Abstract: A method to control an optical transceiver, in particular, to drive an LD installed within the optical transceiver is described. The LD in the bias current thereof is determined by the automatic power control (APC) loop to keep an average of the optical output power. The modulation current is determined by a feedback loop to keep the extinction ratio (ER) in a preset range. The initial condition of the modulation current for the feedback loop is set by T-Im characteristic. The T-Im characteristic is first derived based on data measured in a status of the LD not installed in the transceiver. The T-Im characteristic is revised timely by the modulation current practically obtained for the optical transceiver.

Abstract: A method to monitor an output of an APD is disclosed. The method includes steps of, (a) measuring dark currents of the APD at several temperatures in advance to a practical operation of the APD, (b) measuring an output current of the APD by illuminating the APD practically at a measured temperature, (c) estimating a dark current at the measured temperature from measured dark currents, and (d) subtracting the estimated dark current from the output current.

Abstract: An algorithm to drive a semiconductor laser diode (LD) is disclosed. The algorithm assumes that the modulation current to keep the extinction ratio in constant has temperature dependence represented by an exponential function under the average output power of the LD is kept constant by an auto-power-control (APC). When a tracking error exists and the approximation by an exponential function is turned out in failure, the algorithm adds a correction to the exponential function determined by a difference between a practically measured modulation current and another modulation current calculated from a value determined for a bared LD.

Abstract: A method to control an LD (laser diode) is disclosed. The method compares the operating temperature of the LD with a transition temperature. When the former temperature exceeds the latter, the modulation current is set based on the bias current, which is independently determined by the APC loop. On the other hand, the operating temperature is less than the transition temperature; the modulation current is determined by the operating temperature.

Abstract: An algorithm to drive a semiconductor laser diode (LD) is disclosed. The algorithm assumes that the modulation current to keep the extinction ratio in constant has temperature dependence represented by an exponential function under the average output power of the LD is kept constant by an auto-power-control (APC). When a tracking error exists and the approximation by an exponential function is turned out in failure, the algorithm adds a correction to the exponential function determined by a difference between a practically measured modulation current and another modulation current calculated from a value determined for a bared LD.

Abstract: A biosensor measurement device for providing accurate measurement results within a short period of time by using only a very small amount of sample. The biosensor measurement device includes a power source, which is connected to a voltage regulator, a measurement instrument, and a controller for supplying power. When the biosensor chip is connected to the biosensor measurement device and a voltage is applied, the measurement instrument begins the measurement of a current value for the biosensor. When the measured current value or a measured charge value is greater than a reference value, the measurement is terminated in accordance with an instruction issued by the controller, and when the value is smaller than the reference value, the measurement is continued in accordance with a controller instruction.

Abstract: An optical receiver is disclosed, in which no additional photodiode to monitor the optical input level and no temperature control unit are necessary. The receiver of the invention provides an avalanche photodiode (APD) to receiver the first optical signal with the first wavelength and a PIN-PD to receive the second optical signal with the second wavelength. The optical input level for the APD is indirectly determined through the photocurrent generated by the PIN-PD and the bias voltage for the APD is so adjusted that the APD shows an optimum multiplication factor for the optical input level.

Abstract: A method to reduce a peak power consumption of an optical transceiver including a thermoelectric cooler (TEC) is disclosed. The transceiver includes three power units, one of which powers the temperature control unit including the TEC driver and the TEC, second one of which powers the transmitter unit including an LD and an LD driver, and the last of which powers the receiver unit. Once the transceiver is set in the host system, the transceiver first activates the first and second power units to start up the temperature control unit and the transmitter unit, and subsequently, the transceiver sets up the third power unit after the temperature of the LD is stabilized at a target temperature.

Abstract: A method to monitor an output of an APD is disclosed. The method includes steps of, (a) measuring dark currents of the APD at several temperatures in advance to a practical operation of the APD, (b) measuring an output current of the APD by illuminating the APD practically at a measured temperature, (c) estimating a dark current at the measured temperature from measured dark currents, and (d) subtracting the estimated dark current from the output current.

Abstract: An optical transmitter is disclosed in which the wavelength deviation occurred at the turning on from the disabled state to the enabled state by the negating of the Tx_Disable command is suppressed. The optical transmitter includes a semiconductor laser diode (LD) and an automatic temperature controller (ATC) circuit to drive the thermo-electric cooler (TEC). When the transmitter receives the Tx_Disable to start up the operation of the LD, a pulsed signal is generated in synchronizing with the transition of the Tx_Disable signal to momentarily enhance the cooling capacity of the TEC in order to compensate the increase of the temperature of the LD by the self heating, which prevents the output wavelength of the transmitter from deviating.

Abstract: In a biosensor system and its measuring instrument which determine that a biosensor chip has been inserted and measure biological information on a biological material supplied to the biosensor chip, the size of the biosensor chip is made small, the reliability of the measuring instrument is improved, and the product life becomes long. In addition, a measurement error of the biological information is suppressed in measuring the biological information by inserting a biosensor chip, which has a sensor electrode formed of an electrode member with an electric resistance value higher than a conductive metal, into the measuring instrument.

