| 摘要 |
PROBLEM TO BE SOLVED: To compensate the non-linearity of the light output of a light modulator with respect to a drive signal, and to suppress the excessive light emission of the light modulator when an RF signal is put into an off-state.SOLUTION: A drive circuit 20 includes: a signal detection circuit 40 for detecting the presence/absence of an RF signal; a buffer circuit 70 for inputting the RF signal, and for outputting an output signal Dout and an output signal DoutB; and a cross point control circuit 50 for supplying an offset voltage to the buffer circuit 70, and for controlling the cross point of the output signal Dout and the output signal DoutB. The buffer circuit 70 outputs the output signal Dout as the drive signal of a light modulation element 21, and the cross point control circuit 50 switches the voltage value of the offset voltage in accordance with the presence/absence of the RF signal detected by the signal detection circuit 40. |
