Sumitomo Electric Industries, Limited

Victor Company of Japan, Limited

Naoki Nishiyama

Shunsuke Sato

Mitsuaki Nishie

Satoshi Takahashi

Katsumi Uesaka

Asako Kato

Kenji Tanaka

Hideki Yamanaka

The present invention provides an optical module with a relatively wider mounting area for the devices with a CAN package. The optical module of the present invention provides the stem and the cap, both of which form a cavity where the devices are to be installed. The stem provides the block extruding from the primary surface of the stem into the cavity. The block mounts the optical and electrical devices in surfaces opposite to each other, and provides feedthrough pins between these two surfaces. The device mounted in each surface may be electrically connected through these feedthrough pins.

Optical module having a block with feedthrough pins

An optical device with a CAN package is disclosed, where the cap is resistance-welded to the stem without causing failures due to fragments by the welding flying within the package. The cap of the invention has a flange portion to be welded to the stem. The flange portion provides a ringed groove in addition to the ringed projection for the welding. The fragment due to the welding may be captured in the ringed groove and is prevented from flying within the package. The ringed groove and the ringed projection are simultaneously formed in the stamping to form the body portion of the cap.

Metal cap with ringed projection to be welded to stem and ringed groove provided immediately inside of ringed projection and optical device having the same

The present invention provides a laser diode driving circuit able to reduce the degradation of the optical output from the laser diode even when the characteristic of the laser diode widely scatters. The circuit provides a filter circuit connected in parallel to the laser diode that compensates the frequency dependence of the laser diode. In the invention, the frequency characteristic of this filter circuit may be varied depending on the scattering in the frequency response of the laser diode, or on the temperature characteristic of the diode.

Laser driver circuit able to compensate a temperature dependence of the laser diode

The present invention provides an optical transceiver to reduce a crosstalk in sufficient. The optical receiving unit of the invention includes an O/E-converter, a signal processing unit, and an offset voltage setting unit. The input of the signal processing unit, connected to the output of the O/E-converter, receives an electrical signal from the O/E-converter. The offset voltage Vof the signal processing unit is kept constant, independent of the phase difference between signal in the optical transmitting unit and in the optical receiving unit, by the offset voltage setting unit.

Optical receiving unit reducing cross talk between optical transmitting unit and optical transmitting/receiving apparatus installing the same

The present invention is to provide an LD-driver that enables to adjust the waveform of the driving current to the LD even the driver is constituted with a current controlled device such as bipolar transistor. The LD-driver of the invention provides a plurality of modulation current sources each having a function to set the amplitude, the phase and the pulse width of the current output independently. The LD is provided with the modulation current superposed with each current derived from respective current sources.

Laser diode driver with multiple modulation current source

The present invention provides an optical receiver operable for optical signals each having different transmission speed. The optical receiver includes a light-receiving device, a pre-amplifier, a main amplifier, and a control circuit. The pre-amplifier, may be a trans-impedance amplifier, includes a parallel connection of a switching device and a resistor in a trans-impedance or a load element. By switching ON/OFF the switching device, the gain and the bandwidth of the pre-amplifier may be changed. By providing a filter circuit, whose cut-off frequency may be switched, in the main amplifier, the bandwidth of the optical receiver may be varied.

Optical receiver for an optical communication

This invention provides an optical receiver, a temperature dependence of which is compensated, and a method for manufacturing the optical receiver. The optical receiver according to the present invention comprises an avalanche photodiode (APD), a voltage source for supplying a bias voltage to the APD and a controller for feedback-controlling the bias voltage based on the monitored temperature of the APD. The input of the controller changes as the temperature of the APD varies, such that the bias voltage to the APD compensates the temperature dependence thereof. One aspect of the invention is that the reference input to the controller depends on the temperature, while another aspect of the invention is that the dividing ratio of the bias voltage changes as the temperature of the APD varies.

