Abstract: In a moving-object power supply system, a control unit selects, as a power transmission segment, one of segments included in at least one power transmission section. The control unit supplies, through a power supply circuit, power to the power transmission segment to thereby generate a magnetic field through a power transmission coil of the power transmission segment. The control unit determines, based on an ascertained first electrical characteristic of the power transmission segment and an ascertained second electrical characteristic of at least one power non-transmission segment, whether there is a malfunction in each of the power transmission segment and the at least one power non-transmission segment.

Abstract: Provided is an electro-absorption modulator that includes a substrate, a mesa structure, a first conductivity type electrode, and a second conductivity type electrode. The first conductivity type electrode includes a mesa-top electrode, a pad electrode, and a lead-out wire electrode. The mesa structure has a light input end, to which light is to be input from outside, and a light output end, which is on a side of the mesa structure that is opposite of the light input end. A connection position between a center position in a short-side direction of the lead-out wire electrode and the mesa-top electrode is closer to the light output end side in a long-side direction of the mesa-top electrode. The connection position is a position that is less than 50% from the light output end side with respect to a length in the long-side direction of the mesa-top electrode.

Abstract: To provide an optical semiconductor device having excellent long-term reliability, the optical semiconductor device includes: a substrate; a mesa structure provided on the substrate; a semiconductor burial layer provided in contact with two sides of the mesa structure; and an electrode containing Au, which is provided above the semiconductor burial layer. The mesa structure includes a first conductivity type semiconductor layer, a multiple-quantum well layer, and a second conductivity type semiconductor layer, which are stacked in the stated order from a substrate side. The semiconductor burial layer includes a first semi-insulating InP layer provided in contact with side portions of the mesa structure, a first anti-diffusion layer provided in contact with the first semi-insulating InP layer, and a second semi-insulating InP layer provided on the first anti-diffusion layer. The first anti-diffusion layer has an Au diffusion constant that is smaller than that of the first semi-insulating InP layer.

Abstract: An optical semiconductor device includes a semiconductor substrate with a protrusion that forms a lower end portion of a mesa stripe structure in a stripe shape extending in a first direction; a multi-quantum well layer in a stripe shape extending in the first direction on the protrusion, wherein the multi-quantum well layer forms an intermediate portion of the mesa stripe structure; a semiconductor layer in a stripe shape extending in the first direction on the intermediate portion, wherein the semiconductor layer forms an upper end portion of the mesa stripe structure; and a semi-insulating semiconductor layer in contact with side surfaces of the mesa stripe structure on both sides in a second direction perpendicular to the first direction. The optical semiconductor device may include a first electrode on a surface of the semiconductor substrate and/or a second electrode on the upper end surface of the mesa stripe structure.

Abstract: An optical semiconductor device includes a semiconductor substrate; a plurality of mesa stripes, which are arranged side by side on the semiconductor substrate, and each of which includes an active layer and a diffraction grating, the diffraction grating extending up to a back end surface of each of the plurality of mesa stripes; a plurality of electrodes, each of which is electrically connected to an upper surface of a corresponding one of the plurality of mesa stripes, having a pad portion for wire bonding; a plurality of waveguides, each of which is optically connected to the active layer of a corresponding one of the plurality of mesa stripes; and a reflective film provided at back end surfaces of the plurality of mesa stripes and having a reflectivity of 30% or more, wherein a center-to-center distance at back end surfaces of two mesa stripes at both ends of the plurality of mesa stripes is 150 ?m or less, and wherein at least two mesa stripes, of the plurality of mesa stripes, are configured to be drive