Fujikura Limited

Hokkaido University

Yoshimichi Amma

Katsuhiro Takenaga

Kunimasa Saitoh

Yusuke Sasaki

Shota Saito

Ryohei Fukumoto

An optical fiber preform production method includes: inserting at least one glass rod into at least one through-hole that penetrates a cladding glass body that is a cladding of an optical fiber; integrating a dummy rod by either integrating a solid dummy silica rod with a first end of the cladding glass body by heating the first end to close a first opening of the through-hole that opens in the first end, or forming a base end seal that closes the first opening in the first end and integrating the solid dummy silica rod with the base end; and closing a second opening of the through-hole that opens in a second end of the cladding glass body by heating and deforming the second end.

Optical fiber preform production method, optical fiber preform, and optical fiber production method

A multicore fiber includes a plurality of cores including a first core and a cladding surrounding the plurality of cores. The first core includes: an inner core; and an outer core surrounding the inner core with no gap and having a refractive index higher than a refractive index of the inner core and a refractive index of the cladding. The core is not doped with any rare earth element. At least two LP mode light beams at a predetermined wavelength propagate through the first core at an attenuation of 0.3 dB/km or less.

Multicore fiber

No core is disposed at the lattice point of a triangular lattice of a first layer LY. First coresandof the core elementsandare disposed at the lattice points of a second layer LY. A first coreof the core elementand the second coreare alternately disposed at the lattice points of a third layer LY. In a fourth layer LY, no core is disposed at six lattice points, and the first coresandof the core elementsandare disposed at the other lattice points. The second coresare adjacent to the lattice points of the fourth layer LY, at which no core is disposed. The effective refractive indexes of the core elements adjacent to each other are different from each other.

A method of connecting multicore fibersincludes a shaping step Sand a fusing step S. The multicore fiberssatisfy Y&#x2267;20, where a distance from a center of a corelocated on the outer periphery side of a cladto a side surface of the cladis defined as Y &#x3bc;m. The shaping step Sincludes heating a end surfacesto satisfy 0&#x3c;X/Y&#x2266;0.0054Y+0.268, where a distance in a longitudinal direction from a portion of each multicore fiberlocated at an end in the longitudinal direction on each shaped end surfaceto a position at which the end surfaceand the side surface of the cladmeet each other is defined as X &#x3bc;m.

Multicore fiber connection method and multicore fiber connector using same

In a C band and an L band, the effective refractive indices of light propagating through the coresandadjacent to each other are different from each other such that a magnitude of crosstalk of light of a highest-order LP mode commonly propagating through the coresandadjacent to each other between the coresandadjacent to each other becomes a peak at a bending diameter smaller than a diameter of 100 mm, and the core has a higher refractive index in a center portion than in an outer circumferential portion such that a differential mode group delay of the coresandis 700 picoseconds/km or less.

Growing community of inventors

Sakura, Japan

Yoshimichi Amma