US 12,105,326 B2
Optical multiplexer reduced in background light
Akira Himeno, Fukui (JP); Koichi Horii, Fukui (JP); Toshio Katsuyama, Fukui (JP); Shoji Yamada, Fukui (JP); and Akira Nakao, Fukui (JP)
Assigned to SEIREN KST CORP., Fukui (JP); and UNIVERSITY OF FUKUI, Fukui (JP)
Appl. No. 17/909,078
Filed by SEIREN KST CORP., Fukui (JP); and UNIVERSITY OF FUKUI, Fukui (JP)
PCT Filed Feb. 26, 2021, PCT No. PCT/JP2021/007351
§ 371(c)(1), (2) Date Sep. 2, 2022,
PCT Pub. No. WO2021/177167, PCT Pub. Date Sep. 10, 2021.
Claims priority of application No. 2020-036933 (JP), filed on Mar. 4, 2020.
Prior Publication US 2023/0084204 A1, Mar. 16, 2023
Int. Cl. G02B 6/293 (2006.01)
CPC G02B 6/2938 (2013.01) 5 Claims
OG exemplary drawing
 
1. An optical multiplexer to which a plurality of light beams having different wavelengths are inputted from respective waveguides, and which outputs a multiple light beam obtained by multiplexing the plurality of light beams by a directional coupler, wherein
the optical multiplexer includes a reflection groove configured to reduce background light by reflecting excess light outputted from a discard port of the directional coupler, and
a cladding layer ranging from the reflection groove to an output end surface of the optical multiplexer is removed, with a part of the cladding layer around an output port of the optical multiplexer being left intact.