Abstract: A package for an optical module includes a substrate provided through a side wall in a first direction. The substrate includes a first wiring layer including a first signal terminal, a second signal terminal, and a first ground terminal. The package includes a second wiring layer disposed under the first wiring layer. The second wiring layer includes a first ground pattern and a first insulating layer disposed between the first wiring layer and the second wiring layer, and includes a groove extending along the first direction, the groove being filled with a metal. The groove is provided within the first ground terminal, in a plan view, and the first insulating layer is free of the groove. The first ground terminal is electrically coupled to the first ground pattern through the metal of the groove.

Abstract: A package for an optical module includes a substrate that includes a first wiring layer, a second wiring layer, and a third wiring layer. The package includes a first insulating layer between the first wiring layer and the second wiring layer, the first insulating layer including first vias. The package includes a second insulating layer between the second wiring layer and the third wiring layer, the second insulating layer including second vias and third vias. Each first vias is provided between a corresponding second via and a corresponding third via. The first vias are arranged at a first interval along a first direction. The second vias are arranged at a second interval along the first direction. Each second vias is disposed at an offset by half of the second interval from the corresponding third via.

Abstract: A printed board includes a first wiring layer including a first terminal, a second wiring layer including a second terminal facing to the first terminal, a dielectric layer interposed between the first wiring layer and the second wiring layer and having an end face, and a plurality of through-hole vias configured to electrically connect the first terminal and the second terminal. The plurality of through-hole vias includes a first through-hole via which is closest to an end-face edge of the first terminal, and a second through-hole via which is closest to an inner edge of the second terminal. The end-face edge being closer to the end face than the inner edge. A distance between the first through-hole via and the end-face edge is equal to or smaller than one eighth of a signal wavelength of a high speed signal transmitted through the first terminal.

Abstract: An amplifier circuit includes a first cascode transistor and a second cascade transistor, the first cascade transistor being electrically connected between a first transistor and a first load circuit, the second cascode transistor being electrically connected between a second transistor and a second load circuit. The amplifier circuit includes a first shunt transistor and a second shunt transistor, the first shunt transistor being electrically connected between the first transistor and a first emitter-follower circuit, the second shunt transistor being electrically connected between the second transistor and a second emitter-follower circuit. A differential current signal includes a first differential current and a second differential current, the first differential current flowing through the first cascode transistor and the second cascode transistor, and a second differential current flowing through the first shunt transistor and the second shunt transistor.

Abstract: According to one embodiment, an optical module includes: a lid having a first face and a second face, the lid including a bump, a wiring, and a through via; an optical circuit element; a first integrated circuit (IC); a first block bonded to the first IC by a first adhesive; a temperature control element bonded to the optical circuit element; and a housing having an opening and a third face provided inside the opening, the housing being configured to house the first IC, the optical circuit element, the first block, and the temperature control element, the third face being bonded to the first block and the temperature control element by a second adhesive, the housing being hermetically sealed with the lid.

Abstract: An optical module includes: a housing having a first face and a second face parallel to the first face; a first block fixed to the first face of the housing by a first adhesive; an integrated circuit (IC) fixed to the first block by a second adhesive having a thickness larger than a thickness of the first adhesive; a thermoelectric cooler (TEC) fixed to the second face of the housing; an optical circuit element fixed to the TEC; and an interconnection board mounted on the IC and the optical circuit element, the interconnection board being configured to electrically couple the IC to the optical circuit element. The first block is sandwiched between the housing and the IC. The TEC is sandwiched between the housing and the optical circuit element.

Abstract: A printed board includes a first wiring layer including a first terminal, a second wiring layer including a second terminal facing to the first terminal, a dielectric layer interposed between the first wiring layer and the second wiring layer and having an end face, and a plurality of through-hole vias configured to electrically connect the first terminal and the second terminal. The plurality of through-hole vias includes a first through-hole via which is closest to an end-face edge of the first terminal, and a second through-hole via which is closest to an inner edge of the second terminal. The end-face edge being closer to the end face than the inner edge. A distance between the first through-hole via and the end-face edge is equal to or smaller than one eighth of a signal wavelength of a high speed signal transmitted through the first terminal.

Abstract: An optical semiconductor device includes an insulative base having first and second surfaces, and a metallic pattern formed on the first surface and including a grounding pattern, a transmission pattern having a line connected between input and output ends thereof, and first and second patterns, where the first pattern is located between the second surface crossing a direction parallel to the first surface, and the second pattern. The device includes a laser chip, mounted on the first surface between the transmission pattern and the first and second patterns, and having an electrode and a light emitting end located between the electrode and the second surface, a first wire connecting the output end to the electrode, a second wire connecting the electrode to the first pattern, an inductor provided on the first surface connected between the first and second patterns and formed by a meander wiring or a bonding wire.

Abstract: An optical semiconductor device comprises: a first wiring pattern provided on a carrier mounting surface of a dielectric substrate; a first reference potential pattern surrounding the first wiring pattern; a carrier block provided on the carrier mounting surface and having a main surface, a side surface, and a second wiring pattern and a second reference potential pattern constituting coplanar lines; and an optical semiconductor element provided on the main surface. One end portion of the second wiring pattern extends to at least an end edge on the side surface side in the main surface and is conductively joined to the first wiring pattern with a conductive joining material therebetween. One end portion of the second reference potential pattern extends to at least the end edge on the side surface side in the main surface and is conductively joined to the first reference potential pattern with a conductive joining material therebetween.

