Other

Opnext Japan, Inc.

Hitachi, Ltd.

Tadashi Hatano

Yasuhiro Yamada

Akihiro Hayami

Hiroo Matsue

Tomonao Kikuchi

Toshiaki Murai

Takayuki Nakao

Cleitus Antony

Tomokazu Tanaka

Tomoaki Shimotsu

Hidehiro Ikeuchi

Tohru Oyama

Tadaaki Fujii

Masayuki Miyoshi

Norio Chujo

Shigeru Tokita

Naohiko Baba

Fumihide Maeda

Hideyuki Serizawa

Yoichi Honzawa

Hideki Murakawa

Katsumi Saito

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 &#xb1;50% of a capacitance C&#x2248;L/Zo, where Zo is signal line impedance, and L is the signal lead inductance.

Optical transmitter

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.

Optical transmission module

An optical transmitter receiver module and an apparatus incorporating the same module are provided, which realizes the reduction of power consumption and the enlargement of the operating temperature range. As an example, an optical transmitter module is provided which comprises a light emitting element to generate a light signal, a signal processing circuit to transmit an electrical signal to the light emitting element and a voltage regulating circuit to lower a power voltage so as to supply the signal processing circuit with a constant voltage, wherein the module is further provided with a current regulating circuit to shunt a part of a current to be supplied into the voltage regulating circuit from a power source so as to generate a control current and a temperature controller to receive the control current so as to control a temperature of the light emitting element, wherein the module is further provided with a temperature detector to detect the temperature of the light emitting element and a temperature controlling circuit to control the control current according to an electrical signal output by the temperature detector.

Optical transmission module with light element temperature control

A temperature compensating circuit includes a first circuit network between an inverting input terminal of an operational amplifier and an output terminal of the operational amplifier , and a second circuit network between the inverting input terminal of the operational amplifier and a reference potential. At least one of the first circuit network and the second circuit network is made of an arrangement containing a plurality of series-connected thermistor/resistor pairs in which the thermistors are connected parallel to the resistors, and the temperature compensating circuit compensates a temperature-dependent signal which is inputted into a positive phase input terminal of the operational amplifier , and outputs the temperature-compensated signal.

Temperature compensating circuit, temperature compensating logarithm conversion circuit and light receiver

An optical transmitter includes a plurality of optical wavelength stability control apparatuses, each of which is capable of compensating for a wavelength drift by varying a laser diode drive current. Each of the optical wavelength stability control apparatuses detects a laser diode drive current, which is controlled by an auto power control circuit, by using a laser diode drive current detector. The laser diode drive current is normalized by a laser diode drive current increase/decrease normalization unit. A laser diode temperature control target value is generated at a compensated reference voltage generator, in response to the normalized laser diode drive current, to control a current value applied to a thermoelectric cooler so that an output value of a temperature monitor circuit approaches a predetermined laser diode temperature control target value.

Optical wavelength stability control apparatus, optical transmitter and multiple wavelength transmitter

A plurality of arms are successively connected to a fixed arm so that the free end of the connected arms is movable three-dimensionally, a direct-access endoscope is attached to the three-dimensionally movable free end of the arms, and angle sensors are provided in the individual arm joints. Changes in angles between the individual arms due to the movement of the front end of the direct-access endoscope are sensed by the angle sensors, and the size and position of the object are numerically determined according to the changes.

Position measuring device for endoscope

Growing community of inventors

Yokohama, Japan

Tadashi Hatano