| 摘要 |
A technique of detecting a peak value for each output light pulse from a light amplifier by using a light amplifying fiber is provided. A peak value detector 16 detects power of an output light pulse which is output from the light amplifying fiber. A light receiving element 15 receives a group of light pulses including a plurality of pulses and converts the group of light pulses into a current signal. A current/voltage converter circuit 31 converts the current output from the light receiving element to voltage. An integration circuit 32 integrates the voltage output from the current/voltage converter circuit 31. A PGA (Programmable Gain Amplifier) 33 amplifies the signal output from the integration circuit 32 and provides the signal for the AD converter circuit 34. The gain of the PGA 33 is set by a gain setting signal from the signal processing circuit 40. The signal processing circuit 40 adjusts the gain of the PGA 33 so that the gain increases as the repetition frequency of the group of pulses increases. |
