WO2024166205A1 - 光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法 - Google Patents

光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法 Download PDF

Info

Publication number
WO2024166205A1
WO2024166205A1 PCT/JP2023/003982 JP2023003982W WO2024166205A1 WO 2024166205 A1 WO2024166205 A1 WO 2024166205A1 JP 2023003982 W JP2023003982 W JP 2023003982W WO 2024166205 A1 WO2024166205 A1 WO 2024166205A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical fiber
optical
polishing
polishing surface
polished surface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2023/003982
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
卓威 植松
一貴 納戸
幾太郎 大串
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP2024575909A priority Critical patent/JPWO2024166205A1/ja
Priority to PCT/JP2023/003982 priority patent/WO2024166205A1/ja
Publication of WO2024166205A1 publication Critical patent/WO2024166205A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • 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
    • 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
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals

Definitions

  • This disclosure relates to an optical fiber coupler, a method for manufacturing an optical fiber coupler, and an optical multiplexing/demultiplexing method.
  • Non-Patent Document 1 is a document related to this technology, and examines a method of polishing the side surface of optical fiber.
  • optical fibers are regulated by international standards and other regulations. However, even if an optical fiber meets these regulations, its internal refractive index distribution will vary due to manufacturing errors and the manufacturer. In other words, the propagation constant of propagating light between optical fibers will vary within the range of the standards. This variation in the propagation constant will cause the coupling efficiency of an optical fiber coupler that uses that optical fiber to fluctuate and in some cases may even decrease.
  • This disclosure has been made in consideration of the above circumstances, and aims to provide an optical fiber coupler that can branch and join optical fibers having various propagation constants with a desired coupling efficiency, a method for manufacturing an optical fiber coupler, and an optical multiplexing/demultiplexing method.
  • An optical fiber coupler comprises a first optical fiber including a first polished surface formed on a side surface thereof, and a second optical fiber including a second polished surface formed on a side surface thereof and in contact with the first polished surface, and the distance between the second polished surface and the central axis of the second optical fiber changes continuously along the longitudinal direction of the second optical fiber so as to continuously change the propagation constant of the second optical fiber.
  • a method for manufacturing an optical fiber coupler includes bringing a first polished surface formed on a side of a first optical fiber and a second polished surface formed on a side of a second optical fiber into sliding contact with each other, moving one of the first polished surface and the second polished surface relative to the other until a predetermined coupling efficiency is obtained, thereby maintaining the relative positions of the first polished surface and the second polished surface, and the distance between the second polished surface and the central axis of the second optical fiber is continuously changed along the longitudinal direction of the second optical fiber so as to continuously change the propagation constant of the second optical fiber.
  • a first polished surface formed on a side of a first optical fiber and a second polished surface formed on a side of a second optical fiber are brought into sliding contact with each other, and one of the first polished surface and the second polished surface is moved relative to the other until a predetermined coupling efficiency is obtained, thereby maintaining the relative positions of the first polished surface and the second polished surface, and the distance between the second polished surface and the central axis of the second optical fiber is continuously changed along the longitudinal direction of the second optical fiber so that the propagation constant of the second optical fiber is continuously changed.
  • the present disclosure provides an optical fiber coupler that can split and join optical fibers having various propagation constants with a desired coupling efficiency, a method for manufacturing an optical fiber coupler, and an optical multiplexing/demultiplexing method.
  • FIG. 1 is a cross-sectional view illustrating an example of an optical fiber coupler according to an embodiment of the present disclosure.
  • FIG. 2 is a cross-sectional view taken along line AA in FIG.
  • FIG. 3A is an enlarged cross-sectional view showing a polished surface formed on the optical fiber according to the present embodiment.
  • FIG. 3B is an enlarged cross-sectional view showing the polished surface formed on the optical fiber according to the present embodiment.
  • FIG. 4 is a graph showing the dependence of the propagation constant ⁇ and the propagation loss of the optical fiber according to this embodiment on the amount of polishing t.
  • FIG. 1 is a cross-sectional view illustrating an example of an optical fiber coupler according to an embodiment of the present disclosure.
  • FIG. 2 is a cross-sectional view taken along line AA in FIG.
  • FIG. 3A is an enlarged cross-sectional view showing a polished surface formed on the optical fiber according to the present embodiment.
