Abstract: An optical connection structure includes a first ferrule, a second ferrule, and a split sleeve that has an insertion hole into which at least part of the first ferule and at least part of the second ferule are inserted, in which the split sleeve has a first end in which the first ferrule is inserted and a second end in which the second ferrule is inserted, and when assuming that a dimension of a first taper surface is x1, a distance between a first connection end surface and the first end is y1, a dimension of the second taper surface is x2, and a distance between a second connection end surface and the second end is y2, the following expressions a, b, and c are established.

Abstract: An optical receptacle includes: a first optical fiber; a second optical fiber connected to the first optical fiber by fusion splice; a ferrule including a fiber hole that holds an end of the first optical fiber; and a housing portion that houses therein: the ferrule, the first optical fiber, and a first portion of the second optical fiber. A fusion splice portion between the first optical fiber and the second optical fiber is disposed outside of the ferrule and within the housing portion.

Abstract: An optical receptacle includes: a first optical fiber; a second optical fiber connected to the first optical fiber by fusion splice; a ferrule including a fiber hole that holds an end of the first optical fiber; and a housing portion that houses therein: the ferrule, the first optical fiber, and a first portion of the second optical fiber. A fusion splice portion between the first optical fiber and the second optical fiber is disposed outside of the ferrule and within the housing portion.