US 6,324,198 B1Granted

Apparatus and method for compensating for temperature of laser diode

AssigneeSamsung Electronics Co., Ltd.

InventorTatsuhiro Otsuka

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Abstract

A temperature compensation apparatus for controlling an output power of a laser diode according to a temperature variation of the laser diode, and a method therefor. An error voltage between a voltage corresponding to the output power of the laser diode and a reference voltage is generated. The error voltage is output as a control voltage corrected based on the output power and is applied to the laser diode. When the level of the error voltage overflows or underflows in a first up/down counter, the control voltage based on the luminous efficiency of the laser diode is output by applying the corrected control voltage to the laser diode while interlocking the first up/down counter with a second up/down counter. Accordingly, it is possible to stabilize the luminous efficiency and reduce control error of the laser diode.

Claims8

Dependent claims

A temperature compensation apparatus of a laser diode, for controlling an output power of the laser diode by changing a control voltage according to a temperature variation of the laser diode, comprising:

a comparator to compare a voltage corresponding to the output power of the laser diode with a reference voltage, to generate an error voltage;
a first counter to count a first count value responsive to the error voltage, to generate a corrected error voltage, and to perform up and down counting of the first count value to change the corrected error voltage in response to a detection signal;
a detector to detect whether the first count value overflows or underflows, and to generate the detection signal in response to the first count value overflowing or underflowing;
a second counter to perform down and up counting of a second count value in response to the detection signal, in a reverse order to that of the first counter;
and
a control voltage generator to generate the control voltage based upon the corrected error voltage, and to add the first count value to the second count value when the first count value overflows or underflows to generate the control voltage as a uniform value.

3 more elements

A temperature compensation apparatus of a laser diode, comprising:

a voltage comparator to compare a voltage corresponding to an output power of the laser diode with a reference voltage, and to generate an error voltage;
a first up/down counter to count a first count value responsive to the error voltage, the first count value representing a variation in temperature of the laser diode, and to generate a corrected error voltage;
a detector to detect when the first count value overflows or underflows, and to generate a detection signal;
a second up/down counter to perform up and down counting of a second count value according to the detection signal, in a reverse order to that of the first up/down counter;
and
an adder to generate a control voltage based on the corrected error voltage, and to add the first count value to the second count value when the first count value overflows or underflows, which represents the variation in the temperature of the laser, to generate the control voltage responsive to the temperature variation as a uniform value;
and
a current converter to convert the control voltage into a current signal, and to apply the current signal to the laser diode.

5 more elements

Dependencies are inferred from the claim text.