  • FIG. 3B is an enlarged cross-sectional view showing the
  • FIG. 5 is a graph showing the change in the propagation constant ⁇ and the amount of polishing t along the Z direction when the maximum amount of polishing t of the core according to this embodiment is set to 6 ⁇ m.
  • FIG. 6 is a graph showing the dependence of the coupling efficiency between two optical fibers on the propagation constant difference ⁇ .
  • FIG. 7 is a graph showing the dependence of the polishing loss of an optical fiber on the remaining cladding thickness d lv .
  • FIG. 8A is a perspective view showing an example of a polishing apparatus used to form a polished surface.
  • FIG. 8B is a cross-sectional view of the holder shown in FIG. 8A.
  • FIG. 9 is a perspective view showing an example of the configuration of the position adjustment device 40. As shown in FIG.
  • optical fiber coupler a method for manufacturing an optical fiber coupler, and an optical multiplexing/demultiplexing method according to an embodiment of the present disclosure. Note that common parts in each figure are given the same reference numerals, and duplicated explanations will be omitted.
  • optical fibers that have already been installed in a network are called current optical fibers.
  • Current optical fibers are installed in facilities that build a network, such as utility tunnels and overhead lines. They may be installed either indoors or outdoors. Current optical fibers may already be used for optical communications in the network, or may be installed and unused.
  • Optical fibers that are newly connected to current optical fibers are called branch fibers. Branch fibers are optical fibers that branch off from a route (transmission route) built by the current optical fiber, or that build a route that merges into that route.
  • the X, Y, and Z directions are defined as being orthogonal to each other.
  • the X and Z directions are the directions in which one of the two holding parts 41, 42 (see FIG. 8A) according to this embodiment moves relative to the other.
  • the Y direction is the arrangement direction of the two holding parts 41, 42.
  • the Z direction is also the longitudinal direction (extension direction) of the two optical fibers 10, 20 and the extension direction of the V-groove 34 formed in each holding part 41 (42).
  • the radial direction R is the radial direction of each optical fiber 10, 20.
  • Fig. 1 is a cross-sectional view of the optical fiber coupler 1 including the central axes 10a, 20a of the two optical fibers 10, 20.
  • Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1.
  • Fig. 2 shows the optical fiber 10 held by the holding portion 41, and the optical fiber 20 held by the holding portion 42.
  • the optical fiber coupler 1 includes an optical fiber (first optical fiber) 10 and an optical fiber (second optical fiber) 20.
  • the cross-sectional view shown in FIG. 1 is parallel to the YZ plane and includes the central axis 10a of the optical fiber 10 and the central axis 20a of the optical fiber 20.
  • the optical fiber 10 is, for example, the above-mentioned currently used optical fiber, and has already been laid in a network (not shown).
  • the optical fiber 10 has a core (first core) 11, a cladding (first cladding) 12, and a coating (first coating) 13.
  • the optical fiber 10 is a single-mode optical fiber or a multimode optical fiber.
  • the optical fiber 20 is, for example, the branch fiber described above, and is newly connected to the optical fiber 10 as an additional path of a network (not shown).
  • the optical fiber 20 has a core (second core) 21, a cladding (second cladding) 22, and a coating (second coating) 23.
  • the optical fiber 20 is also a single-mode optical fiber or a multimode optical fiber.
  • the optical fiber 10 has a polished surface (first polished surface) 14 on a side surface 15.
  • the polished surface 14 is formed by polishing the side surface 15. This polishing process can be performed, for example, by a polishing device 30 (see FIGS. 8A and 8B ) described below. This polishing process removes the coating 13, leaving a portion of the cladding 12, and forms the polished surface 14.
  • the thickness of the cladding 12 from the polished surface 14 to the core 11 is defined as a remaining cladding thickness d lv (see FIG. 3A ).
  • optical fiber 20 has a polished surface (second polished surface) 24 on side surface 25. Polished surface 24 is formed by polishing side surface 25. This polishing process can also be performed by polishing device 30, which will be described later.
  • the optical fiber 10 extends in the Z direction while being bent with a radius of curvature (first radius of curvature) R lv at least in a portion including the polished surface 14.
  • the polished surface 14 is formed by polishing a side surface 15 of the optical fiber 10 placed in a state in which the optical fiber 10 is bent with the radius of curvature R lv . Therefore, when the optical fiber 10 is bent with the radius of curvature R lv , the polished surface 14 forms an elliptical plane extending in the longitudinal direction of the optical fiber 10.
