Abstract: An optical module includes an electromagnetic wave absorption member. The electric connection member includes a floating portion which is in a floating state spaced apart from the housing and at a position away from a mounting portion by which the electric connection member is mounted on the housing in the direction opposite to the direction that the optical module is inserted into a cage. At least a portion of the electromagnetic wave absorption member is arranged between the housing and the floating portion. The floating portion is brought into contact with an inner side of the cage so as to establish the electrical connection with the inner side of the cage when the housing is inserted into the cage.

Abstract: An optical module includes an electromagnetic wave absorption member. The electric connection member includes a floating portion which is in a floating state spaced apart from the housing and at a position away from a mounting portion by which the electric connection member is mounted on the housing in the direction opposite to the direction that the optical module is inserted into a cage. At least a portion of the electromagnetic wave absorption member is arranged between the housing and the floating portion. The floating portion is brought into contact with an inner side of the cage so as to establish the electrical connection with the inner side of the cage when the housing is inserted into the cage.

Abstract: Provided is an optical transmission circuit capable of realizing a high-quality optical signal waveform with low power consumption. An optical transmission circuit (10) includes: a laser diode (800); a modulator (900) for supplying a differential modulation current to an anode terminal and a cathode terminal of the laser diode (800) through transmission lines (301 to 304); a current source (101) for supplying a forward bias current to the laser diode (800); and a magnetic sheet (wave absorber) (400) disposed so as to cover at least a part of the transmission lines (303 and 304). An impedance of the laser diode (800) is lower than characteristic impedances of the transmission lines (301 to 304) which are formed so that the characteristic impedances thereof are matched to an output impedance of the modulator (900).

Abstract: The invention provides a heat radiating structure which reduces a mechanical stress applied to an electronic part mounted on a printed circuit board including a semiconductor package. The heat radiating structure is constructed by a semiconductor package mounted on a printed circuit board, a thermal conduction sheet arranged on an upper surface of the semiconductor package, and a metal case provided with a heat radiating fin for receiving a heat transmitted form the thermal conduction sheet so as to discharge to an atmospheric air, and the metal case is provided with a concavo-convex structure in a contact portion with the thermal conduction sheet.

Abstract: An optical transmission module mounted pluggably to a cage having an opening. The optical transmission module comprises a gasket on at least a part of an outer periphery of the module. The gasket is deformed depending on temperature change. The gasket is deformed according to temperature rise in a direction toward an inner wall of the cage to push the inner wall and deformed according to temperature drop in an opposite direction to the direction.

Abstract: A master station includes a group of circuits for performing an optimization method. In such a system, the optimization is achieved by adjusting the pull-up resistance and by setting the best possible clock frequency to ensure that data/clock high and low voltage levels are within predetermined specifications. An optimization procedure is performed in a calibration phase invoked by a user or a system whenever a change is introduced to the system, such as addition or deletion of slave stations, a change of data/clock lines, or a change that may affect on the electrical and timing characteristics of the two-wire communication system.

Abstract: An optical transceiver module for transmitting and receiving an optical signal with a plurality of channels includes timing generator for sequentially generating timing instructions defining different start-up time points, and powering controller for effecting a control such that power supply to at least a portion of circuit components associated with the respective channels is sequentially started in accordance with the timing instructions generated by the timing generator. Current to be instantaneously necessitated when a power switch is turned on or when a power restoration is made from power saving operation modes can be suppressed.

Abstract: Provided is an optical transmission circuit capable of realizing a high-quality optical signal waveform with low power consumption. An optical transmission circuit (10) includes: a laser diode (800); a modulator (900) for supplying a differential modulation current to an anode terminal and a cathode terminal of the laser diode (800) through transmission lines (301 to 304); a current source (101) for supplying a forward bias current to the laser diode (800); and a magnetic sheet (wave absorber) (400) disposed so as to cover at least a part of the transmission lines (303 and 304). An impedance of the laser diode (800) is lower than characteristic impedances of the transmission lines (301 to 304) which are formed so that the characteristic impedances thereof are matched to an output impedance of the modulator (900).

Abstract: A reader/writer is provided which is capable of speedily recognizing a correspondence between one end and the other end of a fiber-optic cable when a plurality of fiber-optic cables is laid. The reader/writer according to the present invention reads, on receiving through the fiber-optic cable a signal that is an instruction to read data from a RF tag mounted to an end of the fiber-optic cable, data from the RF tag through radio communication, and transmits the read data through the fiber-optic cable. Also, on receiving through the fiber-optic cable a signal that is an instruction to write data into the RF tag and a signal indicating the write data, the reader/writer writes the write instruction and the write data into the RF tag through radio communication.

