Patent ID: 8129671

Claim:
An optical receiver and amplifier comprising: a photodiode configured to generate a photocurrent in response to a light input; an output section configured to output an output voltage being a low level or a high level in response to a magnitude of the photocurrent by using a power supply voltage supplied from a power supply; an output control circuit configured to control an input voltage of the output section such that the output voltage is set to the low level when the power supply is turned on or off during a period where the power supply voltage is lower than a predetermined value; a preamplifier section configured to generate a photovoltage by converting the photocurrent into a voltage by using the power supply voltage, wherein: the output control circuit is configured to output the input voltage of the output section for controlling the output voltage based on the photovoltage, the output section is configured to have a transistor arranged to be an NPN emitter follower or a source follower, and the output control circuit comprises: a first grounded emitter amplifier circuit whose base input is the photovoltage generated by the preamplifier section; and a second grounded emitter amplifier circuit whose base input is a divided voltage generated by dividing the power supply voltage, wherein an output of the first grounded emitter amplifier circuit is inputted to the output section as the input voltage, and an output of the second grounded emitter amplifier circuit is inputted to a transistor connected in parallel with a transistor of the first grounded emitter amplifier circuit.