  • the optical fiber 20 extends in the Z direction while being bent with a radius of curvature (second radius of curvature) R br at least in a portion including the polished surface 24.
  • the polished surface 24 is formed by polishing a side surface 25 of the optical fiber 20 placed in a state in which the optical fiber 20 is bent with the radius of curvature R br . Therefore, when the optical fiber 20 is bent with the radius of curvature R br , the polished surface 24 forms an elliptical plane extending in the longitudinal direction of the optical fiber 20.
  • a refractive index matching agent (not shown) is interposed between polished surface 14 and polished surface 24.
  • the refractive index matching agent may be a viscous liquid or a deformable solid.
  • the refractive index of the refractive index matching agent is smaller than the refractive indexes of cladding 12 and cladding 22. This prevents an increase in insertion loss.
  • Polished surface 14 and polished surface 24 are in contact with each other via a refractive index matching agent (not shown). Therefore, core 11 and core 21 are positioned relative to each other with a core spacing d (see FIG. 1B). Core spacing d is the minimum spacing between core 11 and core 21.
  • evanescent coupling between core 11 and core 21 is obtained. That is, core 11 and core 21 are optically coupled, enabling the multiplexing or demultiplexing of light, which is the function of optical fiber coupler 1.
  • the evanescent coupling becomes weaker as the difference in the propagation constants of the two optical fibers increases. In other words, as the difference in the propagation constants increases, the coupling efficiency of the optical fiber coupler decreases.
  • Fig. 3A is an enlarged cross-sectional view showing the polished surface 14 formed on the optical fiber 10.
  • Fig. 3B is an enlarged cross-sectional view showing the polished surface 24 formed on the optical fiber 20.
  • Fig. 3A shows the optical fiber 10 in a state where it has been released from bending with a radius of curvature R lv and is proceeding straight.
  • Fig. 3B shows the optical fiber 20 in a state where it has been released from bending with a radius of curvature R br and is proceeding straight.
  • a portion of the polished surface 14 is omitted in Fig. 3A.
  • a portion of the polished surface 24 is omitted in Fig. 3B.
  • the polished surface 14 is formed in a state where the optical fiber 10 is bent with a radius of curvature R lv . Therefore, as shown in Fig. 3A, when the optical fiber 10 is advanced in a straight line, the polished surface 14 becomes a curved surface in which the distance between the polished surface 14 and the central axis 10a changes continuously along the Z direction.
  • the part of this curved surface closest to the polished surface 24 i.e., the part where the remaining cladding thickness d lv is smallest, or the deepest part of the polished surface 14 corresponds to the apex of the bent optical fiber 10.
  • the polished surface 24 is formed in a state where the optical fiber 20 is bent with a radius of curvature R br . Therefore, as shown in Fig. 3B, when the optical fiber 20 advances in a straight line, the polished surface 24 becomes a curved surface in which the distance between the polished surface 24 and the central axis 20a changes continuously along the Z direction. The part of this curved surface closest to the polished surface 14 (i.e., the deepest part of the polished surface 24) corresponds to the apex of the bent optical fiber 20.
  • the distance D between the polishing surface 24 and the central axis 20a of the optical fiber 20 along the radial direction R changes continuously along the Z direction (i.e., the longitudinal direction of the second optical fiber) so as to continuously change the propagation constant of the optical fiber 20.
  • the propagation constant changes according to the change in the cross-sectional shape (cross-sectional area) of the core perpendicular to the Z direction.
  • the polishing surface 24 in this embodiment reaches the core 21, and the cross-sectional shape (outer shape) of the core 21 in the region S reached by the polishing surface 24 changes continuously along the Z direction.
  • the polishing amount t the maximum value of the distance (spacing) between the polished surface 24 and the boundary surface 26 between the core 21 and cladding 22 of the optical fiber 20 along the radial direction R.
  • the polished surface 24 is formed by polishing the bent portion of the optical fiber 20. Therefore, when the polishing amount t is defined for the core 21, this means that a tapered surface is formed as the polished surface 24 in the state shown in Figure 3B, where the distance between the polished surface 24 and the boundary surface 26 changes continuously from 0 to the polishing amount t.
  • Figure 4 is a graph showing the dependence of the propagation constant ⁇ and propagation loss of optical fiber 20 on the amount of polishing t.
  • the solid line indicates the propagation constant ⁇
  • the dashed line indicates the propagation loss.
