-
公开(公告)号：US20230336338A1
公开(公告)日：2023-10-19
申请号：US18009399
申请日：2020-06-11
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Yuto SAGAE , Kazuhide NAKAJIMA , Taiji SAKAMOTO , Nobutomo HANZAWA , Takashi MATSUI , Noriyuki ARAKI , Shinichi AOZASA , Ryota IMADA , Yoko YAMASHITA
Abstract: It is an object of the present disclosure to reduce the risk of information exploitation by a malicious third party while allowing communication data to be demodulated in real time. An optical transmission system according to the present disclosure includes a transmitter which transmits an optical signal representing a cryptographic key and an optical signal representing communication data individually, an optical transmission path including a heterogeneous multi-core optical fiber having multiple cores, at least one of which has a different propagation delay time, the optical transmission path transmitting the optical signal representing the cryptographic key using a first core with a smaller delay among the multiple cores and the optical signal representing the communication data using a second core with a greater delay than the first core, and a receiver which individually receives the optical signals representing the cryptographic key and the communication data output from the individual cores of the optical transmission path and demodulates the received communication data on the basis of the received cryptographic key information.
-
公开(公告)号：US20220214496A1
公开(公告)日：2022-07-07
申请号：US17605758
申请日：2020-04-06
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Taiji SAKAMOTO , Kazuhide NAKAJIMA , Masaki WADA , Shinichi AOZASA , Takashi YAMAMOTO
Abstract: An object is to provide a multi-core configuration for acquiring a random mode coupling in a case of an arbitrary core refractive index.
A multi-core optical fiber according to the present invention is an optical fiber in which two or more core regions are arranged in a clad region having a refractive index at a minimum core interval Λ smaller than a refractive index of the cores, a configuration of the cores is that including one propagation mode, and the core configuration and the core interval are adjusted so that an inter-mode coupling coefficient between adjacent cores is within a range from 0.73 to 120 m−1.-
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
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：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
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：US20220337025A1
公开(公告)日：2022-10-20
申请号：US17762399
申请日：2019-09-26
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Shinichi AOZASA , Taiji SAKAMOTO , Kazuhide NAKAJIMA , Masaki WADA
Abstract: An objective of the present invention is to provide an optical amplifier having a cladding excitation configuration that improves amplification efficiency. The optical amplifier includes an optical amplification unit 36 in which n (n is a natural number equal to or greater than 2) amplification fibers 34 that optically amplify signal light propagating through cores with excitation light supplied to claddings and n−1 optical input/output units 35 that input/output the signal light to/from the cores and the outside of the amplification fibers 34 are connected in series such that the amplification fibers 34 and the optical input/output units 35 are disposed in an alternating manner, an excitation light generator 31 that outputs the excitation light in multi-mode, and optical multiplexer/demultiplexers 33 that cause the excitation light from the excitation light generator 31 that has been divided into two light beams to be incident on the claddings of the amplification fibers 34 disposed at both ends of the optical amplification unit 36 and cause the signal light to be input to/output from the cores of the amplification fibers 34 disposed at both ends of the optical amplification unit 36.
-
Patent Agency Ranking
公开(公告)号：US20220337020A1
公开(公告)日：2022-10-20
申请号：US17760713
申请日：2019-09-26
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Shinichi AOZASA , Taiji SAKAMOTO , Kazuhide NAKAJIMA , Masaki WADA
Abstract: An object is to provide an optical amplifier with a cladding pumped configuration that improves amplification efficiency. The optical amplifier according to the present invention includes a pump light conversion fiber 11 that converts first pump light L1 with a first wavelength propagating in a cladding into second pump light L2 with a second wavelength, an amplification fiber 13 that is connected to the pump light conversion fiber 11 and optically amplifies signal light Ls with the second pump light L2 supplied to the cladding from the pump light conversion fiber 11, and an oscillator 12 that causes the second pump light L2 to be reflected on two reflectors 15 and to reciprocate within the claddings of the pump light conversion fiber 11 and the amplification fiber 13 to cause laser oscillation of the second pump light L2.
