WO2022044181A1 - Optical fiber and optical transmission line - Google Patents

Optical fiber and optical transmission line Download PDF

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Publication number
WO2022044181A1
WO2022044181A1 PCT/JP2020/032293 JP2020032293W WO2022044181A1 WO 2022044181 A1 WO2022044181 A1 WO 2022044181A1 JP 2020032293 W JP2020032293 W JP 2020032293W WO 2022044181 A1 WO2022044181 A1 WO 2022044181A1
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Prior art keywords
optical fiber
core
optical
lens
transmission line
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PCT/JP2020/032293
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French (fr)
Japanese (ja)
Inventor
悠途 寒河江
和秀 中島
泰志 坂本
信智 半澤
隆 松井
則幸 荒木
真一 青笹
諒太 今田
陽子 山下
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日本電信電話株式会社
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Priority to PCT/JP2020/032293 priority Critical patent/WO2022044181A1/en
Publication of WO2022044181A1 publication Critical patent/WO2022044181A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/32—Optical coupling means having lens focusing means positioned between opposed fibre ends

Definitions

  • This disclosure relates to optical fibers and optical transmission lines.
  • an optical device using a spatial optical system as disclosed in a non-patent document uses a plurality of lenses and arranges them in a complicated manner, so that there is a problem that it is difficult to reduce the cost and space.
  • an object of the present invention to provide an optical fiber and an optical transmission line capable of space division multiplexing at low cost and space saving.
  • the optical fiber according to the present invention has a built-in lens function.
  • the optical fiber according to the present invention includes a lens unit having a lens function with respect to light propagating in the core.
  • the optical transmission line according to the present invention includes the optical fiber and a propagating optical fiber that propagates light through the lens portion of the optical fiber. Since this optical fiber includes a lens unit, it is not necessary to input and output spatially multiplexed light to and from the optical fiber using a complicated spatial optical system, and it is possible to reduce the cost and space. Therefore, the present invention can provide an optical fiber and an optical transmission line capable of space division multiplexing at low cost and space saving.
  • the optical fiber according to the present invention has one core and is in contact with at least one lens portion. Further, the optical fiber according to the present invention has a plurality of cores, each of which is in contact with at least one lens portion.
  • the optical fiber according to the present invention is characterized in that the lens portion that is not in contact with the core is arranged at a position that receives light from the lens portion that is in contact with the core. Multiple light propagating in the core can be branched.
  • the lens portion of the optical fiber according to the present invention is characterized by having a higher refractive index than the core. Further, the lens portion of the optical fiber according to the present invention is characterized by being hollow.
  • the present invention can provide an optical fiber and an optical transmission line capable of space division multiplexing at low cost and space saving.
  • FIG. 1 is a diagram illustrating an optical fiber 301 of the present embodiment.
  • the optical fiber 301 includes a core 11, a cladding 12 having a refractive index lower than that of the core 11, and a lens unit 13 having a lens function for light propagating through the core 11.
  • the optical fiber 301 has a lens unit 13 having a lens structure inside, and the lens unit 13 controls the propagation path of the propagated light propagating through the core 11 at the position and angle at which the lens unit 13 is arranged.
  • the lens portion 13 can be realized by adding an impurity to a desired position of quartz glass (optical fiber base material) and making the refractive index larger than that of the core 11.
  • quartz glass optical fiber base material
  • the impurity-added region is extended by optical fiber spinning, so that a desired lens effect may not be obtained. Therefore, there is also a method of changing the refractive index by using a femtosecond pulse laser.
  • the lens portion 13 may be hollow. In this method, the lens portion 13 can be formed by changing the refractive index at an arbitrary position of the optical fiber after spinning the optical fiber. Further, in this method, the lens portion 13 having an arbitrary shape can be formed by controlling the pulsed laser irradiation location.
  • FIG. 2 is a diagram illustrating the optical fiber 302 of the present embodiment.
  • the optical fiber 302 has a plurality of cores, and each of the cores is in contact with at least one lens portion.
  • the optical fiber 302 of FIG. 2 has m cores (11-1 to 11-m) (m is an integer of 2 or more). Each core (11-1 to 11-m) is in contact with the lens portion (13-1 to 13-m).
  • the lens portion (13-1 to 13-m) is arranged near the end surface 14 of the optical fiber 302.
  • the optical fiber 302 is a fan-in / fan-out device.
  • each core (11-1 to 11-m) propagates signal light (L1 to Lm) in the end face 14 direction.
  • the signal light (L1 to Lm) is emitted from the end face 14 in the radial direction determined by the lens portion (13-1 to 13-m), and is incident on the single core fiber (51-1 to 51-m).
  • the optical fiber 302 functions as a fan-out device.
  • the optical fiber 302 can be reduced in cost and space as compared with a fan-out device using a conventional spatial optical system.
  • the optical fiber 302 can be made into a fan-out device having wavelength selectivity. Specifically, by setting the distance between the lens unit 13-1 and the incident portion of the single-core optical fiber 51-1 as the focal length of the lens unit 13-1 at the wavelength ⁇ 1 , the lens unit 13-1 As for the signal light L1 emitted from, only the wavelength ⁇ 1 is incident on the core of the single core fiber 51-1.
  • the distance between the lens unit 13-i (i is an integer from 1 to m) and the incident portion of the single-core optical fiber 51-i is determined by the wavelength ⁇ j (j is 1 to n) of the lens unit 13-i.
  • FIG. 3 is a diagram illustrating the optical fiber 303 of the present embodiment.
  • the optical fiber 303 has one core and is in contact with at least one lens portion.
