Abstract: A sub-mount for fixing a photodiode is provided with an opening for transmitting an light, which is incident from below a light receiving portion of the photodiode. A wavelength selective filter having a wavelength selective function via a dielectric multilayer film is fixed to the opening for transmitting the incident light. Further, a light shading structure for shading scattering light incident from the side of the photodiode is provided and the whole light-receiving-portion-side surface is covered by potting with an opaque resin for absorbing scattering light incident from the light-receiving-portion-side surface of the photodiode, whereby an optical receiver excellent in wavelength selectivity is formed.

Abstract: An LD module having a spot-size conversion LD for emitting a beam of a small aperture angle, an optical fiber or a waveguide and a lens for converging the LD beam to the fiber or the waveguide.

Abstract: An optical waveguide-integrated substrate comprises a first optical waveguide on part of one side (referred to as the first side) of a substrate and a second optical waveguide on part of the other side (referred to as the second side) of the substrate. Both optical waveguides comprise a core and a cladding layer enclosing the core. A method for producing an optical waveguide-integrated substrate comprises preparing a substrate, forming a first optical waveguide on part of the first side of the substrate, and forming a second optical waveguide on part of the second side of the substrate at a temperature different from that for forming the first optical waveguide. An optical transceiver comprises the optical waveguide-integrated substrate, at least one optical-signal-transmitting device mounted on the remaining part of the first side of the substrate, and at least one optical-signal-receiving device mounted on the remaining part of the second side of the substrate.

Abstract: A device including a fiber/waveguide and a optical device (PD, LD or so). The end of an optical fiber or a light waveguide is cut slantingly. A transparent resin of a refractive index akin to the fiber/waveguide encloses the fiber/waveguide, the optical device and a space between them. The slanting end cutting and the transparent resin cooperate with each other to annihilate the reflection, returning light perfectly without reducing the coupling coefficient.

Abstract: A photodiode that is used in an optical communication system using two different wavelengths, &lgr;1 and &lgr;2(&lgr;1<&lgr;2), and that enables a reduction in the optical crosstalk caused by outgoing light having a longer wavelengths, &lgr;2. A photodiode that receives light having a shorter wavelengths, &lgr;1, is provided with an absorption layer made of a material having a bandgap wavelength, &lgr;g (&lgr;1<&lgr;g<&lgr;2), to detect the light having &lgr;1. A filter layer that absorbs unwanted light having &lgr;2 is provided over the absorption layer so that the light having &lgr;2 cannot return to the absorption layer after passing through it once.

Abstract: The optical module comprises a ferrule, an optical fiber inserted into the ferrule, an optical communication functional unit for making the optical communication with the optical fiber, and a resin molded portion covering a part of the ferrule and the optical communication functional unit. The ferrule is provided with one or more concave grooves in a region exposed from the resin molded portion. Since this concave portion serves as a resin reservoir at the time of molding, the resin is prevented from adhering and covering on the outer surface of ferrule exposing from the resin molded portion.

Abstract: A photodiode (A) comprises a substrate, a light receiving layer having a band gap wavelength and including a pn-junction and at least an absorption layer having a band gap wavelength &lgr;g. One of the absorption layers is sandwiched between the substrate and the light receiving layer, the band gap wavelength &lgr;g of the absorption layer is shorter than the receiving signal wavelength &lgr;2 but longer than noise wavelength &lgr;1(&lgr;1<&lgr;g<&lgr;2). Otherwise a photodiode (B) has two absorption layers epitaxially made on the substrate. One absorption layer is formed on the top surface of the substrate. The other absorption layer is formed on the bottom surface of the substrate. The absorption layers annihilate the noise &lgr;1. The PD has no sensitivity to &lgr;1.

Abstract: The invention reduces the costs of a surface mounting type receiver module, transmitter module, and transmitter and receiver module. In an optical communication device comprising an optical fiber, optical parts, and a substrate for optical coupling, the coupling portion between the end portion of the optical fiber and the optical parts is fixed by a semiconductor substrate having a V groove made by etching, and a portion of the optical fiber other than the end portion is fixed by a retaining substrate which is different from the semiconductor substrate.

Abstract: The optical communication module comprises a laminated lead frame composed of a plurality of lead frames that are laminated and held by a tie bar made of an insulating material, and an optical communication functional unit that is disposed on at least one layer of the lead frame. The optical communication functional unit comprises at least one of a light emitting element (LD) and a light receiving element and an optical transmission medium (optical fiber).

