Light transfer apparatus and light transfer method

Abstract

This invention provides a light transfer apparatus and a light transfer method wherein a pair of phase conjugation signals can be transferred without degradation of frequency utilization efficiency and combined on a reception side with the transfer quality degradation being suppressed. The light transfer apparatus connects the light transmission unit (100) and the light reception unit (300) through the light transfer unit (200). The light transmission unit (100) comprises: a signal arrangement unit (102) that generates, on the basis of externally input plural-system signals, a pair of plural-system phase conjugation signals and mixture-dispersion-arranges the pair of phase conjugation signals in an orthogonal polarization electric-field; and a light modulation unit (104) that converts the electric signals supplied from the signal arrangement unit (102) into a light signal and outputs the light signal to the light transfer unit (200). The light reception unit (300) comprises: a photoelectric conversion unit (301) that converts the light signal transferred by the light transfer unit (200) into the electric signals; and a signal reconstruction unit (303) that combines the mixture-dispersion-arranged signals supplied from the photoelectric conversion unit (301), thereby reconstructing the original plural-system signals.

Description

technical field [0001] The present invention relates to an optical transmission device and an optical transmission method using a digital coherent method. Background technique [0002] In order to enable long-distance and large-capacity optical transmission, the subject is to overcome the limit of the optical signal-to-noise power ratio, realize high-density wavelength multiplexing, and overcome the nonlinear optical effect of optical fibers. [0003] First, on-off keying (OOK: On-Off Keying) is currently used as a technique for overcoming the limit of the optical signal-to-noise power ratio. However, in recent years, binary phase shift modulation (BPSK: Binary Phase-Shift Keying) or quaternary PSK (QPSK: Quaternary Phase-Shift Keying) has been adopted. [0004] Next, as a technique for realizing high-density wavelength multiplexing, a method of doubling the number of transmission bits per symbol by employing a polarization multiplexing method (Polarization Multiplexing) is...

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Problems solved by technology

[0009] However, in the method for compensating the nonlinear optical effect described above, there are problems in that the scale of the circuit for realizing digital signal processing is large, or a device for inverting the phase of light at the center of the transmission path is required.

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