PURPOSE: To facilitate constituting a star coupler without increment of the overall length, by forming plural faces including the axis of the self-focusing lens of the 1/4 cycle length into total reflection faces and by connecting another self-converging lens of the 1/4 cycle length to one end face of the total reflection face.
CONSTITUTION: Lenses 9 and 10 are self-converging rod lenses of the 1/4 cycle length, and one lens 9 is provided with total reflection faces on three faces 10 which include the axis and intersect one another at, for example, 60°. The light incident from incident position 12 of one end face has the wave face divided in the lens, and respective emitted lights are divided equally in emission position 13. Consequently, optical fibers are connected to incident position 12 and emission position 13 to constitute a star coupler. Since incident and emission fibers are arranged on the same circle at center angle 60°, seven fibers 14 are bundled and used. As a result, a star coupler can be constituted easily without increment of the overall length.
SERIZAWA AKIMOTO
HATSUTORI KATSUJI
