Amplification circuit and optical communication apparatus provided with the amplification circuit
AssigneeFujitsu Limited
InventorKazunori Nishizono
Life of this patent
Estimating the term…
Abstract
An amplification circuit used in an optical communication apparatus includes a first amplifier for generating a first voltage signal corresponding to an input current, a second amplifier for amplifying the first voltage signal and generating a second voltage signal, a gain control circuit for generating a gain control signal for adjusting the gain of the first amplifier based on the second voltage signal, and a bias control circuit for generating a bias control signal for adjusting the bias current at the output of the first amplifier based on the gain control signal. The bias control signal stabilizes the bias voltage of the first amplifier during gain adjustment of the first amplifier.
Claims26
An amplification circuit for receiving an input current, the amplification circuit comprising:
- a first amplifier including a current-to-voltage conversion resistor for generating a first voltage signal corresponding to the input current;
- a second amplifier connected to the first amplifier for amplifying the first voltage signal and generating a second voltage signal;
- a first gain control circuit connected to the first and second amplifiers for generating a first gain control signal based on the second voltage signal and adjusting the resistance value of the current-to-voltage conversion resistor in accordance with the first gain control signal;
- and
- a bias control circuit connected to the first amplifier and the first gain control circuit for generating a bias control signal based on the gain control signal and adjusting the bias current at the output of the first amplifier in accordance with the bias control signal.
An optical communication apparatus for receiving signal light, the optical communication apparatus comprising:
- a first photoreceptor element for receiving the signal light and generating a first reception current;
- a first amplifier connected to the first photoreceptor element, including a current-to-voltage conversion resistor, wherein the first amplifier generates a first voltage signal corresponding to the first reception current;
- a second amplifier connected to the first amplifier for amplifying the first voltage signal and generating a second voltage signal;
- a first gain control circuit connected to the first and second amplifiers for generating a first gain control signal based on the second voltage signal and adjusting the resistance value of the current-to-voltage conversion resistor in accordance with the first gain control signal;
- and
- a bias control circuit connected to the first amplifier and the first gain control circuit for generating a bias control signal based on the gain control signal and adjusting the bias current at the output of the first amplifier in accordance with the bias control signal.
An optical communication apparatus comprising:
- a transmission circuit for generating a transmission current in accordance with a transmission signal;
- a light-emitting element for generating transmission signal light in accordance with the transmission current and generating a signal light detection signal;
- a photoreceptor element for receiving a signal light and generating a reception current;
- a reception circuit connected to the photoreceptor element for generating a reception signal corresponding to the reception current;
- and
- a switching circuit connected to the light-emitting element, the transmission circuit and the reception circuit, for connecting the light-emitting element and the transmission circuit in a transmission mode and connecting the light-emitting element and the reception circuit in a reception mode, the reception circuit including:
- a first amplifier including a current-to-voltage conversion resistor for generating a first voltage signal corresponding to the reception current;
- a second amplifier connected to the first amplifier for amplifying the first voltage signal and generating a second voltage signal;
- a first gain control circuit connected to the first and second amplifiers for generating a first gain control signal based on the second voltage signal and adjusting the resistance value of the current-to-voltage conversion resistor in accordance with the first gain control signal;
- a bias control circuit connected to the first amplifier and the first gain control circuit for generating a bias control signal based on the gain control signal and adjusting the current at the output of the first amplifier in accordance with the bias control signal;
- and
- a second gain control circuit connected to the light-emitting element and the first amplifier for generating a second gain control signal based on the detection signal and adjusting the gain of the first amplifier in accordance with the second gain control signal.
Dependencies are inferred from the claim text.