OPTICAL BRANCHING/COUPLING DEVICE AND OPTICAL TRANSMISSION/RECEPTION MODULE

Provided is an optical branching/coupling device in which optical transmission quality is improved by preventing a reduction in optical transmission quality, the reduction being due, for example, to an optical waveguide core affecting a light of another optical waveguide core in the vicinity of a joining section of the two optical waveguide cores. This optical branching/coupling device includes: a first optical waveguide that is provided extending from one end side to other end side; a second optical waveguide that is provided extending on a separate route from the one end side to the other end side, the other end side of the second optical waveguide being joined to the other end side of the first optical waveguide; and a cladding layer that covers the periphery of the first optical waveguide and the second optical waveguide, wherein the first and second optical waveguides comprise a cured product of a photocuring resin.