Abstract: The invention provides a heat radiating structure which reduces a mechanical stress applied to an electronic part mounted on a printed circuit board including a semiconductor package. The heat radiating structure is constructed by a semiconductor package mounted on a printed circuit board, a thermal conduction sheet arranged on an upper surface of the semiconductor package, and a metal case provided with a heat radiating fin for receiving a heat transmitted form the thermal conduction sheet so as to discharge to an atmospheric air, and the metal case is provided with a concavo-convex structure in a contact portion with the thermal conduction sheet.

Abstract: An optical transmission module mounted pluggably to a cage having an opening. The optical transmission module comprises a gasket on at least a part of an outer periphery of the module. The gasket is deformed depending on temperature change. The gasket is deformed according to temperature rise in a direction toward an inner wall of the cage to push the inner wall and deformed according to temperature drop in an opposite direction to the direction.

Abstract: In an optical transmitter, a light-emitting device, a modulator that outputs a differential modulation current via alternating current coupling capacitors to an anode terminal and a cathode terminal of the light-emitting device, a first current source between the cathode terminal and a ground line (GND) of the light-emitting device, and a second current source between the anode terminal and a power source line (Vcc) of the light-emitting device, are provided.

Abstract: A reader/writer is provided which is capable of speedily recognizing a correspondence between one end and the other end of a fiber-optic cable when a plurality of fiber-optic cables is laid. The reader/writer according to the present invention reads, on receiving through the fiber-optic cable a signal that is an instruction to read data from a RF tag mounted to an end of the fiber-optic cable, data from the RF tag through radio communication, and transmits the read data through the fiber-optic cable. Also, on receiving through the fiber-optic cable a signal that is an instruction to write data into the RF tag and a signal indicating the write data, the reader/writer writes the write instruction and the write data into the RF tag through radio communication.

Abstract: A master station includes a group of circuits for performing an optimization method. In such a system, the optimization is achieved by adjusting the pull-up resistance and by setting the best possible clock frequency to ensure that data/clock high and low voltage levels are within predetermined specifications. An optimization procedure is performed in a calibration phase invoked by a user or a system whenever a change is introduced to the system, such as addition or deletion of slave stations, a change of data/clock lines, or a change that may affect on the electrical and timing characteristics of the two-wire communication system.

Abstract: An optical transmitter in which a microstripline is formed by a signal wiring pattern and a GND conductor pattern on a circuit board (including a flexible board), and a signal lead of a light emitting element module is mounted in a signal lead mounting hole connected with said signal wiring pattern so as to be connected with said signal wiring pattern, wherein a pattern adapted to add capacitance between a stem of said light emitting element module and said signal wiring pattern is provided on said signal wiring pattern on said circuit board, and wherein the pattern adapted to add capacitance has a size corresponding to ±50% of a capacitance C?L/Zo2, where Zo is signal line impedance, and L is the signal lead inductance.

Abstract: The present invention provides an optical transmission module having a laser diode that generates laser beams and a differential type current switch provided with a first switch and a second switch in order to supply a modulating current to the laser diode. A terminal of the laser diode and the first switch are connected in series through a first transmission line and a first capacitor, the other terminal of the laser diode and the second switch are connected in series through a second transmission line and a second capacitor. The current driven by the second switch is terminated by a resistor connected to the first switch and the current driven by the first switch is terminated by a resistor connected to the second switch. Thus, the laser diode is modulated bidirectionally.

Abstract: An optical transmitter in which a microstripline is formed by a signal wiring pattern and a GND conductor pattern on a circuit board (including a flexible board), and a signal lead of a light emitting element module is mounted in a signal lead mounting hole connected with said signal wiring pattern so as to be connected with said signal wiring pattern, wherein a pattern adapted to add capacitance between a stem of said light emitting element module and said signal wiring pattern is provided on said signal wiring pattern on said circuit board, and wherein the pattern adapted to add capacitance has a size corresponding to ±50% of a capacitance C?L/Zo2, where Zo is signal line impedance, and L is the signal lead inductance.

Abstract: The present invention provides an optical transmission module having a laser diode that generates laser beams and a differential type current switch provided with a first switch and a second switch in order to supply a modulating current to the laser diode. A terminal of the laser diode and the first switch are connected in series through a first transmission line and a first capacitor, the other terminal of the laser diode and the second switch are connected in series through a second transmission line and a second capacitor. The current driven by the second switch is terminated by a resistor connected to the first switch and the current driven by the first switch is terminated by a resistor connected to the second switch. Thus, the laser diode is modulated bidirectionally.