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

An optical transmission/reception method, comprising:

• imparting a polarization rotation to signal light by optical modulation with respect to data, correspondingly multiplying first polarization components and second polarization components of an input signal by first cos ωt and sin ωt and second cos ωt and sin ωt, and correspondingly adding a first set of different polarization components output from the complex multipliers and adding a second set of different polarization components output from the complex multipliers to output the data;
• performing the optical modulation based on the data;
• transmitting the signal light subjected to the optical modulation;
• converting the signal light received via a transmission path to a digital electric signal in an optical receiver;
• and
• performing digital signal processing which imparts a change to the digital electric signal having a property substantially inverse to a property of the data in an optical transmitter.

An optical transmission/reception system comprising:

• a modulator that modulates light based on data to output signal light;
• a transmission-side signal processing unit that includes complex multipliers and complex adders and that processes an input signal using the complex multipliers and the complex adders for polarization rotation, the modulator imparting a polarization rotation to the output signal light by optical modulation with respect to the data;
• an optical transmitter in which the modulator performs the optical modulation based on the data subjected to the transmission-side signal processing unit;
• and
• an optical receiver that includes a converter converting the signal light input from the optical transmitter via a transmission path to a digital electric signal for each polarization component, and a reception-side signal unit performing reception-side digital signal processing which imparts a change to the digital electric signal from the converter having a property substantially inverse to a property of the data in the transmission-side signal processing unit, wherein
• the transmission-side signal processing unit includes that the complex multipliers multiply first polarization components and second polarization components of the input signal by first cos ωt and sin ωt and second cos ωt and sin ωt, and the complex adders correspondingly add a first set of different polarization components output from the complex multipliers and add a second set of different polarization components output from the complex multipliers to output the data.