Patent application number | Description | Published |
20080226296 | Optical transmitter with suppressing wavelength deviation at begging of operation - 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 thermoelectric 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. | 09-18-2008 |
20080310851 | Optical transceiver with reduced peak power consumption and a method to reduce peak power consumption - 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. | 12-18-2008 |
20090194675 | OPTICAL RECEIVER APPLICABLE TO GPON SYSTEM - 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. | 08-06-2009 |
20100265076 | OPTICAL TRANSMITTER MODULE AND OPTICAL BI-DIRECTIONAL MODULE WITH FUNCTION TO MONITOR TEMPERATURE INSIDE OF PACKAGE AND METHOD FOR MONITORING TEMPERATURE - 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. | 10-21-2010 |
20100322271 | METHOD FOR DRIVING OPTICAL TRANSMITTER - 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. | 12-23-2010 |
20110292381 | METHOD FOR MEASURING OPTICAL INPUT POWER BY AVALANCHE PHOTODIODE - 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. | 12-01-2011 |
20120327964 | ALGORITHM TO DRIVE SEMICONDUCTOR LASER DIODE - 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. | 12-27-2012 |
20130219697 | METHOD TO PRODUCE OPTICAL TRANSCEIVER - 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. | 08-29-2013 |