| 摘要 |
An injection laser 24 has drive circuitry which includes a generator 25 for superimposing a low frequency signal on the drive signal to the laser. The light output of the laser is sensed by a photodetector 33. A rectifier 36 rectifies the low frequency component of the photodetector output and the rectified signal is compared with a reference signal in a comparator 38. The output of the comparator 38 is fed to the drive circuitry to maintain the d.c. bias of the laser close to the laser threshold, thereby stabilising the output intensity of the laser. <IMAGE> |
