公开(公告)号：US20250118941A1

公开(公告)日：2025-04-10

申请号：US18832029

申请日：2022-02-03

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryota IMADA ,  Taiji SAKAMOTO ,  Shinichi AOZASA ,  Kazuhide NAKAJIMA

IPC: H01S3/067 ,  H01S3/10 ,  H01S3/16

Abstract: An optical amplifier of the present disclosure includes a rare-earth doped fiber including a plurality of cores, in which a v value of the plurality of cores of the rare-earth doped fiber is less than 2.405, the plurality of cores has a core pitch of a normalized coupling coefficient of 1.0×10−3 or more, and on injection of excitation light into a clad part of the rare-earth doped fiber in a state of being bent at a predetermined bending radius, propagating light in the rare-earth doped fiber is amplified with mode-dependent gain characteristics dependent on the bending radius.

公开(公告)号：US20240272375A1

公开(公告)日：2024-08-15

申请号：US18570431

申请日：2021-06-21

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yoshiteru ABE ,  Yoko YAMASHITA ,  Taiji SAKAMOTO ,  Takashi MATSUI ,  Kazuhide NAKAJIMA ,  Kazunori KATAYAMA

IPC: G02B6/38

CPC classification number: G02B6/3882

Abstract: An object of the present disclosure is to connect an optical fiber and an optical waveguide with a low loss. The present disclosure is an optical connector plug, including: an optical waveguide having two guide pin V-grooves engraved on one surface thereof and having a cross section of one or more cores appearing between cross sections of the guide pin V-grooves on one end face thereof; two guide pins separately arranged in the two guide pin V-grooves; a flat substrate so fixed as to tuck the two guide pins in the two guide pin V-grooves on the one surface of the optical waveguide; and a fixing member equipped with the optical waveguide, the two guide pins, and the flat substrate.

公开(公告)号：US20230341618A1

公开(公告)日：2023-10-26

申请号：US18020539

申请日：2020-08-12

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MATSUI ,  Kazuhide NAKAJIMA ,  Taiji SAKAMOTO ,  Yuto SAGAE

IPC: G02B27/00 ,  G02B6/02

CPC classification number: G02B6/02042 ,  G02B6/02028 ,  G02B27/0012

Abstract: The present invention is to provide a multi-core optical fiber that can expand its transmission wavelength band, and extend its transmission distance by reducing crosstalk, and also provide a method for designing the multi-core optical fiber. A multi-core optical fiber according to the present invention includes: four cores that are arranged in a square lattice pattern in a longitudinal direction; and a cladding region that is formed around the outer peripheral portions of the cores and has a lower refractive index than the cores, the absolute value of the relative refractive index difference between the cores and the cladding region being represented by Δ. In the multi-core optical fiber, the diameter of the cladding region is 125 ± 1 µm, the cutoff wavelength is 1.45 µm or shorter, the mode field diameter MFD at a wavelength of 1.55 µm is 9.5 to 10.0 µm, the bending loss at a wavelength of 1.625 µm and with a bending radius of 30 mm is 0.1 dB/100 turns or smaller, and the inter-core crosstalk at the wavelength of 1.625 µm is -47 dB/km or smaller.

公开(公告)号：US20220294537A1

公开(公告)日：2022-09-15

申请号：US17633902

申请日：2019-08-23

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Taiji SAKAMOTO ,  Masaki WADA ,  Takashi YAMAMOTO ,  Kazuhide NAKAJIMA

IPC: H04B10/61 ,  H04B10/2581 ,  H04B10/2575

Abstract: An object of the present invention is to provide an optical transmission system capable of easily controlling a transmission capacity and an optical signal quality even if a MIMO equalizer is provided. The optical transmission system according to the present invention is provided with an N×M MIMO equalizer, includes receivers (N units) equal in number to the spatial multiplexing order L of an optical fiber, and changes the number M of the signal beams of light transmitted through the optical fiber in the range of the spatial multiplex order L or less. The adjustment of the number M of signal beams of light makes it possible to adjust a transmission capacity and a signal quality of the optical transmission system even after construction of the transmission line.

公开(公告)号：US20200225407A1

公开(公告)日：2020-07-16

申请号：US16633424

申请日：2018-07-31

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Azusa URUSHIBARA ,  Taiji SAKAMOTO ,  Masaki WADA ,  Takashi YAMAMOTO ,  Kazuhide NAKAJIMA ,  Takayoshi MORI

IPC: G02B6/02 ,  H01S3/10 ,  H04B10/2581

Abstract: The optical fiber of the present invention includes a core, and a cladding that is provided on an outer periphery of the core and has a refractive index lower than a refractive index of the core region. In the optical fiber of the present invention, a V value representing a normalized frequency of an LP02 mode is greater than or equal to 4.8 and less than or equal to 6.4.

公开(公告)号：US20190196106A1

公开(公告)日：2019-06-27

申请号：US16322432

申请日：2017-08-01

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Masaki WADA ,  Taiji SAKAMOTO ,  Takayoshi MORI ,  Shinichi AOZASA ,  Takashi YAMAMOTO ,  Kazuhide NAKAJIMA

IPC: G02B6/26 ,  G02B6/036 ,  G02B6/02

Abstract: A differential mode attenuation compensator includes a first multi-mode optical fiber and a third multi-mode optical fiber in which a plurality of propagation modes propagate in a wavelength of a propagating optical signal; and a second multi-mode optical fiber including a core and a clad and arranged with a central axis aligned between the first multi-mode optical fiber and the third multi-mode optical fiber, in which each loss in the plurality of propagation modes is different in the first multi-mode optical fiber and the third multi-mode optical fiber.

公开(公告)号：US20190170931A1

公开(公告)日：2019-06-06

申请号：US16313724

申请日：2017-06-21

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Taiji SAKAMOTO ,  Takashi MATSUI ,  Kazuhide NAKAJIMA ,  Kotaro SAITOH

IPC: G02B6/02 ,  G02B6/38

Abstract: An optical connector is provided which includes at least one multi-core block fixing and holding a plurality of multi-core optical fibers in a state where a position in a direction orthogonal to an optical axis of each multi-core optical fiber and a rotation angle around the optical axis are in a predetermined state, and a ferrule including an accommodating portion accommodating the multi-core block.

公开(公告)号：US20180372954A1

公开(公告)日：2018-12-27

申请号：US16062034

申请日：2016-12-27

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MATSUI ,  Kazuhide NAKAJIMA ,  Taiji SAKAMOTO ,  Koutaro SAITO

IPC: G02B6/255 ,  G01B11/27 ,  G02B6/42 ,  G02B6/38

Abstract: An alignment apparatus that can efficiently align an optical fiber, and an alignment method will be provided.According to the embodiments, the alignment apparatus that aligns an optical fiber comprises an acquisition unit, a calculation unit, and a rotation processing unit. The acquisition unit acquires one or more side images of the optical fiber. The calculation unit calculates correlation coefficients between the luminances of the one or more side images and those of one or more reference side images. The rotation processing unit rotates the optical fiber in the axis direction of the optical fiber so that the correlation coefficients peak.