Optical receptacle and optical module

An optical receptacle configured to optically couple a light emitting element and an end surface of an optical transmission member when the optical receptacle is disposed between an optical transmission member and a photoelectric conversion device including the light emitting element and a detection element configured to monitor emission light emitted from the light emitting element, the optical receptacle comprising:

• a first optical surface configured to allow incidence of the light emitted from the light emitting element;
• a first transmission part configured to allow, to pass through the first transmission part as signal light travelling toward the end surface of the optical transmission member, a part of light entered from the first optical surface;
• a light separation part configured to separate another part of the light entered from the first optical surface into monitor light travelling toward the detection element and the signal light travelling toward the end surface of the optical transmission member;
• a second optical surface configured to emit, toward the end surface of the optical transmission member, the signal light passed through the first transmission part and the signal light separated by the light separation part;
• and
• a third optical surface configured to emit, toward the detection element, the monitor light separated by the light separation part,
• wherein the light separation part includes
• a reflection part inclined with respect to a light axis of the light entered from the first optical surface, the reflection part being configured to reflect, toward the third optical surface as the monitor light, a part of light incident on the light separation part,
• a plurality of second transmission parts disposed between the reflection part and the first transmission part, the plurality of second transmission parts being configured to allow, to pass through the plurality of second transmission parts as signal light, another part of the light incident on the light separation part, and
• the first transmission part and two or more second transmission parts of the plurality of second transmission parts are located within an optical effective region that is a region around a central axis, the central axis being set as a light axis of light that is entered from the first optical surface and is emitted from the second optical surface, the optical effective region having a periphery that is a surface separated from the central axis by a distance equal to one of a radius of the first optical surface and a radius of the second optical surface, the one of the radius of the first optical surface and the radius of the second optical surface being larger than the other.