Abstract: The optical module includes: a housing having first and second end walls and a pair of side walls; a semiconductor laser element; a first TEC; a wavelength locker unit including an optical splitting component and an etalon filter; and a second TEC. The second end wall is provided with a feedthrough. The pair of side walls is not provided with an external connection terminal. The second TEC is disposed between the first TEC and the second end wall and has: a first substrate thermally coupled to a bottom surface of the housing; a second substrate thermally coupled to the etalon filter; and a heat transfer part that transfers heat. The optical module further includes a wiring pattern that is arranged side by side with the heat transfer part and that supplies electric power to the first TEC from the feedthrough.

Abstract: An optical semiconductor device includes an insulative base having first and second surfaces, and a metallic pattern formed on the first surface and including a grounding pattern, a transmission pattern having a line connected between input and output ends thereof, and first and second patterns, where the first pattern is located between the second surface crossing a direction parallel to the first surface, and the second pattern. The device includes a laser chip, mounted on the first surface between the transmission pattern and the first and second patterns, and having an electrode and a light emitting end located between the electrode and the second surface, a first wire connecting the output end to the electrode, a second wire connecting the electrode to the first pattern, an inductor provided on the first surface connected between the first and second patterns and formed by a meander wiring or a bonding wire.

Abstract: An optical semiconductor device comprises: a first wiring pattern provided on a carrier mounting surface of a dielectric substrate; a first reference potential pattern surrounding the first wiring pattern; a carrier block provided on the carrier mounting surface and having a main surface, a side surface, and a second wiring pattern and a second reference potential pattern constituting coplanar lines; and an optical semiconductor element provided on the main surface. One end portion of the second wiring pattern extends to at least an end edge on the side surface side in the main surface and is conductively joined to the first wiring pattern with a conductive joining material therebetween. One end portion of the second reference potential pattern extends to at least the end edge on the side surface side in the main surface and is conductively joined to the first reference potential pattern with a conductive joining material therebetween.

Abstract: An optical module including a source assembly is disclosed. The source assembly provides a semiconductor optical device, a wiring substrate, and a bridge substrate. The semiconductor optical device includes an electrode and a pad that receives a driving signal therethrough. The wiring substrate, which is arranged side by side with respect to the semiconductor optical device, provides a signal line and a ground line surrounding the signal line. The bridge substrate includes a signal line and a ground line surrounding the signal line. A feature of the optical module is that the bridge substrate is placed on the semiconductor optical device and the wiring substrate such that a transmission line thereof faces the semiconductor optical device and the wiring substrate, and one end of the signal line thereof is connected with the pad of the semiconductor optical device through a post, and another end of the signal line thereof is connected with an end of the signal line in the wiring substrate through another post.

Abstract: The optical module includes: a housing having first and second end walls and a pair of side walls; a semiconductor laser element; a first TEC; a wavelength locker unit including an optical splitting component and an etalon filter; and a second TEC. The second end wall is provided with a feedthrough. The pair of side walls is not provided with an external connection terminal. The second TEC is disposed between the first TEC and the second end wall and has: a first substrate thermally coupled to a bottom surface of the housing; a second substrate thermally coupled to the etalon filter; and a heat transfer part that transfers heat. The optical module further includes a wiring pattern that is arranged side by side with the heat transfer part and that supplies electric power to the first TEC from the feedthrough.

Abstract: An optical module that includes at least one semiconductor optical device, a carrier, a housing, and eutectic alloy that fixes the carrier to the housing is disclosed. The carrier mounts a component that couples with the semiconductor optical device. The housing, which includes a side wall made of ceramics and a base made of metal to form a space that encloses the semiconductor optical device, the carrier, and the component therein. The carrier provides a room facing the base and the side wall, where the room receives excess eutectic alloy oozing out from a gap between the carrier and the base.

Abstract: A flexible printed circuit board includes: a board having a top surface and a back surface; a signal line on the top surface; a ground line on the back surface and overlapping with the signal line; a first signal terminal extending along a first direction in the top surface, the first signal terminal including a first via-hole and electrically connected with the signal line; a first ground terminal next to the first signal terminal along a second direction intersecting the first direction on the top surface, the first ground terminal including a second via-hole electrically connected with the ground line; and a second ground terminal next to the first signal terminal in a side opposite to the first ground terminal along the second direction on the top surface, the second ground terminal including a third via-hole electrically connected with the ground line.

Abstract: An optical module including a source assembly is disclosed. The source assembly provides a semiconductor optical device, a wiring substrate, and a bridge substrate. The semiconductor optical device includes an electrode and a pad that receives a driving signal therethrough. The wiring substrate, which is arranged side by side with respect to the semiconductor optical device, provides a signal line and a ground line surrounding the signal line. The bridge substrate includes a signal line and a ground line surrounding the signal line. A feature of the optical module is that the bridge substrate is placed on the semiconductor optical device and the wiring substrate such that a transmission line thereof faces the semiconductor optical device and the wiring substrate, and one end of the signal line thereof is connected with the pad of the semiconductor optical device through a post, and another end of the signal line thereof is connected with an end of the signal line in the wiring substrate through another post.

Abstract: An optical module that includes at least one semiconductor optical device, a carrier, a housing, and eutectic alloy that fixes the carrier to the housing is disclosed. The carrier mounts a component that couples with the semiconductor optical device. The housing, which includes a side wall made of ceramics and a base made of metal to form a space that encloses the semiconductor optical device, the carrier, and the component therein. The carrier provides a room facing the base and the side wall, where the room receives excess eutectic alloy oozing out from a gap between the carrier and the base.