| 摘要 |
PURPOSE: To obtain the wavelength multiplex optical transmission system with high transmission quality by adjusting a gain with a pre-stage optical amplifier provided to an input side of an optical receiver. CONSTITUTION: A wavelength multiplex optical signal comprising the synthesized signal of two signal lights whose wavelengths are different as λa, λb by a synthesizer D1 is sent through an optical fiber transmission line F to which optical amplifiers A1-An are provided. Pre-stage optical amplifiers Ba, Bb and receivers RXa, RXb are cascade-connected via an optical demultiplexer D2 at the end of the optical fiber transmission line F. The optical demultiplexer D2 demultiplexes the wavelength multiplex signal by a demultiplex ratio of 1:1 and each demultiplexed signal is distributed by filters with prescribed pass bands, then the signal light whose wavelength is λa is given to the pre-stage optical amplifier Ba and the signal light whose wavelength is λb is given to the pre-stage optical amplifier Bb. Then the gain of the pre-stage optical amplifiers Ba, Bb is individually adjusted to provide a signal light with an optimum optical level to the receivers RXa, RXb. |
