A semiconductor device comprises a substrate and a plurality of emitters disposed on the substrate. The emitter may comprise: a first conductive reflection layer having a first reflectivity; an active layer disposed on the first conductive reflection layer; an aperture layer disposed on the active layer and comprising an aperture region and a blocking region surrounding the aperture region; and a second conductive reflection layer disposed on the aperture layer and having a second reflectivity smaller than the first reflectivity. A diameter-to-pitch ratio of the aperture region of the aperture layer is 1:3 to 1:5, wherein the pitch may be defined as the distance between centers of aperture regions of aperture layers of adjacent emitters.

A semiconductor device comprises a substrate and a plurality of emitters disposed on the substrate. The emitter may comprise: a first conductive reflection layer having a first reflectivity; an active layer disposed on the first conductive reflection layer; an aperture layer disposed on the active layer and comprising an aperture region and a blocking region surrounding the aperture region; and a second conductive reflection layer disposed on the aperture layer and having a second reflectivity smaller than the first reflectivity. A diameter-to-pitch ratio of the aperture region of the aperture layer is 1:3 to 1:5, wherein the pitch may be defined as the distance between centers of aperture regions of aperture layers of adjacent emitters.

A semiconductor laser drive circuit includes: an anode electrode divided into at least one gain region and at least one light absorption region; a cathode electrode shared between the gain region and the light absorption region; and a resistance connected to the anode electrode of the light absorption region.

Heatsinking in laser devices may be improved via a device, including: a header disk having a first face with a circumference; a header post that is thermally conductive, and having: a second face connected to the first face coterminously with the circumference; a third face opposite to the second face; and a fourth face perpendicular to the second face and the third face; a lens holder, having a fifth face connected to the third face; and an optical subassembly connected to the fourth face and optically aligned with the lens holder. The device may also be understood to comprise: a header disk having a circumference; a header post that is thermally conductive, the header post having: an arc coterminous to a portion of the circumference; a mounting face, perpendicular to a plane in which the arc and the circumference are defined; and a bonding face perpendicular to the mounting face.

A package for at least one laser diode includes: leads configured to be electrically connected to the at least one laser diode; a base including a mounting surface on which the at least one laser diode is to be mounted and a lateral wall located around the mounting surface so as to surround the at least one laser diode, the lateral wall defining first through-holes and including a light-transmissive part configured to transmit a laser beam emitted from the at least one laser diode; and a lead holding member bonded to the lateral wall of the base and defining second through-holes. The leads are disposed through the first through-holes and the second through-holes. At least a central portion of each of the leads is made of copper.

The optical device includes a magnetic element including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer, and a laser diode. At least a part of light emitted from the laser diode is applied to the magnetic element.

The optical device includes a magnetic element including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer, and a laser diode. At least a part of light emitted from the laser diode is applied to the magnetic element.

An optical module includes a circuit board having a through hole for the lead terminal, a signal wiring connected to the lead terminal, a ground layer providing a reference potential, an opening through which the ground layer is exposed, and a bonding material connecting the ground layer to the metallic base. The lead terminal extends in a first direction, and the circuit board and the signal wiring extend in a second direction. When the circuit board is viewed from the first direction, the opening overlaps with the signal wiring, or when the opening does not overlap with the signal wiring, a first distance between the signal wiring and a closest point of the opening to the signal wiring is smaller than a second distance between the closest point and an edge of the circuit board.

This optical transmission module includes: a plurality of semiconductor lasers provided on a sub-mount fixed to a side surface of a block fixed on a plate-shaped stem made of metal; and a cap with a lens fixed thereto, the cap covering all members placed above the stem. The same number of lead pins as the semiconductor lasers are provided so as to respectively penetrate through a plurality of holes formed in the stem. The lead pins and the semiconductor lasers are electrically connected to each other, respectively. Single-phase electrical signals with the stem as a ground potential are respectively applied to the semiconductor lasers from an external power supply, through the lead pins, respectively, so as to cause modulation and oscillation of the semiconductor lasers.

This optical transmission module includes: a plurality of semiconductor lasers provided on a sub-mount fixed to a side surface of a block fixed on a plate-shaped stem made of metal; and a cap with a lens fixed thereto, the cap covering all members placed above the stem. The same number of lead pins as the semiconductor lasers are provided so as to respectively penetrate through a plurality of holes formed in the stem. The lead pins and the semiconductor lasers are electrically connected to each other, respectively. Single-phase electrical signals with the stem as a ground potential are respectively applied to the semiconductor lasers from an external power supply, through the lead pins, respectively, so as to cause modulation and oscillation of the semiconductor lasers.