  • this numerical analysis assumes that the radius a of core 21 is 4.5 ⁇ m, the wavelength of light traveling through core 21 is 1.31 ⁇ m, and the relative refractive index difference (core ⁇ ) between core 21 and cladding 22 is 0.42%.
  • the propagation constant ⁇ becomes smaller as the core is polished, and when the thickness of the core 21 is less than about 2 ⁇ m, it becomes approximately constant regardless of the value of the amount of polishing t. Also, as shown by the dashed line, when the amount of polishing t exceeds 6 ⁇ m, the propagation loss increases sharply.
  • Figure 5 is a graph showing the change in the propagation constant ⁇ and the amount of polishing t along the Z direction when the maximum amount of polishing t of the core 21 is set to 6 ⁇ m.
  • the solid line indicates the propagation constant ⁇
  • the dashed line indicates the amount of polishing t.
  • this numerical analysis also assumes that the radius a of the core 21 is 4.5 ⁇ m, the wavelength of the light traveling through the core 21 is 1.31 ⁇ m, and the relative refractive index difference ⁇ between the core 21 and the cladding 22 is 0.42%.
  • the propagation constant ⁇ is at a minimum close to the apex of the bend, and approaches its original value the further away from the apex it is.
  • the optical fiber 20 can be optically coupled to the optical fiber 10 with a propagation constant of 6.941 to 6.957.
  • the optical fiber 20 When the optical fiber 20 is a branched optical fiber and the optical fiber 10 is one of a plurality of optical fibers already laid in a network, the optical fiber 20 may have a propagation constant equal to or greater than the maximum propagation constant of the plurality of optical fibers including the optical fiber 10.
  • the optical fiber 20 it is desirable for the optical fiber 20 to have a V value (V parameter) of 3 or more.
  • V parameter V parameter
  • the optical fiber 20 has a step-index type refractive index distribution, the radius of the core 21 is 4.5 ⁇ m, and the relative refractive index difference is 0.42%.
  • the optical fiber 20 having the above characteristics, when the polishing amount t is set to 6 ⁇ m, a lower limit of the V value is obtained that is close to 1.5.
  • the optical fiber 20 is compatible with all currently used optical fibers (i.e., optical fibers 10) that comply with ITU-T G.652 and G.657.A1. In other words, optical coupling with high coupling efficiency can be obtained with all commonly used single-mode optical fibers.
  • Figure 6 is a graph showing the dependence of the coupling efficiency (branching efficiency) between optical fibers 10 and 20 on the propagation constant difference ⁇ .
  • the solid line shows the change in coupling efficiency when the polishing amount t of the core 21 is 6 ⁇ m
  • the dashed line shows the change in coupling efficiency when the core 21 is not polished (i.e., the polishing amount t is 0).
  • the open and closed circles show the coupling coefficient when optical fiber 20 is optically coupled to each of the samples of optical fiber 10 with different propagation constants. However, the open circles show the coupling coefficient when the polishing amount t of the core 21 is 6 ⁇ m, and the closed circles show the coupling coefficient when the core 21 is not polished.
  • optical fiber 10 is an optical fiber in use, communication light is constantly propagating through the optical fiber 10. Therefore, side polishing of the optical fiber 10 must be performed without affecting the optical communication through the optical fiber 10.
  • Fig. 7 is a graph showing the dependence of the polishing loss of the optical fiber 10 on the remaining cladding thickness d lv . Note that the numerical analysis shown in this graph assumes the sample optical fiber 10 used in the numerical analysis of Fig. 6. In other words, a plurality of optical fibers 10 with different propagation constants are assumed.
  • the remaining cladding thickness d lv required to obtain the maximum coupling efficiency in each sample in FIG. 6 was all about 1 ⁇ m. Therefore, it is desirable to set the target value of the polishing loss in the optical fiber 10 to about 0.2 dB. Also, considering the influence of the polishing loss on currently used optical communications, the polishing loss should be 0.5 dB or less. This value is about the same as the connection loss due to an optical connector. If the requirement for coupling efficiency is low, the remaining cladding thickness d lv may be even larger, and for example, the polishing loss should be 0.1 dB or more.
  • the propagation constant of at least one of the multiple optical fibers constituting the optical fiber coupler changes continuously within a certain range along the Z direction. Therefore, even if there is variation in the propagation constant of the optical fiber that is the other end of the optical coupling, it is possible to achieve optical coupling that matches the propagation constant of the optical fiber that is the other end of the optical coupling with a propagation constant that is equal to or close to the propagation constant. In other words, other optical fibers can be branched and merged with the desired coupling efficiency for optical fibers having various propagation constants.