  • the optical fiber 303 of FIG. 3 has one core 11 and a plurality of lens portions (13-1 to 13-8). Then, the lens portion (13-1, 13-3, 13-5, 13-7) comes into contact with the core 11, but the lens portion (13-2, 13-4, 13-6, 13-8) is clad. It is in 12 and is not in contact with the core 11.
  • the optical fiber 303 is a power splitter.
  • the lens portions (13-2, 13-4, 13-6, 13-8) that are not in contact with the core 11 are the lens portions (13-1, 13-3, 13-5,) that are in contact with the core 11. It is arranged at a position to receive the light from 13-7).
  • the lens unit 13-1 branches a part of the signal light L1 propagating in the core 11 and radiates it to the outside of the core 11.
  • the signal light L1 radiated to the outside of the core 11 reaches the lens portion 13-2 and is bent in the end face 14 direction by the lens portion 13-2.
  • the focal point of each lens unit is adjusted so that the signal light L1 can be focused on the end face 14 via each lens unit.
  • the lens unit 13-3 branches a part of the signal light L1 remaining in the core 11 at the lens unit 13-1 and radiates it to the outside of the core 11.
  • the signal light L1 radiated to the outside of the core 11 reaches the lens portion 13-4 and is bent in the end face 14 direction by the lens portion 13-4.
  • the focal point of each lens unit is adjusted so that the signal light L1 can be focused on the end face 14 via each lens unit.
  • the multi-core optical fiber 52 is physically contacted and connected to the end face 14.
  • the optical fiber 303 branches the signal light L1 at the lens portion and is incident on each core (21-1 to 21-n) of the multi-core optical fiber 52.
  • the optical fiber 303 functions as a fan-in device.
  • the optical fiber 303 can be reduced in cost and space as compared with a fan-in device using a conventional spatial optical system.
  • the signal light L1 is wavelength division multiplexing transmission including a plurality of wavelengths of ⁇ 1 to ⁇ n , each of between the lens unit (13-2, 13-4, 13-6, 13-8) and the end face 14.
  • the optical fiber 303 can be made into a fan-in device having wavelength selectivity. Specifically, by setting the distance between the lens unit 13-2 and the end face 14 as the focal length of the lens unit 13-2 at the wavelength ⁇ 1 , the signal light L1 emitted from the lens unit 13-2 has the wavelength ⁇ . Only 1 will be incident on the core 21-1 of the multi-core fiber 52.
  • the lens unit 13-k As for the signal light L1 emitted from 13-k, only the wavelength ⁇ j is incident on the core 21-j of the multi-core fiber 52. However, signal light L1 having a plurality of wavelengths ( ⁇ 1 to ⁇ n ) is incident on the core 21-j of the multi-core optical fiber 52 that is directly connected to the core 11 of the optical fiber 303.
  • FIG. 4 is a diagram illustrating the optical fiber 304 of the present embodiment.
  • the optical fiber 304 has one core and is in contact with at least one lens portion.
  • the optical fiber 304 of FIG. 4 has one core 11 and one lens unit 13 formed on the core 11.
  • the optical fiber 304 converts the mode field diameter.
  • a single core optical fiber 53 is connected to the end face 14 of the optical fiber 304.
  • the lens unit 13 collects the signal light L1. In this way, by using the optical fiber 304, it is possible to connect optical fibers of different MFDs with low loss.
  • the lens portion formed by the femtosecond pulse laser described in the second embodiment is obtained by altering the quartz glass structure to change the refractive index, and the difference in the refractive index at the lens boundary is limited. Therefore, it is difficult to shorten the focal length of the lens. Therefore, a hole is provided by a high-intensity femtosecond pulse laser.
  • the lens portion 13 with holes the difference in the refractive index at the lens boundary can be increased.
  • the lens portion 13 a hole a short focal length can be obtained, the length of the optical fiber (301 to 304) can be shortened, and space saving of a fan-in / fan-out device or a power splitter can be realized.
  • an optical transmission line including an optical fiber (301 to 304) and a propagation optical fiber that propagates light through a lens portion of the optical fiber will be described.
  • FIG. 5 is a diagram illustrating an optical transmission line 401 of the present embodiment.
  • the optical transmission line 401 is a communication system configured by connecting optical fibers having different MFDs.
  • the optical transmission line 401 includes the optical fiber 304 described in the fourth embodiment.
  • the signal light L1 transmitted from the transmitter 41 has an MFD converted from a1 to a2 by the lens unit 13 of the optical fiber 304-1 and is incident on the transmission line 53.
  • the signal light L1 propagating through the transmission path 53 has an MFD converted from a 2 to a 1 by the lens unit 13 of the optical fiber 304-2, and is received by the receiver 42.
  • the optical transmission line 401 can suppress optical loss due to MFD mismatch due to the above configuration.
  • FIG. 6 is a diagram illustrating the optical transmission line 402 of the present embodiment.
  • the optical transmission line 402 is a communication system of a space division multiplex transmission line.
  • the optical transmission line 402 includes a plurality of transmitters 41, a plurality of receivers 42, a space division multiplex transmission line 55, and an optical fiber 302 described in the second embodiment.
  • the optical fiber 302 described in the second embodiment is used as a fan-in / fan-out device or a power splitter as an input / output device of a space-divided multiplex transmission line.
  • the signal light from the transmitters 41 (1 to N) is incident on the optical fiber 302-1.
  • the optical fiber 302-1 is connected to a space-divided multiplex transmission line 55 (for example, a multi-core optical fiber), and each signal light is incident on each optical path (each core) of the space-divided multiplex transmission line 55.
  • the signal light propagating through the space division multiplexing transmission line 55 is taken out from each space channel by the optical fiber 302-2 and received by the receivers 42 (1 to N).
