Optical transmitter, optical transmission method, and transmission/reception system

摘要

An optical transmitter includes: a selection circuit; a signal processing circuit; an optical modulator; and a control circuit. The selection circuit selects signal components on the sides of the maximum and minimum values in a multivalued electrical signal for modulation of a transmitting signal. The signal processing circuit generates a multivalued electrical signal into which the transmitting signal is converted by a combination of a superimposed signal that a low-frequency wave is superimposed on the signal components and a signal having a plurality of intermediate amplitude values on which the low-frequency wave is not superimposed. The optical modulator modulates a carrier light on the basis of the multivalued electrical signal. The control circuit controls the reference amplitude value or amplitude of the multivalued electrical signal on the basis of the low-frequency components contained in a modulated optical signal.

主权项

1. An optical transmitter comprising:
a selection circuit that selects signal components on sides of maximum and minimum values in a multivalued electrical signal for modulation of a transmitting signal as a low-frequency superimposed part, the multivalued electrical signal having three or more values including the maximum and minimum values and an intermediate amplitude value; a signal processing circuit that generates a multivalued electrical signal from a combination of a superimposed signal obtained by superimposing a low-frequency wave on the low-frequency superimposed part and a signal having a plurality of intermediate amplitude values on which the low-frequency wave is not superimposed; an optical modulator that modulates a carrier light on the basis of the multivalued electrical signal generated by the signal processing circuit; and an amplitude control circuit that controls a reference amplitude value or amplitude of the multivalued electrical signal on the basis of low-frequency components contained in a modulated optical signal modulated by the optical modulator.