| 摘要 |
PROBLEM TO BE SOLVED: To sufficiently suppress the degradation of a signal wave system caused by a self-phase modulation/group velocity dispersion effect by applying strength modulation to signal light inputted from a light source and applying polarization modulation to the signal light so as to make the polarization states of temporally adjacent bits to be orthogonal with each other. SOLUTION: A strength modulator 2 outputs the signal light emitted from a light source 1 after modulating the strength corresponding to non-return to zero(NRZ) data 101 of transmission data. A polarization modulator 4 outputs the signal light outputted from the strength modulator 2 after applying the polarization modulator corresponding to an alternating signal 102. The alternating signal 102 is a signal with the same cycle as the NRZ data 101 and has the form '101010...', in which the adjacent bits are all different, and the temporally adjacent bits are mutually orthogonal as to the polarization. Therefore, the polarization modulated signal light even when it is degraded by the group velocity dispersion effect caused by passing through an optical fiber, the influence caused by the interference with a temporally adjacent bit will be reduced. |
