| 摘要 |
PURPOSE:To extend the dynamic range of the optical receiver by suppressing deterioration in the optical receiver such as distortion of the output of the receiver when the power of a received light is high. CONSTITUTION:A step attenuator 14 is inserted to a pre-stage of a first-stage amplifier 15 and a variable attenuator 16 is inserted to a post-stage. The input level of the first-stage amplifier 15 is attenuated by decreasing the attenuation of the step attenuator 14 when the power of the received light is small and by increasing the attenuation of the step attenuator 14 when the power of the received light is high thereby suppressing the distortion produced in the first- stage amplifier 15. |
