A light detecting element is realized in which a length thereof is reduced in a direction perpendicular to a direction in which light detecting regions are disposed side by side. A light detecting element includes a light detecting surface provided with a plurality of light detecting regions disposed side by side in a first direction and a plurality of wiring regions electrically connected to the plurality of light detecting regions. Of the plurality of wiring regions, a plurality of the wiring regions connected to a plurality of the light detecting regions are provided in an end region that is a region excluding a central region at the light detecting surface.

A light detecting element is realized in which a length thereof is reduced in a direction perpendicular to a direction in which light detecting regions are disposed side by side. A light detecting element includes a light detecting surface provided with a plurality of light detecting regions disposed side by side in a first direction and a plurality of wiring regions electrically connected to the plurality of light detecting regions. Of the plurality of wiring regions, a plurality of the wiring regions connected to a plurality of the light detecting regions are provided in an end region that is a region excluding a central region at the light detecting surface.

A submount includes a light emitting device mounted thereon. The submount includes: a base including a first surface extending in a first direction and in a second direction that is orthogonal to the first direction; a first electrode extending in the first direction and in the second direction on the first surface, the first electrode including a first end in the second direction, and a second end in opposite direction of the second direction, the second end extending in the first direction; and a second electrode extending in the first direction and in the second direction on the first surface, the second electrode including a third end in the opposite direction of the second direction, the third end being separated from the first end in the second direction with a gap therebetween, and a fourth end in the second direction, the fourth end extending in the first direction. In the second electrode, a second width between the third end and the fourth end in the second direction differs according to a position in the first direction.

A lead pin (2a,2b) penetrates a metal stem (1). A support block (3) is mounted on the metal stem (1). A dielectric substrate (4) is mounted on a side surface of the support block (3). A signal line (5a,5b) is formed on the dielectric substrate (4). One end of the signal line (5a,5b) is connected to the lead pin (2a,2b). A semiconductor optical modulation device (6) is mounted on the dielectric substrate (4). A conductive wire (8a,8b) connects the other end of the signal line (5a,5b) and the semiconductor optical modulation device (6). The semiconductor optical modulation device (6) includes a plurality of optical modulators (6b,6c) separated from each other.

A lead pin (2a,2b) penetrates a metal stem (1). A support block (3) is mounted on the metal stem (1). A dielectric substrate (4) is mounted on a side surface of the support block (3). A signal line (5a,5b) is formed on the dielectric substrate (4). One end of the signal line (5a,5b) is connected to the lead pin (2a,2b). A semiconductor optical modulation device (6) is mounted on the dielectric substrate (4). A conductive wire (8a,8b) connects the other end of the signal line (5a,5b) and the semiconductor optical modulation device (6). The semiconductor optical modulation device (6) includes a plurality of optical modulators (6b,6c) separated from each other.

First block (10) and second block (20) are placed on top of each other with insulation sheet (45) interposed therebetween. First adherend surface (12) and second adherend surface (22) are provided on a facing surface of first block (10) and a facing surface of second block (20), respectively. Adhesive (50) is applied to first adherend surface (12) and second adherend surface (22). First block (10) and second block (20) are bonded to each other with adhesive (50).

A semiconductor laser machine includes a semiconductor laser element including a first end face that emits a laser beam and a second end face that is opposite the first end face; a heat sink; and a sub-mount securing the semiconductor laser element to the heat sink. The sub-mount includes a substrate that serves as a thermal stress reliever, a solder layer joined to the semiconductor laser element, and a junction layer formed between the substrate and the solder layer. Compared with the semiconductor laser element, the substrate is extended in a rearward direction that is from the first end face toward the second end face. As for the solder layer and the junction layer, a portion of at least the solder layer is removed behind the second end face.

A light-emitting device includes: a base including: a mount surface, and a lateral wall located around the mount surface, the lateral wall including: a pair of first protrusions located opposite to each other in a first direction which is parallel to a side of the mount surface, and a pair of second protrusions located opposite to each other in a second direction which is perpendicular to the first direction, the second protrusions being provided lower than the first protrusions; one or more light-emitting elements mounted on the mount surface of the base; a first light-transmissive member sealing a space in which the one or more light-emitting elements are mounted; and one or more wires connecting to the one or more light-emitting elements, the one or more wires being bonded on conduction regions provided on at least one of upper surfaces of the second protrusions.

A light-emitting device includes: a base including: a mount surface, and a lateral wall located around the mount surface, the lateral wall including: a pair of first protrusions located opposite to each other in a first direction which is parallel to a side of the mount surface, and a pair of second protrusions located opposite to each other in a second direction which is perpendicular to the first direction, the second protrusions being provided lower than the first protrusions; one or more light-emitting elements mounted on the mount surface of the base; a first light-transmissive member sealing a space in which the one or more light-emitting elements are mounted; and one or more wires connecting to the one or more light-emitting elements, the one or more wires being bonded on conduction regions provided on at least one of upper surfaces of the second protrusions.

A chip package structure includes a substrate having a first surface and a second surface being opposite surfaces of the substrate; a housing disposed on the first surface of the substrate and enclosing a chip region; and a chip set disposed in the chip region and electrically connected to the substrate. The chip set includes a first chip and a second chip, and an active surface of the second chip faces the active surface of the first chip.