Abstract: The object is to provide an optical module for optical transmission which has a double resin structure wherein a transparent resin and a fixing resin are combined, which is low in price, and is easily produced. A package with a inside-and-outside double structure comprising an inner container having barriers filled with a transparent resin and a hard outer container formed of a fixing resin. The inner container stores the highly fluid transparent resin and prevents it from flowing out. The outer container provides mechanical strength and airtightness.

Abstract: In a surface-mounted optical receiver module comprising a substrate, a photodiode serving as a light receiving device for converting an optical signal into an electrical signal, an optical waveguide serving as an optical transmission line for transmitting the optical signal to the photodiode, and an amplifier device for amplifying the electrical signals, the amplifier device is placed at a predetermined position on the upper surface of the optical waveguide element, which is on the same side as an optical waveguide (on the upstream side in the optical-signal transmitting direction) relative to the photodiode. This configuration eliminates the necessity of additionally securing a space to provide the amplifier device, whereby the size of the optical transmission module can be reduced, and this allows the optical receiver module to receive optical signals at high speed.

Abstract: An optical transceiver module comprises a submodule having a Y-branching optical transmission line formed on a flat platform such that a leading end is exposed at the front surface and having an LD chip and a PD chip disposed at first and second trailing ends of the optical waveguide. The submodule is secured to the front surface of a pole of a metal stem, and a condenser lens and an end of an optical fiber are secured relative to the stem by a metal package member so that the optical fiber and the leading end of an optical waveguide can be optically coupled by the condenser lens. Transmission light from the LD is focused by the lens and can be sent out to the optical fiber, and reception light that has propagated through the optical fiber can be received by the PD. Thus, the optical transceiver module whose submodule is accommodated in a metal package is superior in reliability, durability, and airtightness.

Abstract: An optical communication module having a roughened bottom of a silicon bench for suppressing optical crosstalk. The roughened bottom prevents stray laser beams from reflecting toward a photodiode. The roughened bottom is further covered with a photoabsorbent resin, pigment or adhesive for absorbing the stray laser beams at a bottom. A cladding of a lightwaveguide are narrowed and are painted with a photoabsorbent resin, pigment or adhesive for absorbing horizontally stray beams propagating in the cladding.

Abstract: An inspection apparatus for an optical transmission device comprises a coupling means to be optically coupled to an optical transmission device, a selecting means for optically separating and selecting an optical signal of a specific wavelength from a plurality of optical signals having different wavelengths transmitted from the optical transmission device, a converting means for converting the selected optical signal into an electrical signal, and a displaying means for displaying the selected wavelength according to the electrical signal. The wavelength of a transmission signal from the optical transmission device can be easily and visually checked by selecting a signal of a specific wavelength out of a plurality of signals having different wavelengths transmitted from the transmission device, and by displaying the selected wavelength by the displaying means.

Abstract: 250 &mgr;m is the standardized pitch H of the prevalent multichannel ribbonfibers. Current laser diodes and photodiodes have a size larger than 300 &mgr;m. Curving lightpaths made on a silicon bench for reconciling the chip size with current ribbonfibers causes bending power loss, optical crosstalk and difficulty of production. Linear parallel lightpaths with a width d for more than one chip site are produced on a bench with a pitch E which is equal to the pitch H of the multichannels. Optoelectronic device chips with a width W satisfying an inequality E<W<2E−d are mounted on the lightpaths at spots which are different from neighboring chips in the longitudinal direction.

Abstract: An optical communication module, such as an optical transmitter used for optical communication incorporating a semiconductor laser (LD) and a monitoring photodiode (MPD), and an optical transceiver including a photodiode (PD), is efficiently and inexpensively provided. As means therefor, two substrates are used, that is, an expensive and high-accuracy first substrate is accommodated in an recess provided in a second substrate that is inexpensive and that needs less accuracy. An optical transmission system is mounted on the first substrate, and the MPD is mounted on the second substrate having an inclined surface provided on an opposite side of the recess in terms of the optical transmission direction. This eases production work and simultaneously allows the decreaseed use of expensive substrates.

Abstract: A transmitting and receiving module helps reduce electrical crosstalk and noise during transmitting and/or receiving signals. Electrical isolation among metallized electrodes in a surface-mounted module with an optical fiber and an optical device can be achieved by using a low resistivity Si substrate, providing ground terminals on the surface of the Si substrate, and grounding the Si substrate. Noise and crosstalk during transmitting and receiving signals can be reduced by providing a copper contact adhered to the bottom surface of the Si substrate and by grounding.

Abstract: An optical transmission module includes plural optical transmission means (optical waveguides) whose end portions are exposed on a first end face thereof, and at least one of an optical transmitting section and an optical receiving section to each of which some of the optical transmission means are optically coupled. The remaining optical transmission means are exposed on a second end face opposed to the first end face. Only some of the plural optical transmission means are designed to have a communication facility at some position in the longitudinal direction thereof, while the remaining optical transmission means are designed to have the communication facility by being connected to post-stage optical transmission modules in the longitudinal direction. By multistage-connecting these optical transmission modules, plural optical transmission means and optical transmission modules can be collectively connected at a narrow frontage.