  • the optical transmission line 402 can be reduced in cost and space at the transmission / reception end as compared with a time division multiplexing transmission system using a conventional space optical system.
  • the present invention can be used for maintenance of an optical communication network.
  • Lens unit 25 Core 41: Transmitter 42: Receivers 51, 51-1, 51-2, ..., 51-m: 52: Multi-core optical fiber 53: Single-core optical fiber 55: Spatial division multiple transmission line 301, 302, 303, 304: Optical fiber 401, 402: Optical transmission line

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

The purpose of the present invention is to provide an optical fiber and optical transmission line capable of space division multiplexing with a low cost and a small footprint.　An optical fiber 301 comprises a core 11, a cladding 12 with a lower refractive index than the core 11, and a lens part 13 that functions as a lens for light propagating through the core 11. The optical fiber 301 has the lens part 13 of a lens structure on the inside thereof, and the lens part 13 controls the propagation path of propagated light that has propagated through the core 11, at a position and angle at which the lens part 13 is disposed.

Description

光ファイバ及び光伝送路Optical fiber and optical transmission line
　本開示は、光ファイバ及び光伝送路に関する。 This disclosure relates to optical fibers and optical transmission lines.
　光通信技術の普及及び発展に伴って、光ファイバおよびそれを含んだデバイスの低コスト化、省スペース化が求められている。例えば近年の空間分割多重技術ではコア又はモードの伝送空間チャネルを光ファイバへ入力、またそれらを光ファイバから抽出及び分離する技術が議論されており、様々な方式が提案されている（例えば、非特許文献１、２を参照。）。その中でレンズなどを用いて信号光の入力及び抽出を行う空間光学系は様々な伝送空間チャネルに柔軟に対応できるため、注目されている。 With the spread and development of optical communication technology, it is required to reduce the cost and space of optical fibers and devices including them. For example, in recent spatial division multiplex technology, a technique for inputting a core or mode transmission spatial channel to an optical fiber and extracting and separating them from the optical fiber has been discussed, and various methods have been proposed (for example, non-optical fiber). See Patent Documents 1 and 2). Among them, spatial optical systems that input and extract signal light using a lens or the like are attracting attention because they can flexibly support various transmission spatial channels.
　しかし、非特許文献で開示されるような空間光学系を用いた光デバイスは複数のレンズを用い、それを複雑に配置することから低コスト化と省スペース化が困難という課題がある。 However, an optical device using a spatial optical system as disclosed in a non-patent document uses a plurality of lenses and arranges them in a complicated manner, so that there is a problem that it is difficult to reduce the cost and space.
　そこで、本発明は、上記課題を解決するために、低コストと省スペースで空間分割多重が可能な光ファイバ及び光伝送路を提供することを目的とする。 Therefore, in order to solve the above problems, it is an object of the present invention to provide an optical fiber and an optical transmission line capable of space division multiplexing at low cost and space saving.
　上記目的を達成するために、本発明に係る光ファイバはレンズ機能を内蔵することとした。 In order to achieve the above object, the optical fiber according to the present invention has a built-in lens function.
　具体的には、本発明に係る光ファイバは、コアを伝搬する光に対してレンズの機能を持つレンズ部を備える。また、本発明に係る光伝送路は、前記光ファイバと、前記光ファイバの前記レンズ部を介する光を伝搬する伝搬光ファイバと、を備える。本光ファイバは、レンズ部を備えるため、複雑な空間光学系を用いて空間多重光を光ファイバに入出力することが不要となり、低コスト化且つ省スペース化することができる。従って、本発明は、低コストと省スペースで空間分割多重が可能な光ファイバ及び光伝送路を提供することができる。 Specifically, the optical fiber according to the present invention includes a lens unit having a lens function with respect to light propagating in the core. Further, the optical transmission line according to the present invention includes the optical fiber and a propagating optical fiber that propagates light through the lens portion of the optical fiber. Since this optical fiber includes a lens unit, it is not necessary to input and output spatially multiplexed light to and from the optical fiber using a complicated spatial optical system, and it is possible to reduce the cost and space. Therefore, the present invention can provide an optical fiber and an optical transmission line capable of space division multiplexing at low cost and space saving.
　本発明に係る光ファイバの前記コアは１つであり、少なくとも１つの前記レンズ部と接触していることを特徴とする。また、本発明に係る光ファイバの前記コアは複数であり、前記コアのそれぞれは少なくとも１つの前記レンズ部と接触していることを特徴とする。 The optical fiber according to the present invention has one core and is in contact with at least one lens portion. Further, the optical fiber according to the present invention has a plurality of cores, each of which is in contact with at least one lens portion.
　本発明に係る光ファイバは、前記コアに接触していない前記レンズ部が、前記コアに接触している前記レンズ部からの光を受ける位置に配置されていることを特徴とする。コアを伝搬する光を複数分岐することができる。 The optical fiber according to the present invention is characterized in that the lens portion that is not in contact with the core is arranged at a position that receives light from the lens portion that is in contact with the core. Multiple light propagating in the core can be branched.
　例えば、本発明に係る光ファイバの前記レンズ部は、前記コアより屈折率が大きいことを特徴とする。また、本発明に係る光ファイバの前記レンズ部は、空洞であることを特徴とする。 For example, the lens portion of the optical fiber according to the present invention is characterized by having a higher refractive index than the core. Further, the lens portion of the optical fiber according to the present invention is characterized by being hollow.
　本発明は、低コストと省スペースで空間分割多重が可能な光ファイバ及び光伝送路を提供することができる。 The present invention can provide an optical fiber and an optical transmission line capable of space division multiplexing at low cost and space saving.
