Patent ID: 7379671

Claim:
An optical transmitter, comprising an optical modulation processing unit that includes: a signal carrier-suppressed pulse modulating unit that performs signal carrier-suppressed pulse modulation on a light source signal to thereby create a carrier-suppressed-return-to-zero signal; a phase modulating unit that performs phase modulation on a data signal based on the carrier-suppressed-return-to-zero signal to thereby convert the data signal into a phase-modulated signal; and an optical filtering unit that filters out redundant frequency components included in the phase-modulated signal, wherein the signal carrier-suppressed pulse modulating unit performs the signal carrier-suppressed pulse modulation based on a clock signal with a frequency, wherein the frequency of the clock signal is half of a signal frequency of the data signal, and creates the carrier-suppressed-return-to-zero signal such that peaks of an optical frequency spectrum are separated from each other by the signal frequency; and the optical filtering unit filters out all frequency components that fall outside a frequency band determined by the signal frequency.