Abstract: The invention relates to a wavelength-multiplexing connector enabling a conventional duplex-fiber transceiver to be easily adapted for use in a single-fiber duplex communication system, and also to an optical transmission device and an optical communication system, that employ the wavelength-multiplexing connector, respectively. A wavelength-multiplexing connector and a transmitting/receiving part can be easily connected to and disconnected from each other. The wavelength-multiplexing connector comprises a single optical fiber, through which a plurality of optical signals having different wavelengths are transmitted, and a wavelength-multiplexer optically coupled to the optical fiber and capable of optically separating an optical signal having a particular wavelength out of the plurality of optical signals.

Abstract: Disclosed is a photodiode array which includes a plurality of p-i-n photodiodes arrayed on a semi-insulative semiconductor substrate, each photodiode including an n-type semiconductor layer grown on the substrate, an i-type semiconductor layer grown on the n-type semiconductor layer, a p-type semiconductor layer grown on the i-type semiconductor layer, an n-type electrode provided on the n-type semiconductor layer in a region exposed by partially removing the p-type semiconductor layer and the i-type semiconductor layer, and a p-type electrode provided on the p-type semiconductor layer. A trench is provided between the two adjacent photodiodes by partially removing the p-type semiconductor layer, the i-type semiconductor layer, and the n-type semiconductor layer. Consequently, the size and pitch of the photodiodes can be decreased and crosstalk between the photodiodes can be reduced. Also disclosed is an optical receiver device including the photodiode array.

Abstract: A parallel multichannel LD/PD module comprising a bench, a set of M (M; channel number) curving lightpaths (lightwaveguides or optical fibers) having a narrow width region, a width enlarging region and a wide width region which are formed upon the bench, a wavelength selective filter provided at the wide width region for reflecting receiving beams upward, a set of photodiodes installed in front of the wavelength selective filter at the wide width region above the bench and light emitting devices mounted behind the ends of the lightpaths with a wide pitch for yielding transmitting beams. Propagating in outer M-channel element fibers of a ribbonfiber, receiving signal beams go into the lightpaths via the narrow width region, expand horizontally in the width enlarging region, arrive at the wide width region, and are reflected by the wavelength selective filter upward. The receiving beams go into the photodiodes which yield photocurrents in proportion to the powers of the receiving beams.

Abstract: In a surface-mounted optical transmission module, a laser diode serving as a light emitting device that converts an electric signal into an optical signal, and an optical waveguide serving as an optical transmission line that transmits and outputs the optical signal from the laser diode are placed on a substrate. A driving device for controlling the driving of the laser diode is placed at a predetermined position on the upper surface of the optical waveguide element, which is on the same side as an optical waveguide element (on the downstream side in the optical-signal transmitting direction) relative to the laser diode. This configuration eliminates the necessity of placing the driving device at a position distanced from the laser diode, whereby the size of the optical transmission module can be reduced, and this allows the optical transmission module to transmit optical signals at high speed.

Abstract: A multichannel parallel LD/PD module comprising a bench, a plurality of lightpaths having an initial narrow width region, an intermediate width enlarging region and a final wide width region, a plurality of photodiodes or a photodiode array mounted on the narrow width region, a wavelength selective filter formed on the narrow width region for selectively reflecting receiving beams, a plurality of light emitting devices fitted behind rear ends of the lightpaths on the bench. Traveling in element fibers in an outer ribbon fiber, receiving signal beams go into the lightpaths via front ends and are reflected by the wavelength selective filter slantingly upward at the narrow width region. The reflected beams go into the photodiodes and are converted into photocurrents in proportion to the receiving signals.

Abstract: An LD/PD module having a main silicon substrate having a cavity, a transmitting portion having an LD and an LD driving IC which is directly mounted upon the main silicon substrate, and a receiving portion having a PD and an amplifier which is indirectly mounted upon the main silicon substrate via an auxiliary insulating substrate embedded in the cavity. The auxiliary insulating substrate suppresses current-induced crosstalk from the transmitting portion to the receiving portion.

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 mate 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: 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: An LD module comprising a substrate, an LD, an LD driving IC and a monitoring PD mounted in this order on the substrate, wirings for connecting the LD to the IC, and a light guiding device provided below the IC for guiding the LD light to the monitoring PD by detouring the LD light beneath the LD driving IC.

Abstract: In an optical transmitter in which the amount of light of an LD is monitored by a monitor PD, and the power of the LD is kept constant by feedback, the present invention aims to provide an optical transmitter that is suitable for size and cost reductions while being able to input a greater amount of the LD light of to the monitor PD, and that is capable of performing higher-bit-rate transmission. The present invention is characterized in that a concave groove is formed in a substrate, and the monitor photodiode is mounted on a slanted face of the concave groove, and the light of the LD that is oppositely and horizontally disposed is received directly by the monitor the LD photodiode.

Abstract: An optical communication device (an LD module or an LD/PD module) having a flat substrate, a light waveguide layer formed upon the substrate with a core for guiding signal LD light, an LD bonded upon a part of the substrate without the whole or a part of the light waveguide layer for producing signal front light and monitoring rear light, a path conversion groove being perforated along the core on the substrate behind the LD and having slanting walls for reflecting rear light emitted backward from the LD, a bottom- or top-incidence type PD bonded upon the light waveguide layer over the path conversion groove for monitoring the LD power by detecting the LD rear light reflected by the path conversion groove. Since the PD level is higher than the LD by the thickness of the light waveguide layer, the monitoring PD can sense more than 50% of the LD rear light.