| 摘要 |
PROBLEM TO BE SOLVED: To improve the transmission quality of optical signals by improving the S/N of an optical receiver. SOLUTION: This optical receiver having an optical amplifier 1 is provided with an optical filter 4 using an over saturation absorber. As the over saturation absorber, any material to be operated to input light up to a prescribed light intensity level (threshold value) and to be operated as a transparent body for transmitting light higher than the light intensity level is used. In this case, the prescribed light intensity level (threshold value) is set to be a natural discharge light level corresponding to the 'Lo' level of an optical modulated signal after optical modulation due to the optical amplifier 1. |
