US 12,442,987 B2
Branch ratio measuring device, branch ratio measuring method, and optical multiplexing/demultiplexing circuit manufacturing method
Takui Uematsu, Musashino (JP); Hidenobu Hirota, Musashino (JP); and Hiroyuki Iida, Musashino (JP)
Assigned to NTT, Inc., Tokyo (JP)
Appl. No. 18/020,557
Filed by NTT, Inc., Tokyo (JP)
PCT Filed Aug. 12, 2020, PCT No. PCT/JP2020/030724
§ 371(c)(1), (2) Date Feb. 9, 2023,
PCT Pub. No. WO2022/034660, PCT Pub. Date Feb. 17, 2022.
Prior Publication US 2023/0324623 A1, Oct. 12, 2023
Int. Cl. G02B 6/35 (2006.01); G02B 6/26 (2006.01); G02B 6/293 (2006.01)
CPC G02B 6/3594 (2013.01) [G02B 6/262 (2013.01); G02B 6/2938 (2013.01); G02B 6/3588 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A branch ratio measuring device comprising:
an optical waveguide that has a cladding polished to a core or to a vicinity of the core, where the optical waveguide is configured to receive incoming light at one end of the core and output light at the other end of the core;
a first optical intensity measurement unit that is connected to one end of the core of the optical waveguide, and measures an optical intensity;
a second optical intensity measurement unit that is connected to the other end of the core of the optical waveguide, and measures an optical intensity; and
a partial reflection unit that is disposed between the other end of the core of the optical waveguide and the second optical intensity measurement unit, reflects part of light, and transmits remaining part of the light, wherein the second optical intensity measurement unit measures an optical intensity of the light that has passed through the partial reflection unit.