Abstract: 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.

Abstract: An optical processing structure of an optical fiber, includes: an optical fiber that includes a core, a cladding, and a coating, the coating being partially removed; and a thermally conductive protective material made of a silicone-based thermally conductive compound and provided around the cladding in a coating removed region of the optical fiber. Further, the thermally conductive protective material contains a filler having a refractive index higher than a refractive index of the cladding, and the filler is present in a region where evanescent light seeping out of the cladding is present when cladding mode light propagating in the cladding is totally reflected.