Optical direct modulation and external modulation
Direct modulation of semiconductor lasers is to modulate the laser by superimposing the pre-modulated (AM, FM, PCM) signal current on the bias current of the laser. Because it is to change the intensity of light, it is also called intensity modulation. For digital transmission, although the speed is very high, only two working states of optical signal or non-optical signal are ...
2019-01-20