US 12,411,284 B2
Low-loss coupling between single-core and multi-core fibers
Stephan Lvovich Logunov, Corning, NY (US); and Pushkar Tandon, Painted Post, NY (US)
Assigned to Corning Incorporated, Corning, NY (US)
Filed by CORNING INCORPORATED, Corning, NY (US)
Filed on Sep. 20, 2022, as Appl. No. 17/948,733.
Claims priority of provisional application 63/249,874, filed on Sep. 29, 2021.
Prior Publication US 2023/0106986 A1, Apr. 6, 2023
Int. Cl. G02B 6/26 (2006.01); G02B 6/02 (2006.01); G02B 6/036 (2006.01)
CPC G02B 6/262 (2013.01) [G02B 6/02042 (2013.01); G02B 6/03633 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A coupler comprising:
a first end configured to optically couple with a plurality of single-core optical fibers;
a second end configured to optically couple with a multi-core optical fiber;
a plurality of cores that each extends from the first end to the second end,
the plurality of cores comprising a first core such that an outer diameter of the first core at the first end is larger than an outer diameter of the first core at the second end,
the first core comprising a relative refractive index Δ01maxA at the first end from 0.6% Δ to 0.8% Δ and the first core comprising a relative refractive index Δ1maxB at the second end from 0.5% Δ to 1.0% Δ relative to the refractive index of pure silica, and
the first core comprising a mode field diameter, at 1550 nm wavelength, of 9.5 microns or greater; and
an outer cladding surrounding the plurality of cores and extending from the first end to the second end such that an outer diameter of the outer cladding at the first end is larger than an outer diameter of the outer cladding at the second end, the outer cladding comprising a relative refractive index Δ0E from −0.20% Δ to 0.20% Δ at the first end and at the second end relative to the refractive index of pure silica,
wherein the coupler comprises a single, contiguous, conical glass member that tapers from the first end to the second end.