OPTICAL TRANSMITTER OF VIDEO BASE BAND

摘要

PURPOSE:To avoid the quality deterioration of the transmitted signal, by applying the compensated signal to the laser diode of a power source after inverting the polarity of the compensated signal. CONSTITUTION:The linearity is previously changed through a linearity compensating circuit 1 for a video signal (a) of the base band to be transmitted. Then a waveform (b) obtained by extending the white part of the signal (a) is turned into a waveform (c) having an inverted polarity to be applied to a laser diode 6. Thus the nonlinear part is compensated for the optical output characteristics of the diode 6, and at the same time the white part of the signal (a) has a low output level of the beam. Accordingly the diode 6 has a multi-mode to reduce the occurrence of the speckle noise, and the distortion of a waveform is reduced.