Abstract: Provided is a printed circuit board realizing selective inhibition of electromagnetic noise and enabling high-density arrangement of differential transmission lines without increasing cost. The printed circuit board includes a pair of strip conductors (first layer), a first resonance conductor plate, a ground conductive layer (together with a second layer) including an opening portion, a second resonance conductor plate (third layer), a third resonance conductor plate (fourth layer), first via holes connecting the first and second resonance conductor plates, a second via hole connecting the second and third resonance conductor plates, and third via holes connecting the third resonance conductor plate and the ground conductive layer, wherein a polygon obtained by sequentially connecting centers of the adjacent third via holes overlaps so as to include the first resonance conductor plate, and center-to-center distance between the adjacent third via holes is 0.

Abstract: Provided is a print circuit board including: a ground conductor layer; a pair of strip conductors extending along a first orientation; a first resonator conductor three-dimensionally intersecting with the pair of strip conductors along a second orientation; a pair of first via holes connecting the first resonator conductor and the ground conductor layer; and a dielectric layer including the first resonator conductor therein, and being disposed between the ground conductor layer and the pair of the strip conductors. A distance H1 between the pair of strip conductors and the ground conductor layer is twice or more a distance H2 between the pair of strip conductors and the first resonator conductor, and a line length L of the first resonator conductor is 0.4 wavelength or more and 0.6 wavelength or less at a frequency corresponding to the bit rate.

Abstract: A modulation doped semiconductor laser includes a multiple quantum well composed of a plurality of layers including a plurality of first layers and a plurality of second layers stacked alternately and including an acceptor and a donor; a p-type semiconductor layer in contact with an uppermost layer of the plurality of layers; and an n-type semiconductor layer in contact with a lowermost layer of the plurality of layers, the plurality of first layers including the acceptor so that a p-type carrier concentration is 10% or more and 150% or less of the p-type semiconductor layer, the plurality of second layers containing the acceptor so that the p-type carrier concentration is 10% or more and 150% or less of the p-type semiconductor layer, the plurality of second layers containing the donor, and an effective carrier concentration corresponding to a difference between the p-type carrier concentration and an n-type carrier concentration is 10% or less of the p-type carrier concentration of the plurality of second l

Abstract: A photoelectric conversion element includes a substrate including a lens-shaped convex portion and an annular concave portion surrounding the lens-shaped convex portion on a first main surface; a photoelectric conversion layer, positioned on an optical path of light passing through the lens-shaped convex portion, on a second main surface side of the substrate; and a pattern disposed on an outer peripheral side of the annular concave portion on the first main surface and disposed to interpose the lens-shaped convex portion from a first direction and a second direction intersecting the first direction.

Abstract: A semiconductor optical element is configured to emit or absorb light and includes a lower structure that includes a multiple quantum well layer; an upper mesa structure that is disposed on the lower structure; a current injection structure that is disposed on the upper mesa structure, when seen from an optical axis of the emitted or absorbed light, a width of a portion of the current injection structure in contact with the upper mesa structure is smaller than a width of the upper mesa structure, the portion of the current injection structure in contact with the upper mesa structure consisting of InP, and an average refractive index of the upper mesa structure is higher than a refractive index of the InP forming the current injection structure; and an insulating film covering both side surfaces of the upper mesa structure and a part of an upper surface of the upper mesa structure.

Abstract: An optical module includes at least one optical sub-assembly; at least one control circuit configured to control the at least one optical sub-assembly; and a housing including a first case and a second case, wherein the optical module is configured to be plugged in and unplugged from an optical transmission equipment including a heat sink provided at a joining portion with the first case, wherein, through fitting of the first case and the second case, the housing accommodates the at least one optical sub-assembly and the at least one control circuit inside the housing, and wherein a material of the first case has a thermal conductivity higher than a material of the second case.

Abstract: A printed circuit board includes a first transmission line provided on an insulating base, a first ground conductor, a notch portion that exposes a part of the first ground conductor, a conductor provided in the notch portion and electrically connected to the first ground conductor, and a first electrode exposed on a main surface of the insulating base facing a flexible board and electrically connected to the first transmission line. The flexible board includes a second transmission line provided on an insulating sheet, a second ground conductor, a second electrode exposed on a main surface of the insulating sheet facing the printed circuit board and connected to the second transmission line, and a third electrode exposed on the main surface of the insulating sheet and connected to the second ground conductor. The conductor and the third electrode are connected by solder.