-
公开(公告)号：US20220337016A1
公开(公告)日：2022-10-20
申请号：US17760697
申请日：2019-09-26
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Shinichi AOZASA , Taiji SAKAMOTO , Kazuhide NAKAJIMA , Masaki WADA
IPC: H01S3/067
Abstract: An objective is to provide an optical amplifier having a core excitation configuration that improves amplification efficiency. An optical amplifier according to the present invention includes an excitation light conversion fiber 11 that absorbs first excitation light L1 propagating in a cladding and having a first wavelength and emits, into a core, spontaneous emission light having a second wavelength, an oscillator 12 for causing the spontaneous emission light to be reflected on two reflectors 15 to reciprocate the light within the core of the excitation light conversion fiber 11 and laser-oscillating second excitation light L2 having the second wavelength, and an amplification fiber 13 that is connected to the excitation light conversion fiber 11 and amplifies signal light with the second excitation light L2 supplied from the excitation light conversion fiber 11 to the core.
-
公开(公告)号：US20240072507A1
公开(公告)日：2024-02-29
申请号：US18269611
申请日：2021-01-21
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Shinichi AOZASA , Taiji SAKAMOTO , Kazuhide NAKAJIMA , Takashi MATSUI
CPC classification number: H01S3/10023 , G02B6/0003
Abstract: The purpose of the present invention is to provide an optical fiber amplifier capable of seamlessly and collectively amplifying optical signals in a plurality of bands.
In order to achieve the aforementioned purpose, the optical fiber amplifier according to the present invention is the optical fiber amplifier that amplifies multiple wavelength bands, and in cross-section, one signal light primary propagation region, and a doped region where rare-earth ions have been added, wherein the doped region includes the rare-earth-doped optical fiber existing other than the propagation region. The optical fiber amplifier uses the fact that the main propagation regions of the signal light are made the same in the fiber cross-section of the rare-earth-doped optical fiber and the propagation regions of the signal light are partially different in the signal wavelength, and adds rare-earth ions to the partially different propagation regions to make amplification factors different for each signal wavelength and flatten the gain of each amplification wavelength band.-
公开(公告)号：US20230324604A1
公开(公告)日：2023-10-12
申请号：US18024559
申请日：2020-09-09
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Ryota IMADA , Yoko YAMASHITA , Takashi MATSUI , Taiji SAKAMOTO , Nobutomo HANZAWA , Noriyuki ARAKI , Shinichi AOZASA , Yuto SAGAE , Kazuhide NAKAJIMA
IPC: G02B6/02
CPC classification number: G02B6/02095
Abstract: Provided are an LPFG and an optical transmission system in which a mode conversion amount does not depend on a polarization state and an electric field distribution. The LPFG according to the present invention includes cavity rows (25-1 and 25-2) of cavities 15 periodically arranged in a core region 11 of the few-mode fiber 10 at a position away from a central axis z of the core region 11 in parallel with the central axis z. Each of the cavity rows (25-1 and 25-2) is located at a different position in a longitudinal direction of the few-mode fiber 10 (where the position in a z direction is different), and the cavity rows (25-1 and 25-2) are located at positions shifted by 90° on a cross section of the core region 11 with the center of the cross section of the core region 11 (the intersection of an x-axis and a y-axis) as an origin.
-
公开(公告)号：US20220344888A1
公开(公告)日：2022-10-27
申请号：US17762403
申请日：2019-09-26
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Shinichi AOZASA , Taiji SAKAMOTO , Kazuhide NAKAJIMA , Masaki WADA
IPC: H01S3/067
Abstract: An objective of the present invention is to provide an amplification fiber having a cladding excitation configuration that improves amplification efficiency and an optical amplifier. An amplification fiber (10) according to the present invention is a multi-core amplification fiber having, from one end (E1) to the other end (EE), a plurality of cores (11b) in a cladding (11a), and a total distance from the one end (E1) to the other end (EE) in which rare earth ions are doped differs depending on the types of cores (11b). The cores (11b) are preferably disposed such that the cores of the same type are not adjacent to each other. By arranging the types of the cores in this manner, requirements for inter-core crosstalk can be mitigated since the bands of signal light in the adjacent cores are different. As a result, a density of cladding excitation light can be increased by shortening the inter-core distance, and thus the amplification efficiency can be improved.
-
-
-
-
-
-
-
-
-
Search Results
14
records
(took 0.018 seconds)
