Transimpedance amplifier for receiving burst optical signal

A transimpedance amplifier configured to convert an input current generated by a photodetector in accordance with a burst optical signal to a differential signal including a positive-phase component and a negative-phase component and output the differential signal, the transimpedance amplifier comprising:

• an input terminal configured to receive the input current;
• a single-ended amplifier circuit having an input node that is electrically connected to the input terminal, the single-ended amplifier circuit being configured to convert a current signal input to the input node to a voltage signal;
• a first feedback circuit having a time constant, the first feedback circuit being configured to generate a bypass current at a response speed adjusted by the time constant;
• a differential amplifier circuit configured to generate the differential signal in accordance with a difference between the voltage signal and a reference voltage signal;
• and
• a first detector circuit configured to detect an end of the burst optical signal based on the differential signal,
• wherein the first feedback circuit includes a capacitor, generates the bypass current in accordance with a charging voltage of the capacitor based on the difference between the voltage signal and the reference voltage signal, and subtracts the bypass current from the input current,
• wherein the first feedback circuit detects a start of the burst optical signal based on the charging voltage, maintains the time constant at a first time constant for a predetermined period from the detection of the start of the burst optical signal, and, upon an elapse of the predetermined period, switches the time constant from the first time constant to a second time constant that is larger than the first time constant, and
• wherein the first detector circuit resets the charging voltage of the capacitor by releasing electric charge stored in the capacitor in response to the detection of the end of the burst optical signal.