| 摘要 |
<P>PROBLEM TO BE SOLVED: To enlarge the dynamic range of an input light level monitor by a simple circuit configuration in an optical receiver having a variable optical attenuator and a photodetecting element. <P>SOLUTION: The optical receiver includes the variable optical attenuator 7 which attenuates input light based on an attenuation amount control value, a photodetecting element 8 which photodetects the output light of the variable optical attenuator 7, a current/voltage converter circuit 9 as a monitor means for monitoring the input light level to the photodetecting element, a variable optical attenuator control circuit 10 which obtains the attenuation amount control value according to the monitor output to output the attenuation amount control value to the variable optical attenuator 7, an attenuation amount calculating circuit 11 for converting the attenuation amount control value inputted from the variable optical attenuator control circuit 10 into a corresponding attenuation amount, and an adder circuit 12 which adds the converted attenuation amount and the monitor output to output the added result as an input light level monitor signal to the optical receiver. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