Abstract: An optical communication module includes (a) at least one light-emitting device, at least one light-receiving device, or a combination of these; (b) an optically coupling means coupled optically with the device or each device; (c) an electric-circuit part connected to the device or each device; (d) multiple layers of electroconductive media supporting the device or devices, the optically coupling means or these optically coupling means, and the electric-circuit part or parts; and (e) a connector portion formed at the end portion of each of the electroconductive media. The insertion of the next-stage circuit substrate between the connector portions enables the electrical connection between the module and the next-stage circuit substrate having a multitude of leads without requiring a large space. An insulating spacer placed between the layers of the electroconductive media secures the electrical and thermal insulation. The module has a property of high-speed response.

Abstract: The light-emitting device has a fiber stub part, a semiconductor optical amplifying device, a photodiode, and a bench as its main parts. The fiber stub part is composed of a ferrule and a grating fiber. The fiber stub part and the semiconductor optical amplifying device are mounted on the bench, and optically coupled together. An optical cavity is composed of the light-reflecting face of the semiconductor optical amplifying device and the diffraction grating of the grating fiber. The light-emitting device, which does not use a pigtail fiber, can be downsized and can provide laser light with a desired wavelength.

Abstract: The invention provides an inexpensive and small-sized light-receiving module having high performance, including a light receiving part consisting of a photodiode or a photodiode and an amplifier, and a mechanism for coupling an optical fiber end to the light receiving part; wherein the light receiving part is electrically shielded by a conductive member having openings to interrupt outside noise, and both the light receiving part and conductive member are shielded by a resin mold for integration.

Abstract: Besides the central pn-junction and the central electrode, a PD chip has a peripheral pn-junction and a peripheral electrode which do not appear on the sides. The ends of the peripheral pn-junction are covered with a protection layer for preventing self-shortcircuit. A reverse bias is applied to the peripheral electrode for making a wide depletion layer beneath the peripheral pn-junction. Extra carriers generated by peripherally-incidence rays are fully absorbed by the peripheral depletion layer and annihilated by the reverse bias.

Abstract: A submount including a transparent substrate and at least one wavelength selective absorption layer being piled upon the substrate and having a band gap wavelength &lgr;g1 which is shorter than the necessary light wavelength &lgr;2 but longer than the unnecessary light wavelength &lgr;1. The submount is inserted between a case (package, metallized pattern) and a bottom incidence PD for insulating the PD from the case and for admitting only the necessary light.

Abstract: The present invention relates to an optical module with a small size and improved mass-productivity. The optical module comprises a fiber stub including an optical fiber, a sleeve containing the fiber stub, and a semiconductor optical amplifying device. A Bragg fiber grating is formed in the optical fiber. The optical fiber is secured in the ferrule. The optical amplifying device and the grating form a laser cavity. Only a part of the hollow portion of the sleeve is filled with the fiber stub. One end face of the optical fiber is disposed at one end of the sleeve. The other end of the sleeve is hollow. The optical module acts as an optical receptacle. An optical plug can be inserted into the hollow end of the sleeve. This enables the laser light to be introduced into an external optical device.

Abstract: A producing method an optical module is carried out as shown below. First, an optical-communication functional portion is disposed on a lead frame where each lead is held by an insulating connection leads. A screening test for the optical communication functional portion is performed. A product selected through a screening test process is packaged. In the above-mentioned method, the connection leads which are electrically insulated with one another and the screening test is performed before packaging or encapsulating. Consequently, the waste accompanied by discarding the component elements of the optical module, which has caused an increase in the cost, can be eliminated. Further, an attempt to reduce the cost of products can also be made.

Abstract: A photodiode having a resin film painted upon an opening through which signal light goes in and a dielectric multilayered film piled upon the resin film for reflecting noise light.

Abstract: Besides the central pn-junction and the central electrode, a PD chip has a peripheral pn-junction and a peripheral electrode which do not appear on the sides. The ends of the peripheral pn-junction are covered with a protection layer for preventing self-shortcircuit. A reverse bias is applied to the peripheral electrode for making a wide depletion layer beneath the peripheral pn-junction. Extra carriers generated by peripherally-incidence rays are fully absorbed by the peripheral depletion layer and annihilated by the reverse bias.

Abstract: An optical communication device including optoelectronic (LD, PD, LD/PD) elements allocated to a top surface of a circuit board and electronic, electric elements (IC, R/C) allocated to a bottom surface and to the top surface of the circuit board.

Abstract: Besides the central pn-junction and the central electrode, a PD chip has a peripheral pn-junction and a peripheral electrode which do not appear on the sides. The ends of the peripheral pn-junction are covered with a protection layer for preventing self-shortcircuit. A reverse bias is applied to the peripheral electrode for making a wide depletion layer beneath the peripheral pn-junction. Extra carriers generated by peripherally-incidence rays are fully absorbed by the peripheral depletion layer and annihilated by the reverse bias.