Patent ID: 7362978

Claim:
A duobinary optical transmission apparatus having an optical modulator for generating a modulated optical signal made by a modulation of an optical carrier wave, said optical modulator comprising: a T flip-flop configured to receive a two-level data signal and generate a toggled output signal at every rising edge of the two-level data signal; an AND gate configured to perform an AND operation on the two-level data signal and the toggled output signal; a delay configured to delay an inverted signal of the two-level data signal by a predetermined time; an attenuator being directly coupled to the output of the delay and being configured to reduce intensity of the delayed output signal; a power combiner being directly coupled to the output of the AND gate and output of the attenuator and being configured to generate a three-level signal by adding an output signal of the AND gate and an output signal of the attenuator; a modulator driving signal generator for generating a modulator driving signal upon receiving the three-level signal; a light source for generating optical carrier wave; and an interferometer-type optical modulator for modulating the carrier wave into a two-level optical signal according to the modulator driving signal.