Optical transmitter and optical transmitter control method using variable duty ratio setting and alternate phase inversion for optical clock pulses

Abstract

An optical transmitter for realizing a high tolerance with respect to the group velocity dispersion of the optical fibers, a small receiver sensitivity degradation, and an improved stability that is hardly affected by the group velocity dispersion even in the case of network scale expansion, is constructed by a light source section for generating optical clock pulses synchronized with a signal bit rate while maintaining a duty ratio of the optical clock pulses constant, which is capable of variably setting the duty ratio, and an encoding section for encoding the optical clock pulses by using electric signals synchronized with the optical clock pulses while setting a relative optical phase difference between the optical clock pulses in adjacent time-slots to be an odd integer multiple of &pgr;.