MODULATOR, OPTICAL TRANSMITTER AND MODULATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a modulator, an optical transmitter and a modulation method which reduce transient response of electric current flowing through a laser diode driver (LDD) which occurs if the LDD and a laser diode (LD) are connected with a differential IF of coupling capacitance, and obtain stable optical output.

SOLUTION: An optical transmitter 301 comprises an LD 8 and a modulator 101. The modulator 101 includes an LDD 7 for generating a modulation signal based on a control signal which controls transmitting and stopping a data signal and an optical output signal; a differential IF51 for modulating driving current of the LD 8 by capacitively coupling a cathode and an anode of the LD 8 using the modulation signal generated by the LDD 7 as a differential signal; and a cancellation circuit (5-1, 5-2) for generating cancellation current based on the control signal and for superimposing the cancellation current on the driving current modulated with the modulation signal from the differential IF51.

COPYRIGHT: (C)2012,JPO&INPIT