Patent ID: 8208819

Claim:
An optical signal generator comprising: a splitter that splits an optical pulse train into a first pulse train and a second pulse train; a first modulator that receives the first pulse train and first data signal and generates a first modulation signal by performing on-off-keying or phase modulation on the first pulse train based on the strength of the first data signal; a second modulator that receives the second pulse train and second data signal and generates a second modulation signal by performing the on-off-keying or phase modulation on the second pulse train based on the strength of the second data signal; a signal-switching unit that delays pulses of the second modulation signal, or adjusts a phase of a carrier included in the second modulation signal according to a switching signal; and a multiplexer that generates an optical modulation signal by multiplexing the first modulation signal and the second modulation signal.