Abstract: A method to control an LD (laser diode) is disclosed. The method compares the operating temperature of the LD with a transition temperature. When the former temperature exceeds the latter, the modulation current is set based on the bias current, which is independently determined by the APC loop. On the other hand, the operating temperature is less than the transition temperature; the modulation current is determined by the operating temperature.

Abstract: An optical module with a function to monitor a temperature within the package without installing any specific temperature sensing device is disclosed. The optical module of the invention includes an LD and a monitor PD in a CAN type housing. When the LD is inactive or driven under a constant bias current, the monitor PD receives a constant current independent of the temperature. The forward voltage of the monitor PD indicates the temperature within the package.

Abstract: An optical receiver of the present embodiment has a light-receiving block, a discriminating block, a detecting block, a controlling block, and an adjusting block. The light-receiving block generates complementary signals in accordance with a photo current output from a semiconductor light-receiving element which receives an optical signal. The discriminating block has a differential amplifier having input terminals connected to output terminals of the light-receiving block via respective coupling capacitors. The detecting block generates an intensity signal corresponding to the photo current. The controlling block generates a first signal in accordance with a dispersion signal corresponding to dispersion of an optical transmission line, a distance signal corresponding to the distance of the optical transmission line, and an intensity signal.

Abstract: In a biosensor system and its measuring instrument which determine that a biosensor chip has been inserted and measure biological information on a biological material supplied to the biosensor chip, the size of the biosensor chip is made small, the reliability of the measuring instrument is improved, and the product life becomes long. In addition, a measurement error of the biological information is suppressed in measuring the biological information by inserting a biosensor chip, which has a sensor electrode formed of an electrode member with an electric resistance value higher than a conductive metal, into the measuring instrument. An electrode portion provided in an insertion portion 5 of a measuring instrument 1 is configured such that a ground electrode 12 is used in both a sensor insertion determining circuit 14 and a blood sugar level measuring circuit 15.

Abstract: It is intended to provide a sensor chip which has a small size and is easily produced and capable of determining quantities of at least two components of multiple samples rapidly, conveniently, and correctly as well as to provide a production method capable of producing the sensor chip easily and with high productivity. A sensor chip includes a substrate, a cover layer, a spacer layer sandwiched between the substrate and the cover layer, multiple reaction portions disposed between the substrate and the cover layer, multiple detection units exposed in the hollow reaction portions, and a sample inlet communicated with the hollow reaction portions and a method for producing the sensor chip.

Abstract: An optical receiver is disclosed, in which no additional photodiode to monitor the optical input level and no temperature control unit are necessary. The receiver of the invention provides an avalanche photodiode (APD) to receiver the first optical signal with the first wavelength and a PIN-PD to receive the second optical signal with the second wavelength. The optical input level for the APD is indirectly determined through the photocurrent generated by the PIN-PD and the bias voltage for the APD is so adjusted that the APD shows an optimum multiplication factor for the optical input level.

Abstract: Provided are a biosensor chip measurement machine that can obtain accurate measurement results within a short period of time by employing only a tiny amount as a sample, and a measurement method therefor. A biosensor measurement machine 20 includes a power source 21, which is connected to a voltage regulator 22, a measurement instrument 23, and a controller 24 for supplying power. When a biosensor chip 1 is connected to the biosensor measurement machine 20 and a voltage is applied, the measurement instrument begins the measurement of a current value for a biosensor. When a measured current value or a measured charge value is greater than a reference value, the measurement is ended in accordance with an instruction issued by the controller 24, and when the value is smaller than the reference value, the measurement is continued in accordance with a controller instruction.

Abstract: The present invention provides an optical transmitter that prevent the overshoot and undershoot appeared in the emission wavelength caused by the fluctuation of the temperature of the laser diode installed therein. The optical transmitter includes a TEC driver, and a master controller. The TEC driver, by comparing the monitored temperature with the target temperature, outputs the error signal to the master controller, which enables the LD-Driver only when the error signal continuously stays within a convergent range by a preset period.

Abstract: It is intended to provide a sensor chip that enables detection of a deterioration state of a reagent applied on a reaction portion when measuring a concentration of a measurement object substance and a sensor system that enables a correct measurement by using the sensor chip for detecting the reagent deterioration state. A sensor chip including two substrates opposed to each other, a spacer layer sandwiched between the substrates, a multiple reaction portions provided in the spacer layer, and detection electrode units disposed on surfaces of the substrates facing to the spacer layer and exposed to the reaction portions, wherein an identical reagent A is applied on two or more of the reaction portions, and another reagent B that reacts with the reagent A is applied on at least one of the two reaction portions and a sensor system including the sensor chip and a measurement unit for comparing current values from the two or more reaction portions on which the identical reagent A is applied.