US 12,449,589 B2
Multicore optical fiber
Takemi Hasegawa, Osaka (JP); Takahiro Suganuma, Osaka (JP); and Hirotaka Sakuma, Osaka (JP)
Assigned to Sumitomo Electric Industries, Ltd., Osaka (JP)
Appl. No. 18/026,615
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
PCT Filed Oct. 13, 2021, PCT No. PCT/JP2021/037886
§ 371(c)(1), (2) Date Mar. 16, 2023,
PCT Pub. No. WO2022/085534, PCT Pub. Date Apr. 28, 2022.
Claims priority of application No. 2020-177977 (JP), filed on Oct. 23, 2020.
Prior Publication US 2023/0333311 A1, Oct. 19, 2023
Int. Cl. G02B 6/02 (2006.01)
CPC G02B 6/02042 (2013.01) [G02B 6/02333 (2013.01); G02B 6/02395 (2013.01)] 1 Claim
OG exemplary drawing
 
1. A multicore optical fiber comprising:
a plurality of cores comprised of silica glass;
a common cladding comprised of silica glass and surrounding the plurality of cores, the common cladding having a refractive index lower than a refractive index of each of the plurality of cores; and
a resin coating surrounding the common cladding,
wherein each of the plurality of cores contains chlorine at 10000 ppm or more in at least part thereof,
wherein a concentration of the chlorine is 2000 ppm or less at a core-cladding boundary between each of the plurality of cores and the common cladding, and
wherein, in a transition region of each of the plurality of cores that includes the core-cladding boundary, and has a width of 1 μm or more and 5 μm or less, the concentration of the chlorine continuously decreases in a direction from a refractive index centroid of each of the plurality of cores toward the common cladding.