本発明に係る光ファイバを説明する図である。It is a figure explaining the optical fiber which concerns on this invention. 本発明に係る光ファイバを説明する図である。It is a figure explaining the optical fiber which concerns on this invention. 本発明に係る光ファイバを説明する図である。It is a figure explaining the optical fiber which concerns on this invention. 本発明に係る光ファイバを説明する図である。It is a figure explaining the optical fiber which concerns on this invention. 本発明に係る光伝送路を説明する図である。It is a figure explaining the optical transmission line which concerns on this invention. 本発明に係る光伝送路を説明する図である。It is a figure explaining the optical transmission line which concerns on this invention.
　添付の図面を参照して本発明の実施形態を説明する。以下に説明する実施形態は本発明の実施例であり、本発明は、以下の実施形態に制限されるものではない。なお、本明細書及び図面において符号が同じ構成要素は、相互に同一のものを示すものとする。 An embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In addition, the components having the same reference numerals in the present specification and the drawings shall indicate the same components.
（実施形態１）
　図１は、本実施形態の光ファイバ３０１を説明する図である。光ファイバ３０１は、コア１１、コア１１より屈折率が低いクラッド１２、及びコア１１を伝搬する光に対してレンズの機能を持つレンズ部１３を備える。光ファイバ３０１は、内部にレンズ構造のレンズ部１３を有しており、レンズ部１３を配置する位置や角度でコア１１を伝搬してきた伝搬光の伝搬経路をレンズ部１３で制御する。 (Embodiment 1)
FIG. 1 is a diagram illustrating an optical fiber 301 of the present embodiment. The optical fiber 301 includes a core 11, a cladding 12 having a refractive index lower than that of the core 11, and a lens unit 13 having a lens function for light propagating through the core 11. The optical fiber 301 has a lens unit 13 having a lens structure inside, and the lens unit 13 controls the propagation path of the propagated light propagating through the core 11 at the position and angle at which the lens unit 13 is arranged.
　レンズ部１３は、石英ガラス（光ファイバ母材）の所望の位置に不純物を添加し、コア１１より屈折率を大きくすることで実現できる。
　ここで、一般的な光ファイバ母材への不純物の添加は光ファイバ紡糸によって不純物添加領域が延伸されるため、所望のレンズ効果が得られない場合もある。そこで、フェムト秒パルスレーザを用いて屈折率を変化させる手法もある。例えば、レンズ部１３を、空洞としてもよい。本手法は、光ファイバ紡糸後に光ファイバの任意位置の屈折率を変化させてレンズ部１３を形成することができる。また、本手法は、パルスレーザ照射箇所を制御することにより任意の形状のレンズ部１３を形成することもできる。 The lens portion 13 can be realized by adding an impurity to a desired position of quartz glass (optical fiber base material) and making the refractive index larger than that of the core 11.
Here, when impurities are added to a general optical fiber base material, the impurity-added region is extended by optical fiber spinning, so that a desired lens effect may not be obtained. Therefore, there is also a method of changing the refractive index by using a femtosecond pulse laser. For example, the lens portion 13 may be hollow. In this method, the lens portion 13 can be formed by changing the refractive index at an arbitrary position of the optical fiber after spinning the optical fiber. Further, in this method, the lens portion 13 having an arbitrary shape can be formed by controlling the pulsed laser irradiation location.
（実施形態２）
　図２は、本実施形態の光ファイバ３０２を説明する図である。光ファイバ３０２は、コアが複数であり、前記コアのそれぞれは少なくとも１つのレンズ部と接触している。図２の光ファイバ３０２は、ｍ個のコア（１１－１～１１－ｍ）を有している（ｍは２以上の整数）。そして、それぞれのコア（１１－１～１１－ｍ）は、レンズ部（１３－１～１３－ｍ）と接触している。なお、レンズ部（１３－１～１３－ｍ）は、光ファイバ３０２の端面１４付近に配置されている。光ファイバ３０２は、ファンイン・ファンアウトデバイスである。 (Embodiment 2)
FIG. 2 is a diagram illustrating the optical fiber 302 of the present embodiment. The optical fiber 302 has a plurality of cores, and each of the cores is in contact with at least one lens portion. The optical fiber 302 of FIG. 2 has m cores (11-1 to 11-m) (m is an integer of 2 or more). Each core (11-1 to 11-m) is in contact with the lens portion (13-1 to 13-m). The lens portion (13-1 to 13-m) is arranged near the end surface 14 of the optical fiber 302. The optical fiber 302 is a fan-in / fan-out device.
　光ファイバ３０２の端面１４には、物理的に接触していないｍ本の単一コア光ファイバ（５１－１～５１－ｍ）が配置されている。各コア（１１－１～１１－ｍ）は、それぞれ信号光（L１～Lｍ）を端面１４方向に伝搬する。信号光（L１～Lｍ）は、端面１４からレンズ部（１３－１～１３－ｍ）によって決まる放射方向へ出射し、単一コアファイバ（５１－１～５１－ｍ）へ入射される。このように、光ファイバ３０２は、ファンアウトデバイスとして機能する。光ファイバ３０２は、従来の空間光学系を用いたファンアウトデバイスと比較し、低コスト化且つ省スペース化を図れる。 On the end face 14 of the optical fiber 302, m single-core optical fibers (51-1 to 51-m) that are not in physical contact are arranged. Each core (11-1 to 11-m) propagates signal light (L1 to Lm) in the end face 14 direction. The signal light (L1 to Lm) is emitted from the end face 14 in the radial direction determined by the lens portion (13-1 to 13-m), and is incident on the single core fiber (51-1 to 51-m). In this way, the optical fiber 302 functions as a fan-out device. The optical fiber 302 can be reduced in cost and space as compared with a fan-out device using a conventional spatial optical system.