Abstract: The upper surface of the semiconductor substrate has a slope descending from the projection in the second direction at an angle of 0-12° to a horizontal plane. The mesa stripe structure has an inclined surface with a slope ascending from the upper surface of the semiconductor substrate at an angle of 45-55° to the horizontal plane, the mesa stripe structure having an upright surface rising from the inclined surface at an angle of 85-95° to the horizontal plane. The buried layer is made from semiconductor with ruthenium doped therein and is in contact with the inclined surface and the upright surface. The inclined surface is as high as 80% or less of height from the upper surface of the semiconductor substrate to a lower surface of the quantum well layer and is as high as 0.3 ?m or more.

Abstract: A semiconductor light-receiving element includes a substrate; a light-receiving mesa portion, formed on top of the substrate, including a first semiconductor layer of a first conductivity type, an absorption layer, and a second semiconductor layer of a second conductivity type; a light-receiving portion electrode, formed above the light-receiving mesa portion, connected to the first semiconductor layer; a pad electrode formed on top of the substrate; and a bridge electrode, placed so that an insulating gap is interposed between the bridge electrode and the second semiconductor layer, configured to connect the light-receiving portion electrode and the pad electrode on top of the substrate, the bridge electrode being formed in a layer separate from layers of the light-receiving portion electrode and the pad electrode.

Abstract: An optical subassembly may include a plurality of optical semiconductor devices arrayed such that a plurality of light beams respectively traveling in parallel in a first direction are emitted therefrom or incident thereon. The optical subassembly may also include a carrier on which the plurality of optical semiconductor devices are mounted. Adjacent ones of the plurality of optical semiconductor devices may be located at positions shifted in a second direction orthogonal to the first direction and may be shifted in the first direction so as not to face each other in the second direction.

Abstract: An optical transmitter module includes optical semiconductor devices including a first optical semiconductor device, a temperature adjustment means for collectively performing temperature adjustment on the optical semiconductor devices, and a first thermal resistor that is disposed between the first optical semiconductor device and the temperature adjustment means, in which, when the temperature adjustment means is driven, the temperature of the first optical semiconductor device is higher than temperatures of other optical semiconductor devices which are different from the first optical semiconductor device.

Abstract: An optical device includes a first substrate, having first and second surfaces, and a second substrate having a third surface. The first substrate includes: a laser unit, having an active layer and emitting light into the first substrate from the active layer; a reflecting mirror, having a plane obliquely intersecting an optical axis of light emitted from the laser unit, and being formed on the first surface so as to reflect the light toward the second surface; and a convex lens, being formed in a region on the second surface, the region including an optical axis of the light reflected by the reflecting mirror. The second substrate is provided with a grating coupler and an optical waveguide on the third surface, the optical waveguide having light incident on the grating coupler propagating therethrough.

Abstract: The present invention provides a printed circuit board comprising: a dielectric layer (130); N pairs of differential signal vias (2) which penetrate through the dielectric layer wherein N is an integer more than one; N pairs of first strip conductors (101,102) disposed on a first surface of the dielectric layer; a first ground conductor layer (103) disposed in the dielectric layer forming N first differential transmission lines (100) with the N pairs of first strip conductors and the dielectric layer; N pairs of second strip conductors (111,112) disposed on a second surface of the dielectric layer; a second ground conductor layer (113) disposed in the dielectric layer forming N of second differential transmission lines (110) with the N pairs of second strip conductors and the dielectric layer.

Abstract: An optical receiver module includes: a lens array including a plurality of condenser lenses arranged in one direction to define a plane with optical axes in parallel to each other; and a light receiving element array including a plurality of light receiving elements each configured to receive light emitted from each of the condenser lenses. The light receiving element array includes: a semiconductor substrate to which the light from each of the condenser lenses is input and through which the light is transmitted; and light receiving portions each configured to receive the light transmitted through the semiconductor substrate and convert the light into an electrical signal. A shift of the optical axis of each of the condenser lenses from a center of each corresponding one of the light receiving portions is larger in a direction perpendicular to the one direction within the plane than in the one direction.

