Sumitomo Electric Industries, Limited

Sumitomo Electric Device Innovations, Inc.

Takeshi Irie

Toshio Mizue

Ichiro Tonai

Katsuyuki Takahashi

Daisuke Takagi

Kei Arakawa

Kazunori Kurima

Ryutaro Takei

Tomoki Ito

Kazuhisa Ozaki

Masatsugu Togasaki

Test equipment that is able to concurrently evaluate two or more optical modules each processing a wavelength multiplexed signal that multiplexes optical signals attributed to wavelengths different from each other. The test equipment provides a first test station and a second test station. After selecting one of the wavelengths, the first test station performs a first evaluation for an optical signal attributed to the one of the wavelengths and coming from the first optical module, and the second station concurrently performs a second evaluation for an optical single with the one of the wavelengths and coming from the second optical module. Thereafter, the first test station performs the first evaluation for the optical signal coming from the second optical module, while, the second test station performs the second evaluation for the optical signal coming from the first optical module.

Test equipment and process of evaluating optical modules

New method to control the optical transmitter is disclosed. The optical transmitter provides both of the ATC feedback loop and the APC feedback loop. When a failure occurs in the ATC feedback loop and the temperature sensor is unable to output an adequate signal any longer, the optical transmitter cuts the APC loop and operates the LD in constant conditions. The output of the monitor PD is transferred to the ATC loop to control the TEC based on the optical output of the LD.

Method to control temperature of LD

A control circuit for a laser diode is disclosed, in which the driving current may be suppressed even when the monitor PD breaks down to make the APC feedback control inoperable. The control circuit comprises an LD driver to supply the driving current to the LD, a monitor PD to detect a portion of output light from the LD, and the APC controller to adjust the driving current. The current limiter, when the driving current reaches or exceeds the threshold, controls the driving current Id so as to keep the current in a preset value or a value just before the extraordinary increase of the driving current occurs.

Control circuit for a laser diode and a method to control a laser diode

An optical receiver circuit is provided which is able to receive optical signals having a variable transmission rate, without loss of data. The optical receiver circuit according to the present invention has a light-receiving section for converting an optical signal with a variable transmission rate into an electric signal. A recovery section recovers a plurality of different clock signals and data corresponding to possible transmission rates. These data are stored into a plurality of memories and at the same time a decision section decides the transmission rate. A switch section reads data from one of the memories selected according to the result of the decision.

Optical receiver circuit applicable to multiple transmission rates

The present invention provides an optical receiver in which a signal detection level is independent on whether a ammeter is connected to a current monitor terminal or not. The optical receiver comprises a photo diode, a first current mirror circuit connected to the photo diode and a second current mirror circuit. The second current mirror circuit has a pair of current path, one of which is connected to the first current mirror circuit and the other of which is connected to the voltage source provided within the optical receiver. The voltage source supplies a bias whether an ammeter is connected to the other of the current path or not. Therefore, the signal detection level attributed to one of the current path is unchanged.

Optical receiver

The present invention provides an optical module capable of reducing the amount of electrostatic charges on a shielding member. The optical module comprises an assembly portion and a shielding member. The assembly portion includes a light receiving device, an electronic element, a circuit board, and a plurality of terminals. The light receiving device includes a semiconductor optical element. The semiconductor optical element is optically coupled to an optical connector. The electronic element is electrically connected to the semiconductor optical element. The circuit board mounts the electronic element thereon. The plurality of terminals is electrically connected to the circuit board. The shielding member includes a reference terminal provided so as to be connected to a reference potential line, and shields the assembly portion. In this optical module, the assembly portion is provided with an electrically conductive piece provided so as to connect the shielding member to at least one of the plurality of terminals.

Optical module

The present invention relates to an optical module or the like having a structure which prevents the efficiency in a sleeve securing operation or optical characteristics from deteriorating and improves adhesion durability. In particular, a resin mold portion including an optical device in the optical module according to the present invention is processed into a shape which can directly irradiate the UV-curable resin introduced between the resin mold portion and the sleeve with ultraviolet rays, and a structure for restricting the flow of the resin changing into a flowing state during the sleeve securing operation or a structure for improving the adhesion durability of the sleeve is provided on at least one of the sleeve side and resin mold portion side.

The present invention relates to an optical data link having a structure which is quite easy to manufacture at a low cost and realizes high optical accuracy, high mechanical accuracy, and high reliability. This optical data link comprises a light-receiving module for outputting an optical signal from an optical fiber transmission line as an electric signal, and a light-emitting module for transmitting the optical signal to the optical fiber transmission line. Each of these optical modules comprises a body portion including an electronic device; a head portion including a light-receiving device or light-emitting device; and a neck portion, processed into a predetermined form, for communicating the body portion and head portion to each other. The optical modules are mounted on an insulating substrate, and are at least partly accommodated in a housing, while being separated from each other by a predetermined distance.

Growing community of inventors

Yokohama, Japan

Takeshi Irie