 また、信号光（Ｌ１～Ｌｍ）がλ１～λｎの複数波長を含む波長分割多重伝送である場合、レンズ部（１３－１～１３－ｍ）と単一コアファイバ（５１－１～５１－ｍ）と間の各距離を調整することで、光ファイバ３０２を波長選択性を有したファンアウトデバイスとすることができる。具体的には、レンズ部１３－１と単一コア光ファイバ５１－１の入射部との距離を、レンズ部１３－１の波長λ１での焦点距離とすることで、レンズ部１３－１から出射した信号光Ｌ１は波長λ１のみが単一コアファイバ５１－１のコアに入射するようになる。同様に、レンズ部１３－ｉ（ｉは１からｍの整数）と単一コア光ファイバ５１－ｉの入射部との距離を、レンズ部１３－ｉの波長λｊ（ｊは１からｎの整数）での焦点距離とすることで、レンズ部１３－ｉから出射した信号光Ｌｉは波長λｊのみが単一コアファイバ５１－ｉのコアに入射するようになる。 Further, when the signal light (L1 to Lm) is wavelength division multiplexing transmission including a plurality of wavelengths of λ 1 to λ n , the lens unit (13-1 to 13-m) and the single core fiber (51-1 to 51). By adjusting each distance between -m) and, the optical fiber 302 can be made into a fan-out device having wavelength selectivity. Specifically, by setting the distance between the lens unit 13-1 and the incident portion of the single-core optical fiber 51-1 as the focal length of the lens unit 13-1 at the wavelength λ 1 , the lens unit 13-1 As for the signal light L1 emitted from, only the wavelength λ 1 is incident on the core of the single core fiber 51-1. Similarly, the distance between the lens unit 13-i (i is an integer from 1 to m) and the incident portion of the single-core optical fiber 51-i is determined by the wavelength λ j (j is 1 to n) of the lens unit 13-i. By setting the focal length at (an integer), only the wavelength λ j of the signal light Li emitted from the lens unit 13-i is incident on the core of the single core fiber 51-i.
（実施形態３）
　図３は、本実施形態の光ファイバ３０３を説明する図である。光ファイバ３０３は、コアが１つであり、少なくとも１つのレンズ部と接触している。図３の光ファイバ３０３は、１個のコア１１と複数のレンズ部（１３－１～１３－８）を有している。そして、レンズ部（１３－１、１３－３、１３－５、１３－７）はコア１１に接触するが、レンズ部（１３－２、１３－４、１３－６、１３－８）はクラッド１２内にあり、コア１１に非接触である。光ファイバ３０３は、パワースプリッタである。 (Embodiment 3)
FIG. 3 is a diagram illustrating the optical fiber 303 of the present embodiment. The optical fiber 303 has one core and is in contact with at least one lens portion. The optical fiber 303 of FIG. 3 has one core 11 and a plurality of lens portions (13-1 to 13-8). Then, the lens portion (13-1, 13-3, 13-5, 13-7) comes into contact with the core 11, but the lens portion (13-2, 13-4, 13-6, 13-8) is clad. It is in 12 and is not in contact with the core 11. The optical fiber 303 is a power splitter.
　コア１１に接触していないレンズ部（１３－２、１３－４、１３－６、１３－８）は、コア１１に接触しているレンズ部（１３－１、１３－３、１３－５、１３－７）からの光を受ける位置に配置されている。レンズ部１３－１は、コア１１を伝搬する信号光Ｌ１の一部を分岐してコア１１外へ放射する。コア１１外に放射された信号光Ｌ１は、レンズ部１３－２に到達し、レンズ部１３－２で端面１４方向へ曲げられる。ここで、各レンズ部の焦点は、信号光Ｌ１が各レンズ部を経由して端面１４で集光できるように調整される。
　また、レンズ部１３－３は、レンズ部１３－１でコア１１内に残存した信号光Ｌ１の一部を分岐してコア１１外へ放射する。コア１１外に放射された信号光Ｌ１は、レンズ部１３－４に到達し、レンズ部１３－４で端面１４方向へ曲げられる。
　以下、レンズ部（１３－５～１３－８）も同様である。ここで、各レンズ部の焦点は、信号光Ｌ１が各レンズ部を経由して端面１４で集光できるように調整される。 The lens portions (13-2, 13-4, 13-6, 13-8) that are not in contact with the core 11 are the lens portions (13-1, 13-3, 13-5,) that are in contact with the core 11. It is arranged at a position to receive the light from 13-7). The lens unit 13-1 branches a part of the signal light L1 propagating in the core 11 and radiates it to the outside of the core 11. The signal light L1 radiated to the outside of the core 11 reaches the lens portion 13-2 and is bent in the end face 14 direction by the lens portion 13-2. Here, the focal point of each lens unit is adjusted so that the signal light L1 can be focused on the end face 14 via each lens unit.
Further, the lens unit 13-3 branches a part of the signal light L1 remaining in the core 11 at the lens unit 13-1 and radiates it to the outside of the core 11. The signal light L1 radiated to the outside of the core 11 reaches the lens portion 13-4 and is bent in the end face 14 direction by the lens portion 13-4.
Hereinafter, the same applies to the lens portions (13-5 to 13-8). Here, the focal point of each lens unit is adjusted so that the signal light L1 can be focused on the end face 14 via each lens unit.
