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: An optical transceiver provides a TOSA, a ROSA, a base member, a circuit board and a shield member. The shield member is formed by cutting and bending a metal sheet without welding or soldering. The shield member includes a center partition and a pair of sides, which forms two spaces each receiving the TOSA or the ROSA. The center partition has a V-shaped cross section which is able to be inserted into a cut of the circuit board so as to shield the ROSA from the TOSA. The shield member provides a frame ground by being in the bottom of the center partition in contact with the base member and also in contact with the cover.

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: The present invention measures the frequency of occurrence of behaviors of a particular behavior for each time within a predetermined driving unit for each type of driving behaviors and causes the measured frequency of occurrence on a display unit as a driving evaluation index aimed at attaining a zero number each time the particular behavior takes place. Also, for each type of the driving behaviors, based on the frequency of occurrence of the particular behavior, which is a proportion of the number of occurrence of the particular behavior for each type relative to a predetermined driving time, which is the predetermined driving unit, the mean time between incidents of the particular behavior is calculated and the calculated mean time between the incidents is used as the driving evaluation index.

Abstract: An optical transceiver provides a TOSA, a ROSA, a base member, a circuit board and a shield member. The shield member is formed by cutting and bending a metal sheet without welding or soldering. The shield member includes a center partition and a pair of sides, which forms two spaces each receiving the TOSA or the ROSA. The center partition has a V-shaped cross section which is able to be inserted into a cut of the circuit board so as to shield the ROSA from the TOSA. The shield member provides a frame ground by being in the bottom of the center partition in contact with the base member and also in contact with the cover.

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.