Abstract: An optical transmission module with an optical device mounted in a substrate provided with an optical waveguide is provided wherein respective metallic electrodes in pair are symmetrically disposed in each side of an optical device divided by a centerline parallel to an optical axis such that those electrodes have an error of 60 ?m or less and said metallic electrodes are soldered to a metallic electrode as disposed on a substrate, which electrode has a size enough to cover those electrodes as disposed in the optical device.

Abstract: According to the present invention there are provided a transmission line and an optical module having the transmission line, the transmission line having on a dielectric substrate a first signal wiring conductor, a second signal wiring conductor insulated from the first signal wiring conductor, a first electrode disposed near the first and second signal wiring conductors, a second electrode disposed near the second signal wiring conductor, and a ground wiring conductor disposed in adjacency to the second electrode, wherein a passing frequency band can be changed by changing the connection of conductor wires.

Abstract: The provision of a coplanar waveguide coupled with a microstrip line with a transmission line substrate that is used between two functional units of different impedance characteristics allows the input and output impedance matching to be performed, the impedance matching between which coplanar waveguide and microstrip line is performed by the variation of the signal linewidth. It allows the transmission characteristics of the optical transmission device in high frequency band to improve.

Abstract: The present invention provides a polarization dependency-free, gain-saturated high function semiconductor optical amplifier and optical module at industrially low cost. The gist of the present invention is to structurally separate the optical signal propagating waveguide from another optical waveguide which serves as a lasing optical cavity for optical amplification in such a manner that the two optical waveguides are formed in the same plane but not parallel to each other.

Abstract: The present invention provides an optical transmission module configured such that a driver IC chip to drive a semiconductor laser device, a first insulation plate having the semiconductor laser device mounted thereon and a coupling optical component are mounted in this order, a thin film inductor element and thin film resistor element which are connected in parallel are formed on a second insulation plate and a bias current is supplied to the semiconductor laser device via this LR element.

Abstract: The present invention relates to an optical transmission module comprising two substrates, each of which has an electronic part mounted on the substrate and a terminal area for inputting/outputting an electric signal into/from the electronic part, wherein an electrical connection is made between the terminal areas of said two substrates by use of a flexible substrate having a structure constituted of at least three layers, and thereby a high frequency signal is transmitted between the electronic part mounted on one substrate and the electronic part mounted on the other substrate through the flexible substrate while confining an electromagnetic field.

Abstract: The present invention provides an optical module, and an optical transmission line comprising the optical module. The optical module has a structure in which an optical-modulator-mounted carrier is formed of a semiconductor substrate; a transmission line on the carrier is formed of a coplanar waveguide; a transmission line for inputting a signal into the transmission line is formed on a dielectric substrate; the transmission line on the input side which is a grounded coplanar waveguide is coupled by a conversion line to the transmission line on the output side which is a coplanar waveguide; and an electrical connection between the transmission lines is made by use of a conductor wire.

Abstract: An optical modulator having a good reflection characteristic over a broad band is provided, with a small semiconductor chip area, by use of a semiconductor chip on which a semiconductor optical modulator is mounted. A typical example of the optical modulator has a structure in which a semiconductor chip provided with an electro-absorption semiconductor optical modulator comprising an electrode of traveling wave modulator is mounted on a dielectric substrate provided with a transmission line, and the characteristic impedance of at least a part of the transmission line is set to be greater than the output impedance of a modulator driver circuit and the impedance of an optical modulator portion. By this, a broad band optical modulator with excellent reflection characteristic can be provided by use of a semiconductor chip which is small in area.

Abstract: A driver circuit comprises a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply. Different electric potentials are applied to the bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about 1/100 or smaller. An amplitude of an output current is controlled by the higher of the electric potentials applied to the base of one of the first transistors.

Abstract: The present invention provides an optical module and a method for manufacturing the optical module, in which a V-shaped or trapezoidal groove having a first slope and a second slope facing to the first slope is formed at the surface of a silicon substrate by anisotropic etching, an adhesive is applied to a portion of at least the second slope in a region except the first slope of the groove, and lens is fixedly put in the groove.

Abstract: Conventionally, in the wavelength locking optical system, the wavelength as detected is deviated from a targeted range owing to the change of the peripheral temperature resulting from the temperature characteristics of the wavelength error detection device. To solve this prior issue, it is arranged such that a portion of the wavelength error detection device, through which portion light-beams passes, contacts a material of high heat conductivity.

