摘要 |
A method for modulating an optical signal includes the following steps: modulating the intensity of the optical signal with a nonreturn-to-zero bit signal, and modulating the phase of the optical signal with a periodic phase-shift signal creating an alternating pi-phase shift every second, third or more consecutive bit. An optical transmitter for performing the above method comprises a first modulator (2) modulating the intensity of the optical signal with a nonreturn-to-zero bit signal, and a second modulator (3) modulating the phase of the optical signal with a periodic phase-shift signal creating an alternating pi-phase shift every second, third or more consecutive bit.
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