Optical receiver and a method for manufacturing the same

The present invention provides a light-receiving circuit that applies the avalanche photodiode (APD) and reduces the power consumption at a large optical input. The bias controlling circuit of the present invention provides a voltage source, a current detector, a voltage divided, and a controller. The current detector detects the photo current generated by the APD and output the current or voltage signal corresponding to the photo current. The voltage divider divides the output of the voltage source and the current or voltage signal from the current detector thereof may affect the dividing ratio. The controller operates to maintain the output of the divider constant by adjusting the output of the voltage source. Accordingly, the output of the voltage source decreases at the high optical input, thereby reducing the power consumption of the circuit.

Light receiving circuit using avalanche photodiode with a controlled voltage divider

An optical data linkcomprises a mounting member, an optical element assembly, a circuit board, and a spacer. The PGA substratehas a substrateand a plurality of electrically conductive pins. The circuit boardhas a pair of surfaces. Electronic componentstoare mounted on the pair of surfaces. The optical element assemblyincludes a semiconductor optical element. The semiconductor optical elementis connected to an electrically conductive layer on the circuit board. The spacerfunctions so as to distance the circuit boardfrom the PGA substrate. Since the circuit boardis distanced from the PGA substrate, the electronic componentstocan be mounted on both surfaces of the circuit board

Optical data link

This optical module comprises a photodiode,, a current mirror circuit,having two parallel lines, one of the lines being connected to the photodiode,, and a transimpedance amplifier,connected to the photodiode,. Since the current mirror circuit,is provided, the photocurrent from the line flows into the photodiode,and amplified by the transimpedance amplifier,. This photocurrent is observed as a current flowing out of the other line of the current mirror circuit

Optical module for receiving optical signal from optical fiber

Since this photocurrent monitor circuit can detect, by way of first and second current mirror circuits,F,,R, a current proportional to the photocurrent flowing into a photodiode,from a photocurrent monitor terminal IMT, it can monitor the correct photocurrent without its detecting circuit influencing the photocurrent of the photodiode itself.

Photocurrent monitor circuit and optical receiver

A first image is formed with at least a first color included in a first coloring system and corresponding to first color signal data converted from second signal data corresponding to at least a second color included in a second coloring system and related to an original image. At least a color modification parameter corresponding to a difference between the first color and a third color related to the original image. The color modification parameter is optimized to calculate a first area to be modified and a first amount to be modified with respect to the original image. A second image is formed using the second color signal data on the basis of the first area and amount to be modified and another first image already formed. Next, a third image is formed using the first color signal data, the third image corresponding to the second color. And, the second and third images are synthesized to form the first image.

Method and apparatus for color reproduction

The photocurrent generated by a photodiode receiving light substantially flows through a feedback resistor when the incident light intensity is low. As the incident light intensity increases, the source and drain of a FET connected in parallel to the feedback resistor establish a conducting state therebetween, whereby the photocurrent is divided into a current flowing through the feedback resistor and a current flowing through the FET connected in parallel to the feedback resistor. Accordingly, transimpedance is equivalently lowered, while the feedback resistor is restrained from lowering the output potential. When the incident light intensity is further increased, a gate bias current flows into the gate of an input-stage FET of an amplifier, whereby the photocurrent is divided into the current flowing through the feedback resistor, the current flowing through the FET connected in parallel to the feedback resistor, and the gate bias current. Accordingly, the preamplifier can operate even under a larger optical input. Thus realized is a novel configuration of a preamplifier for optical communication, from which a stable operation is expected even when the power supply voltage is lowered and which can operate at a single power source voltage as well.

Preamplifier for optical communication

A photodetector module contains a package, a photodiode, a preamplifier, a bypass capacitor, a cap with a lens and a sleeve. A parallel plate capacitor is used as the bypass capacitor. The parallel plate capacitor is mounted at the center of the package. The photodiode is stuck on the parallel plate capacitor. Since the photodiode is piled upon the capacitor, the module curtails the area for mounting a capacitor. The fiber, the lens, the photodiode and the capcitor align along a central line with rotational symmetry. The two-story structure reduces the size of the module and the cost of production by decreasing the number of the parts and the steps of production.

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Yokohama, Japan

Naoki Nishiyama