| 摘要 |
PURPOSE:To reduce the effect of the nonlinear distortion the light source features by combining the optical modulation signals given from plural units of the optical transmitter and then transmitting the combined signals via one piece of the transmission optical fiber. CONSTITUTION:Optical transmitters 1 - 4 consist of analog signal sources 5 - 8 featuring the central frequencies f1 - f4 plus light emitting diodes 9 - 12 which are modulated by sources 5 - 8. The optical modulation signals 13 - 16 given from transmitters 1 - 4 are combined to transmission optical fiber 22 by photo coupler 21 and via optical fibers 7 - 20. The signals are then converted to the electric signals via photo detector 23 and at the other end of optical fiber 22 and then divided into central frequencies f1 - f4 through band pass filters 25 - 28 after amplification to be received at analog signal receiving parts 29 - 32. In this constitution, if the maximum degree of modulation of the light emitting diode caused by the nonlinear distortion or the like is, for instance, 80%, the ratio of that 80% can be left as it is with no relation to the number of multiplication. |