　また、端面１４には、マルチコア光ファイバ５２が物理的に接触して接続される。光ファイバ３０３は、前述のようにレンズ部で信号光Ｌ１を分岐し、マルチコア光ファイバ５２の各コア（２１－１～２１－ｎ）に入射する。この光ファイバ３０３は、ファンインデバイスとして機能する。光ファイバ３０３は、従来の空間光学系を用いたファンインデバイスと比較し、低コスト化且つ省スペース化を図れる。 Further, the multi-core optical fiber 52 is physically contacted and connected to the end face 14. As described above, the optical fiber 303 branches the signal light L1 at the lens portion and is incident on each core (21-1 to 21-n) of the multi-core optical fiber 52. The optical fiber 303 functions as a fan-in device. The optical fiber 303 can be reduced in cost and space as compared with a fan-in device using a conventional spatial optical system.
　また、信号光Ｌ１がλ１～λｎの複数波長を含む波長分割多重伝送である場合、レンズ部（１３－２、１３－４、１３－６、１３－８）と端面１４と間の各距離を調整することで、光ファイバ３０３を波長選択性を有したファンインデバイスとすることができる。具体的には、レンズ部１３－２と端面１４との距離を、レンズ部１３－２の波長λ１での焦点距離とすることで、レンズ部１３－２から出射した信号光Ｌ１は波長λ１のみがマルチコアファイバ５２のコア２１－１に入射するようになる。同様に、レンズ部１３－ｋ（ｋは偶数）と端面１４との距離を、レンズ部１３－ｋの波長λｊ（ｊは１からｎの整数）での焦点距離とすることで、レンズ部１３－ｋから出射した信号光Ｌ１は波長λｊのみがマルチコアファイバ５２のコア２１－ｊに入射するようになる。ただし、光ファイバ３０３のコア１１と直接接続しているマルチコア光ファイバ５２のコア２１－ｊには、複数波長（λ１～λｎ）の信号光Ｌ１が入射される。 Further, when the signal light L1 is wavelength division multiplexing transmission including a plurality of wavelengths of λ 1 to λ n , each of between the lens unit (13-2, 13-4, 13-6, 13-8) and the end face 14. By adjusting the distance, the optical fiber 303 can be made into a fan-in device having wavelength selectivity. Specifically, by setting the distance between the lens unit 13-2 and the end face 14 as the focal length of the lens unit 13-2 at the wavelength λ 1 , the signal light L1 emitted from the lens unit 13-2 has the wavelength λ. Only 1 will be incident on the core 21-1 of the multi-core fiber 52. Similarly, by setting the distance between the lens unit 13-k (k is an even number) and the end face 14 as the focal length at the wavelength λ j (j is an integer from 1 to n) of the lens unit 13-k, the lens unit As for the signal light L1 emitted from 13-k, only the wavelength λ j is incident on the core 21-j of the multi-core fiber 52. However, signal light L1 having a plurality of wavelengths (λ 1 to λ n ) is incident on the core 21-j of the multi-core optical fiber 52 that is directly connected to the core 11 of the optical fiber 303.
（実施形態４）
　図４は、本実施形態の光ファイバ３０４を説明する図である。光ファイバ３０４は、コアが１つであり、少なくとも１つのレンズ部と接触している。図４の光ファイバ３０４は、１つのコア１１とコア１１上に形成された１つのレンズ部１３を有している。光ファイバ３０４は、モードフィールド径を変換する。 (Embodiment 4)
FIG. 4 is a diagram illustrating the optical fiber 304 of the present embodiment. The optical fiber 304 has one core and is in contact with at least one lens portion. The optical fiber 304 of FIG. 4 has one core 11 and one lens unit 13 formed on the core 11. The optical fiber 304 converts the mode field diameter.
　光ファイバ３０４の端面１４には、単一コア光ファイバ５３が接続される。単一コア光ファイバ５３のコア２５のモードフィールド径（ＭＦＤ＝ａ２）は、コア１１のモードフィールド径（ＭＦＤ＝ａ１）と異なる。ＭＦＤの異なる光ファイバを接続すると、ＭＦＤ不整合により接続損失が発生する。本実施形態では、レンズ部１３が、ＭＦＤ＝ａ１のコア１１を伝搬する信号光Ｌ１をコア２５のＭＦＤ＝ａ２に拡大し、コア２５に入射する。図４では、光ファイバ５３のコア２５のＭＦＤの方が大きい場合を説明したが、コア２５のＭＦＤの方が小さい場合でもよい。この場合、レンズ部１３は、信号光Ｌ１を集光する。このように、光ファイバ３０４を使用することで異なるＭＦＤの光ファイバを低損失で接続することができる。 A single core optical fiber 53 is connected to the end face 14 of the optical fiber 304. The mode field diameter (MFD = a 2 ) of the core 25 of the single core optical fiber 53 is different from the mode field diameter (MFD = a 1 ) of the core 11. When optical fibers with different MFDs are connected, connection loss occurs due to MFD inconsistency. In the present embodiment, the lens unit 13 expands the signal light L1 propagating through the core 11 of the MFD = a1 to the MFD = a2 of the core 25 and incidents on the core 25. In FIG. 4, the case where the MFD of the core 25 of the optical fiber 53 is larger has been described, but the case where the MFD of the core 25 is smaller may be used. In this case, the lens unit 13 collects the signal light L1. In this way, by using the optical fiber 304, it is possible to connect optical fibers of different MFDs with low loss.
（実施形態５）
　本実施形態では、実施形態１から４で説明した光ファイバ（３０１～３０４）を用いたファンイン・ファンアウトデバイスやパワースプリッタの省スペース化技術について説明する。 (Embodiment 5)
In this embodiment, a space-saving technique for a fan-in / fan-out device and a power splitter using the optical fibers (301 to 304) described in the first to fourth embodiments will be described.
