Abstract: A laser device includes: a laser unit that outputs laser light; an output end that launches the laser light; a first fusion splice portion; and a second fusion splice portion. In each of the first fusion splice portion and the second fusion splice portion, two multi-mode fibers are fusion-spliced. Each of the two multi-mode fibers include a core through which the laser light propagates and a cladding that surrounds the core. The first fusion splice portion is disposed closer to the laser unit than is the second fusion splice portion. At least a part of the core in the first fusion splice portion contains a dopant that is the same type as a dopant contained in the cladding in the first fusion splice portion for decreasing a refractive index.

Abstract: A laser device includes at least one light source; a delivery fiber configured to propagate laser light launched from the light source; a monitor fiber optically coupled to the delivery fiber and configured to propagate a part of the light propagating in a direction opposite to a propagation direction of the laser light in the delivery fiber, and a light receiving unit configured to receive the light propagated by the monitor fiber. The light receiving unit is configured to detect first light included in a wavelength band of visible light.

Abstract: A laser device includes at least one light source; a delivery fiber that is configured to propagate of laser light emitted from the light source; and a first light detection unit and a second light detection unit configured to detect a part of light propagating in a direction opposite to a propagation direction of the laser light through the delivery fiber. The first light detection unit detects first light included in a wavelength band of visible light. The second light detection unit detects second light included in a wavelength band of near-infrared light.

Abstract: A laser device includes: a laser unit that outputs laser light; an output end that launches the laser light; a first fusion splice portion; and a second fusion splice portion. In each of the first fusion splice portion and the second fusion splice portion, two multi-mode fibers are fusion-spliced. Each of the two multi-mode fibers include a core through which the laser light propagates and a cladding that surrounds the core. The first fusion splice portion is disposed closer to the laser unit than is the second fusion splice portion. At least a part of the core in the first fusion splice portion contains a dopant that is the same type as a dopant contained in the cladding in the first fusion splice portion for decreasing a refractive index.

Abstract: A coil wiring element includes: a plurality of first wirings that are formed above a substrate and have a center portion and both end portions; a second resin portion that is formed above the substrate and support both end portions of each of the first wirings; a first resin portion that covers the center portion of each of the first wirings; a plurality of second wirings that are formed above the first resin portion and have both end portions; connecting portions that connect the first wirings to the second wirings and are supported by the second resin portion; and a coil wiring in which both end portions of the first wirings are connected to both end portions of the second wirings in series, the coil wiring being wound around the first resin portion in a spiral shape.