A chirped RZ-AMI optical transmitter includes a first logic gate for receiving a first signal obtained by pre-coding binary data and a second signal having a waveform obtained by inverting and delaying the first signal, and outputting a third signal obtained by logically operating on the first and second signals. A second logic gate receives a fourth signal having a waveform obtained by inverting the first signal, and a fifth signal having a waveform obtained by delaying the first signal. The second logic gate outputs a sixth signal obtained by logically operating on the fourth and fifth signals. A Mach-Zehnder Modulator (MZM) modulates an input light according to the third and sixth signals and outputs an RZ-AMI optical signal.