Abstract: A laser apparatus includes a semiconductor laser of which a drive condition is controlled according to a plurality of types of drive currents and a controller which controls the drive condition such that a sum of the drive currents is equal to or less than a predetermined threshold value.

Abstract: A laser apparatus includes a semiconductor laser of which a drive condition is controlled according to a plurality of types of drive currents and a controller which controls the drive condition such that a sum of the drive currents is equal to or less than a predetermined threshold value.

Abstract: A light source driving apparatus, which adjusts a bias current to be supplied so as to control intensity of a light source, comprises a power source which outputs a variable reference voltage; a light receiving unit which receives light output from the light source and converts the light into an electric signal; a bias supply unit which supplies a bias current, which is based on an intensity control signal according to the electric signal converted by the light receiving unit and the reference voltage output from the power source, to the light source; and a voltage control unit which acquires information about intensity characteristics with respect to the intensity control signal of the light source and controls the reference voltage according to the acquired information about the intensity characteristics.

Abstract: A light source driving apparatus, which adjusts a bias current to be supplied so as to control intensity of a light source, comprises a power source which outputs a variable reference voltage; a light receiving unit which receives light output from the light source and converts the light into an electric signal; a bias supply unit which supplies a bias current, which is based on an intensity control signal according to the electric signal converted by the light receiving unit and the reference voltage output from the power source, to the light source; and a voltage control unit which acquires information about intensity characteristics with respect to the intensity control signal of the light source and controls the reference voltage according to the acquired information about the intensity characteristics.

Abstract: An optical apparatus comprises a phase comparator detecting a phase shift between a changing point of data transmitted through an electro/opto converter and a changing point of data received through an opto/electro converter, a delay controller and a variable delay circuit controlling a delay of the transmitted data so that the phase shift detected becomes equal to a value which minimizes a receiver sensitivity degradation due to crosstalks between a transmitter portion and a receiver portion.

Abstract: An apparatus is provided with a biasing unit supplying a bias signal to a first avalanche photodiode and a second avalanche photodiode, the bias signal having a first level and a second level, the first level causing a multiplying effect and the second level causing a non-multiplying effect for the first and the second avalanche photodiodes; a smoothing unit smoothing the bias signal biasing the first avalanche photodiode into a smoothed bias signal; a current detecting unit detecting photocurrent from the second avalanche photodiode, with a multiplying current value corresponding to the multiplying bias level and a non-multiplying current value corresponding to the non-multiplying bias level; a multiplication factor calculating unit calculating a multiplication factor of the second avalanche photodiode based on the multiplying current value and the non-multiplying current value; and a control unit controlling the first level of the bias signal based on the calculated multiplication factor.

Abstract: An apparatus is provided with a biasing unit supplying a bias signal to a first avalanche photodiode and a second avalanche photodiode, the bias signal having a first level and a second level, the first level causing a multiplying effect and the second level causing a non-multiplying effect for the first and the second avalanche photodiodes; a smoothing unit smoothing the bias signal biasing the first avalanche photodiode into a smoothed bias signal; a current detecting unit detecting photocurrent from the second avalanche photodiode, with a multiplying current value corresponding to the multiplying bias level and a non-multiplying current value corresponding to the non-multiplying bias level; a multiplication factor calculating unit calculating a multiplication factor of the second avalanche photodiode based on the multiplying current value and the non-multiplying current value; and a control unit controlling the first level of the bias signal based on the calculated multiplication factor.

Abstract: An optical apparatus comprises a phase comparator detecting a phase shift between a changing point of data transmitted through an electro/opto converter and a changing point of data received through an opto/electro converter, a delay controller and a variable delay circuit controlling a delay of the transmitted data so that the phase shift detected becomes equal to a value which minimizes a receiver sensitivity degradation due to crosstalks between a transmitter portion and a receiver portion.

Abstract: An apparatus for transmitting and receiving optical signals and which is independent of the optical transmission bit rate. The apparatus includes an optical transmitting unit and an optical receiving unit. The optical transmitting unit receives a clock signal and transmits an optical signal at a bit rate corresponding to the frequency of the clock signal. The optical receiving unit receives an optical signal, converts the received optical signal into an electrical signal and processes the electrical signal to be an electrical representation of the received optical signal. The optical receiving unit has frequency characteristics which are controllable in accordance with the frequency of the clock signal to control the processing of the electrical signal. For example, the optical receiving unit can include an amplifying unit which amplifies the electrical signal, wherein the gain and band of the amplifier are controllable in accordance with the frequency of the clock signal.

Abstract: The present invention alms at providing a low cost optical transmitter capable of controlling, with a high precision, fluctuations in optical output characteristic of a semiconductor light emitting device such as due to a temperature change.

Abstract: An apparatus for transmitting and receiving optical signals and which is independent of the optical transmission bit rate. The apparatus includes an optical transmitting unit and an optical receiving unit. The optical transmitting unit receives a clock signal and transmits an optical signal at a bit rate corresponding to the frequency of the clock signal. The optical receiving unit receives an optical signal, converts the received optical signal into an electrical signal and processes the electrical signal to be an electrical representation of the received optical signal. The optical receiving unit has frequency characteristics which are controllable in accordance with the frequency of the clock signal to control the processing of the electrical signal. For example, the optical receiving unit can include an amplifying unit which amplifies the electrical signal, wherein the gain and band of the amplifier are controllable in accordance with the frequency of the clock signal.

Abstract: A control circuit capable of accommodating individual characteristics and aging of laser diodes is provided. A laser diode control apparatus for controlling the light-emission output of a laser diode in accordance with temperature data, includes a driver circuit (12), connected to the laser diode, for supplying a drive current to the laser diode; a memory (18) capable of pre-storing respective drive current values appropriate under a plurality of temperature conditions for individual laser diodes; and a central processing unit (14), coupled to the memory, for controlling, via the driver circuit, the laser diode in accordance with the temperature data and the appropriate drive current value from the memory.

Abstract: The present invention aims at providing a low cost optical transmitter capable of controlling, with a high precision, fluctuations in optical output characteristic of a semiconductor light emitting device such as due to a temperature change.

Abstract: A device for driving a light emitting element, including a DC power source for generating a DC current, a signal driving unit for controlling, in an on-off manner, the DC current generated in the DC power source on the basis of signal data with timing in accordance with the signal data, a light emitting element which is driven by the DC current controlled in the on-off manner by the signal driving unit and emits light when the DC current flows thereto, a high-speed pulse controlling unit for controlling, in an on-off manner, the DC current which drives the light emitting element at a sufficiently short period in comparison with the signal data to pulse the DC current, and a driving control unit for controlling the timing of on-off control of the high-speed pulse controlling unit in accordance with a required mean optical output.