Abstract: In an optical coupling apparatus, an optical isolator and an optical fiber are arranged inside a pipe of a side surface of a package. A distal end of the optical fiber is arranged within a range of 3.0 mm from an inner/outer surface of the side surface of the package and a distance from a laser diode to the distal end is within a range from 3.5 to 7.5 mm. Distance from the inner side surface of the package to a Peltier device is within a range of 6.0 mm. A metallize pattern film applied to a terminal substrate of the package and the Peltier device are connected through wiring bonding and a connection position is closer to the optical fiber than a lead terminal provided to the terminal substrate of the package that corresponds to the Peltier device.

Abstract: The invention provides a manufacturing method of a laser diode having buried grown layer with less crystal defects and with low consumption power and having high reliability in a buried heterostructure laser diode using an InGaAlAs type material as an active layer, by preventing the inhibition of burying and regrowing of the active layer caused by oxidation of Al contained in the active layer. A manufacturing method of a semiconductor laser diode and the active layer comprises a material at least containing Al and having a buried hetero-cross sectional structure, formation of the buried heterostructure, comprising the steps of fabricating the active layer into a stripe shape or mesa shape by etching including at least wet etching, cleaning the stripe-shape sidewall of the core layer with a gas containing chlorine or other halogen element in a crystal growing apparatus and burying the active layer in the semiconductor.

Abstract: A PD (20) is mounted to a position offset (23) as viewed in the direction orthogonal to the center of an optical axis (14) of backward light (13) of an LD (11) in such a manner that a light receiving plane (21) thereof becomes substantially parallel to the center of the optical axis. Alternatively, the PD (20) is mounted thereto so that the light receiving plane of the PD is inclined at angles ranging from about 0° to about 30° to the center of the optical axis of the backward light. Further, the PD whose side face on the LD side is inclined, is used to repeatedly reflect the backward light between the PD and an LD mounting substrate, after which the backward light is launched on the light receiving plane 21.

Abstract: A ceramic substrate is provided through a stem of a can-package, the desired number of wirings including the high speed signal wirings are formed on this ceramic substrate and the necessary electronic components other than a light-emitting/photosensitive element such as driver LSI and amplifying LSI or the like are also accommodated within the can-package.

Abstract: The printed circuit board with the respective components of the optical transmitter-receiver mounted thereon is split into several parts, the fixing position of which respective parts with regard to the housing is set according to the standardized size of the respective components and which respective parts are interconnected through an electric connector and so forth, which makes the height of the transmitter-receiver lower. The split circuit boards are overlapped such that they make no contact with one another so as to enlarge the area of the circuit boards or practically increase the packaging area of the respective components, which realizes the structural compactness of the optical transmitter-receiver. The packaging side of the respective components is selected in an arbitrary manner according to the cooling direction of the respective ICs, which allows such direction to be oriented to the side of the heat sinks so as to enhance cooling behavior.

Abstract: The incident angle of the beam with regard to an etalon is arranged finely tunable by either rotating the etalon provided with a plane of incidence inclined with regard to the rotational axis thereof in the vicinity of the optical axis or rotating a lens whose edge surface is obliquely ground around the optical axis, which allows the incident angle of the laser beam with regard to the etalon to be adjusted and fixed with high precision.

Abstract: Reducing a dark current in a semiconductor photodetector provided with a second mesa including an regrown layer around a first mesa. An n-type buffer layer, a n-type multiplication layer, a p-type field control layer, a p-type absorption layer, a cap layer made of p-type InAlAs crystal, and a p-type contact layer 107 are made to grow on a main surface of a n-type substrate. Thereafter the p-type contact layer, the p-type cap layer, the p-type absorption layer and the p-type field control layer are patterned to form a first mesa. Next, after making a p-type regrown layer selectively grow around the first mesa or by forming a groove in the regrow layer located in a vicinity of the p-type cap type during a step of the selective growth, the p-type cap layer containing Al and the regrow layer are separated owing to the groove such that no current path is formed between both layers.

Abstract: In a directly modulated optical module, the input current to drive the semiconductor laser is controlled so as to make a rate of change in fall time smaller than a rate of change in rise time (inclination) in order to improve the eye opening of an eye pattern and extend the transmission distance. In addition, the input current is overshot at least during the period of transient state following the rising edge.

Abstract: The present invention provides an optical transmission module comprising: a laser diode; a lens for condensing a laser beam from the laser diode; a fiber ferrule which is placed so that the laser beam condensed by the lens can enter a fiber core; and a lens aperture or a lens aperture portion which is provided at one of the lens itself, a position before the lens and a position after the lens.