BURST OPTICAL RECEPTION CIRCUIT

PURPOSE: To provide a burst optical reception circuit which has a high-speed and wide dynamic range. CONSTITUTION: The optical signal received by a photodetector 1 undergoes the current/voltage conversion and amplification through a preamplifier 2 and is inputted to a differential amplifier 4 via a resistance 3a. The negative phase output of the amplifier 4 is fed back to one of both input terminals of the amplifier 4 via a nonlinear resistance 5a, and the gain of the amplifier 4 is decided based on the ratio set between both resistances 3a and 5a. The positive and negative phase outputs of the amplifier 4 are inputted to the peak detection circuits 6a and 6b respectively to detect and hold the peak value of burst signals. A differential amplifier 7 calculates the difference of peak value between both burst signals, and this difference is smoothed by an LPF 8 and supplied to the other input terminal of the amplifier 4 via a resistance 3b. At the same time, the output of the circuit 6a is supplied to the other input terminal of the amplifier 4 via a nonlinear resistance 5b. In such a constitution, the number of parts can be decreased and no adjustment is needed for these parts so that the economical properties can be improved.