be kept in 4 hours. There are some advantages of my experiment. First of all is that I have two methods to phase lock two external cavity lasers. The modulation function of a laser current source is not an important point when the system needs a laser current source. Both a modulation function of a laser current source and electronic circuits that homemade can work for phase locking. Moreover, the apparatus in the system are easy to get.