Abstract: Provided are a semiconductor photodiode which achieves a higher response rate in a state in which light receiving sensitivity is maintained. The semiconductor photodiode includes a p-type semiconductor contact layer, an n-type semiconductor contact layer, and a light absorption layer. The light absorption layer includes a first semiconductor absorption layer having a thickness Wd and a p-type second semiconductor absorption layer having a thickness Wp. The first semiconductor absorption layer and the second absorption layer are made of the same composition. The first semiconductor absorption layer is depleted, and the second semiconductor absorption layer maintains an electric charge neutral condition except for a region near an interface with the first semiconductor absorption layer. A relationship between the thickness Wd and the thickness Wp satisfies 0.47?Wp/(Wp+Wd)?0.9.

Abstract: A modulator integrated laser has a laser portion for emitting light and a modulation portion for modulating the light by an electric field absorption effect. The modulator integrated laser has a semiconductor substrate of a conductivity type in which the laser portion and the modulation portion are integrated. An impedance element with inductance and capacitance connected in parallel. The impedance element has a self-resonant characteristic exhibiting the highest impedance at a self-resonant frequency. The laser portion has first and second electrodes for a direct current voltage to be applied therebetween. The modulation portion has third and fourth electrodes for an alternate current voltage to be applied therebetween. The second electrode and the fourth electrode are electrically connected to each other through the semiconductor substrate. The impedance element is connected in series to the first electrode to minimize a flow of an alternate current.

Abstract: An optical module for transmitting an optical signal may include a circuit board on which electronic components are disposed, a high-frequency component that is disposed on a main surface of the circuit board and operates at a frequency equal to or higher than a predetermined reference value according to a frequency of the optical signal, a low-frequency component that is disposed on another main surface of the circuit board so as to overlap at least partly with the high-frequency component in a plan view and operates at a frequency less than the reference value, and an electromagnetic wave absorber that is disposed on an upper surface of the low-frequency component.

Abstract: An optical module includes a photoelectric converter configured to receive an optical signal having an intensity that changes at one of a first frequency or a second frequency that is higher than the first frequency, and convert the optical signal into a current signal corresponding to the intensity of the optical signal; a signal processor configured to acquire, when the optical signal has the intensity that changes at the first frequency, wavelength information set on a transmitting side based on a ratio between a plurality of signal intensities included in the current signal relating to the optical signal having the intensity that changes at the first frequency; and a decoder configured to generate, when the optical signal has the intensity that changes at the second frequency, communication data from the current signal relating to the optical signal having the intensity that changes at the second frequency.

Abstract: An electro-optic waveguide device may include a slot waveguide including a lower high-refractive-index layer with a first refractive index and an upper high-refractive-index layer with a second refractive index, wherein the lower high-refractive-index layer and the upper high-refractive-index layer have conductivity and are disposed to face each other with a gap; and a slot part formed as a low-refractive-index layer, wherein the low-refractive-index layer is formed of a material producing an electro-optic effect and has a third refractive index lower than the first refractive index and the second refractive index, wherein the low-refractive-index layer is formed in the gap to come into contact with the lower high-refractive-index layer and the upper high-refractive-index layer, and wherein one of the lower high-refractive-index layer or the upper high-refractive-index layer includes a stretch stretching on both sides of a contact portion with the slot part in a width direction intersecting a transmission dir

Abstract: Provided is a printed circuit board realizing selective inhibition of electromagnetic noise and enabling high-density arrangement of differential transmission lines without increasing cost. The printed circuit board includes a pair of strip conductors (first layer), a first resonance conductor plate, a ground conductive layer (together with a second layer) including an opening portion, a second resonance conductor plate (third layer), a third resonance conductor plate (fourth layer), first via holes connecting the first and second resonance conductor plates, a second via hole connecting the second and third resonance conductor plates, and third via holes connecting the third resonance conductor plate and the ground conductive layer, wherein a polygon obtained by sequentially connecting centers of the adjacent third via holes overlaps so as to include the first resonance conductor plate, and center-to-center distance between the adjacent third via holes is 0.