QUADRATURE AMPLITUDE MODULATION SIGNAL GENERATING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a quadrature amplitude modulation signal generating device for obtaining a QAM signal without handling a multilevel electric signal.

SOLUTION: The present invention is basically characterized in that a quadrature amplitude modulation (QAM) signal is obtained without handling a multilevel electric signal by using a plurality of parallel MZMs such as four parallel MZMs (QPMZMs). This device is specifically characterized by comprising a first waveguide path (2), a first quadri-phase shift keying (QPSK) modulator (3) provided on the first waveguide path (2), a second waveguide path (5) having a point (4) which is multiplexed with the first waveguide path (2), and a second QPSK demodulator (6) provided on the second waveguide path (5).

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