　一般的に同一の構造を有したレンズではレンズ境界の屈折率差が大きいほど焦点距離が短くなる。実施形態２で説明したフェムト秒パルスレーザで形成したレンズ部は石英ガラス構造を変質させて屈折率を変化させたものであり、レンズ境界の屈折率差は限定的である。そのため、レンズの焦点距離を短くすることが難しい。そこで、高強度フェムト秒パルスレーザで空孔を付与する。レンズ部１３を空孔で形成することでレンズ境界の屈折率差を大きくすることができる。レンズ部１３を空孔とすることで短い焦点距離とすることができ、光ファイバ（３０１～３０４）の長さを短くし、ファンイン・ファンアウトデバイスやパワースプリッタの省スペース化を実現できる。 Generally, for lenses having the same structure, the larger the difference in refractive index at the lens boundary, the shorter the focal length. The lens portion formed by the femtosecond pulse laser described in the second embodiment is obtained by altering the quartz glass structure to change the refractive index, and the difference in the refractive index at the lens boundary is limited. Therefore, it is difficult to shorten the focal length of the lens. Therefore, a hole is provided by a high-intensity femtosecond pulse laser. By forming the lens portion 13 with holes, the difference in the refractive index at the lens boundary can be increased. By making the lens portion 13 a hole, a short focal length can be obtained, the length of the optical fiber (301 to 304) can be shortened, and space saving of a fan-in / fan-out device or a power splitter can be realized.
（実施形態６）
　本実施形態では、光ファイバ（３０１～３０４）と、前記光ファイバのレンズ部を介する光を伝搬する伝搬光ファイバと、を備える光伝送路を説明する。 (Embodiment 6)
In this embodiment, an optical transmission line including an optical fiber (301 to 304) and a propagation optical fiber that propagates light through a lens portion of the optical fiber will be described.
　図５は、本実施形態の光伝送路４０１を説明する図である。光伝送路４０１は、ＭＦＤの異なる光ファイバを接続して構成した通信システムである。光伝送路４０１は、実施形態４で説明した光ファイバ３０４を備える。送信機４１及び受信機４２側の光ファイバ３０４のＭＦＤ＝ａ１と伝送路である単一コア光ファイバ５３のコア２５のＭＦＤ＝ａ２とが異なっている。 FIG. 5 is a diagram illustrating an optical transmission line 401 of the present embodiment. The optical transmission line 401 is a communication system configured by connecting optical fibers having different MFDs. The optical transmission line 401 includes the optical fiber 304 described in the fourth embodiment. The MFD = a1 of the optical fiber 304 on the transmitter 41 and the receiver 42 side and the MFD = a2 of the core 25 of the single core optical fiber 53 which is the transmission line are different.
　送信機４１から送出された信号光Ｌ１は光ファイバ３０４－１のレンズ部１３でＭＦＤがａ１からａ２に変換され、伝送路５３に入射される。伝送路５３を伝搬した信号光Ｌ１は光ファイバ３０４－２のレンズ部１３でＭＦＤがａ２からａ１に変換され、受信機４２にて受信される。光伝送路４０１は、上記構成によりＭＦＤ不整合による光損失を抑制することができる。 The signal light L1 transmitted from the transmitter 41 has an MFD converted from a1 to a2 by the lens unit 13 of the optical fiber 304-1 and is incident on the transmission line 53. The signal light L1 propagating through the transmission path 53 has an MFD converted from a 2 to a 1 by the lens unit 13 of the optical fiber 304-2, and is received by the receiver 42. The optical transmission line 401 can suppress optical loss due to MFD mismatch due to the above configuration.
　図６は、本実施形態の光伝送路４０２を説明する図である。光伝送路４０２は、空間分割多重伝送路の通信システムである。光伝送路４０２は、複数の送信機４１、複数の受信機４２、空間分割多重伝送路５５、及び実施形態２で説明した光ファイバ３０２を備える。本実施形態は、実施形態２で説明した光ファイバ３０２をファンイン・ファンアウトデバイスやパワースプリッタとして空間分割多重伝送路の入出力デバイスとして用いている。 FIG. 6 is a diagram illustrating the optical transmission line 402 of the present embodiment. The optical transmission line 402 is a communication system of a space division multiplex transmission line. The optical transmission line 402 includes a plurality of transmitters 41, a plurality of receivers 42, a space division multiplex transmission line 55, and an optical fiber 302 described in the second embodiment. In this embodiment, the optical fiber 302 described in the second embodiment is used as a fan-in / fan-out device or a power splitter as an input / output device of a space-divided multiplex transmission line.
　送信機４１（１～Ｎ）からの信号光は光ファイバ３０２－１に入射される。光ファイバ３０２－１は空間分割多重伝送路５５（例えばマルチコア光ファイバ）に接続され、各信号光は空間分割多重伝送路５５の各光路（各コア）に入射される。空間分割多重伝送路５５を伝搬してきた信号光は光ファイバ３０２－２で各空間チャネルから取り出され、受信機４２（１～Ｎ）にて受信される。 The signal light from the transmitters 41 (1 to N) is incident on the optical fiber 302-1. The optical fiber 302-1 is connected to a space-divided multiplex transmission line 55 (for example, a multi-core optical fiber), and each signal light is incident on each optical path (each core) of the space-divided multiplex transmission line 55. The signal light propagating through the space division multiplexing transmission line 55 is taken out from each space channel by the optical fiber 302-2 and received by the receivers 42 (1 to N).
　光伝送路４０２は、上記構成により、従来の空間光学系を用いた空間分割多重伝送システムと比較して、低コスト化および送受信端の省スペース化ができる。 With the above configuration, the optical transmission line 402 can be reduced in cost and space at the transmission / reception end as compared with a time division multiplexing transmission system using a conventional space optical system.
　本発明は、光通信網の保守に用いることができる。 The present invention can be used for maintenance of an optical communication network.
１１、１１－１、１１－２、・・・、１１－ｍ：コア
１２：クラッド
１３、１３－１、１３－２、・・・、１３－ｍ：レンズ部
１４：端面
２１－１、２１－２、・・・、２１－ｎ：レンズ部
２５：コア
４１：送信機
４２：受信機
５１、５１－１、５１－２、・・・、５１－ｍ：
５２：マルチコア光ファイバ
５３：単一コア光ファイバ
５５：空間分割多重伝送路
３０１、３０２、３０３、３０４：光ファイバ
４０１、４０２：光伝送路 11, 11-1, 11-2, ..., 11-m: Core 12: Clad 13, 13-1, 13-2, ..., 13-m: Lens unit 14: End faces 21-1, 21 -2, ..., 21-n: Lens unit 25: Core 41: Transmitter 42: Receivers 51, 51-1, 51-2, ..., 51-m:
52: Multi-core optical fiber 53: Single-core optical fiber 55: Spatial division multiple transmission line 301, 302, 303, 304: Optical fiber 401, 402: Optical transmission line

Claims (7)

  1. 　コアを伝搬する光に対してレンズの機能を持つレンズ部を備える光ファイバ。 An optical fiber equipped with a lens unit that functions as a lens for light propagating in the core.
  2. 　前記コアは１つであり、少なくとも１つの前記レンズ部と接触している
    ことを特徴とする請求項１に記載の光ファイバ。     The optical fiber according to claim 1, wherein the core is one and is in contact with at least one lens portion.
  3. 　前記コアは複数であり、
    　前記コアのそれぞれは少なくとも１つの前記レンズ部と接触している
    ことを特徴とする請求項１に記載の光ファイバ。     There are multiple cores,
    The optical fiber according to claim 1, wherein each of the cores is in contact with at least one lens portion.
  4. 　前記コアに接触していない前記レンズ部は、前記コアに接触している前記レンズ部からの光を受ける位置に配置されていることを特徴とする請求項１から３のいずれかに記載の光ファイバ。 The light according to any one of claims 1 to 3, wherein the lens portion that is not in contact with the core is arranged at a position that receives light from the lens portion that is in contact with the core. fiber.
  5. 　前記レンズ部は、前記コアより屈折率が大きいことを特徴とする請求項１から４のいずれかに記載の光ファイバ。 The optical fiber according to any one of claims 1 to 4, wherein the lens portion has a higher refractive index than the core.
  6. 　前記レンズ部は、空洞であることを特徴とする請求項１から４のいずれかに記載の光ファイバ。 The optical fiber according to any one of claims 1 to 4, wherein the lens portion is hollow.
  7. 　請求項１から６のいずれかに記載の光ファイバと、
    　前記光ファイバの前記レンズ部を介する光を伝搬する伝搬光ファイバと、
    を備える光伝送路。     The optical fiber according to any one of claims 1 to 6 and
    A propagating optical fiber that propagates light through the lens portion of the optical fiber,
    An optical transmission line.
PCT/JP2020/032293 2020-08-27 2020-08-27 Optical fiber and optical transmission line WO2022044181A1 (en)

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PCT/JP2020/032293 WO2022044181A1 (en) 2020-08-27 2020-08-27 Optical fiber and optical transmission line

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JP2001332788A (en) * 2000-05-23 2001-11-30 Mitsubishi Electric Corp Optical fiber for amplification
JP2004138720A (en) * 2002-10-16 2004-05-13 Hitachi Cable Ltd Optical component and its manufacturing method
JP2005292382A (en) * 2004-03-31 2005-10-20 Kazuyuki Hirao Optical element, method for manufacturing the same and optical device
KR20080029598A (en) * 2006-09-29 2008-04-03 한국전자통신연구원 Optical fiber having diffraction grating, method of fabricating diffraction grating at cutting plane, and optical apparatus using the same fiber
JP2013506866A (en) * 2009-09-30 2013-02-28 コーニング インコーポレイテッド Optical fiber end structure and related systems and methods for improving multimode bandwidth
JP2014081588A (en) * 2012-10-18 2014-05-08 Fuji Xerox Co Ltd Optical transmission system, optical transmission line, and manufacturing method of optical transmission line
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JPH02306206A (en) * 1989-05-22 1990-12-19 Kenji Machida Optical fiber having recessed curved surface or projecting curved surface on edge surface
JP2001332788A (en) * 2000-05-23 2001-11-30 Mitsubishi Electric Corp Optical fiber for amplification
JP2004138720A (en) * 2002-10-16 2004-05-13 Hitachi Cable Ltd Optical component and its manufacturing method
JP2005292382A (en) * 2004-03-31 2005-10-20 Kazuyuki Hirao Optical element, method for manufacturing the same and optical device
KR20080029598A (en) * 2006-09-29 2008-04-03 한국전자통신연구원 Optical fiber having diffraction grating, method of fabricating diffraction grating at cutting plane, and optical apparatus using the same fiber
JP2013506866A (en) * 2009-09-30 2013-02-28 コーニング インコーポレイテッド Optical fiber end structure and related systems and methods for improving multimode bandwidth
JP2014081588A (en) * 2012-10-18 2014-05-08 Fuji Xerox Co Ltd Optical transmission system, optical transmission line, and manufacturing method of optical transmission line
JP2014178628A (en) * 2013-03-15 2014-09-25 Hitachi Ltd Fan-in/fan-out device for multiple core fiber connection, optical connection device, and optical connection method
US20180281324A1 (en) * 2015-10-07 2018-10-04 Baden-Württemberg Stiftung Ggmbh Method and device for producing microstructures on optical fibers

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