  • the above-mentioned polishing surface that continuously changes the propagation constant is formed on at least one of the optical fibers 10 and 20.
  • FIG. 8A is a perspective view showing an example of a polishing device 30 used to form the polishing surface 14 (24).
  • FIG. 8B is a cross-sectional view of the holding part 32 shown in FIG. 8A.
  • the polishing device 30 includes a polishing table 31 and a holding part 32.
  • the formation of the polishing surface 14 will be described as an example.
  • the polishing table 31 has a flat upper surface 31a, on which a polishing sheet 33 is placed.
  • the holding part 32 has a flat surface 32a facing the upper surface 31a of the polishing table 31, and a V-shaped groove 34 curved with a radius R is formed on the flat surface 32a.
  • the radius R is slightly smaller than the radius of curvature Rlv .
  • the material of the polishing table 31 and the holding part 32 is, for example, glass.
  • the V-groove 34 is formed so that its depth from the plane 32a is shallowest near the center of the plane 32a, and as shown in Fig. 8B, the minimum depth of the V-groove 34 is set to a value that allows the cladding 12 to have a remaining cladding thickness d lv .
  • the polishing process of the optical fiber 10 using the polishing device 30 is performed at the site where the optical fiber 20 is connected to the optical fiber 10.
  • a state is prepared for measuring the leaked light from the optical fiber 10. Specifically, the optical fiber 10 is bent while laser light (for convenience, referred to as propagating light) is propagating through the optical fiber 10, and the intensity of the laser light (for convenience, referred to as leaked light) leaking from the bent portion is measured with a light intensity meter (not shown).
  • the optical fiber 10 is an optical fiber in use. Therefore, the light propagating through the optical fiber 10 is communication light propagating through the network or pseudo communication light introduced using a specified light source. In either case, a bend that causes a loss that does not affect communication is imparted to the optical fiber 10, and the intensity of the leaked light from the bent portion is measured until polishing is completed.
  • adhesive 35 (see FIG. 2) is filled into the V-groove 34 of the holding portion 32, and the optical fiber 10 is fixed in the V-groove 34.
  • the adhesive 35 hardens and the optical fiber 10 is fixed in the V-groove 34, a part of the side surface 15 of the optical fiber 10 is exposed from the flat surface 32a of the holding portion 32 (see FIG. 8B).
  • the flat surface 32a of the holding portion 32 is opposed to the polishing sheet 33 placed on the polishing table 31. After that, the side surface 15 of the optical fiber 10 exposed from the flat surface 32a of the holding portion 32 is pressed against the polishing sheet 33 and polished.
  • the polishing of the side surface 15 is performed while monitoring the intensity of the leaking communication light. As the polishing progresses, the polished surface approaches the core 11 (i.e., the remaining cladding thickness d lv decreases), and the intensity of the leaking light being measured gradually decreases. Then, when the intensity of the leaking light reaches a predetermined value, the polishing is stopped and the bend is released. Through this series of steps, the formation of the polished surface 14 is completed.
  • the polished surface 24 of the optical fiber 20 is also formed through a process similar to that described above.
  • the polished surface 24 may be formed in advance at a remote location such as a factory. In this case, more precise processing is possible than on-site processing.
  • a method for manufacturing the optical fiber coupler 1 and a method for optical multiplexing/demultiplexing will be described.
  • the relative positions of the optical fiber 10 and the optical fiber 20 i.e., the polished surface 14 and the polished surface 24
  • a position adjustment device 40 i.e., the relative positions of the optical fiber 10 and the optical fiber 20 (i.e., the polished surface 14 and the polished surface 24) are adjusted using a position adjustment device 40.
  • Fig. 9 is a perspective view showing an example of the configuration of the position adjustment device 40.
  • the position adjustment device 40 includes a holder 41, a holder 42, a light source 43, a light intensity meter 44, and a stage 45.
  • the holding portion 41 is the same as the holding portion 32 (see FIG. 8A ) that holds the optical fiber 10.
  • the holding portion 42 is the same as the holding portion 32 that holds the optical fiber 20. That is, the holding portion 41 is the holding portion 32 in which the V-groove 34 having a radius R slightly smaller than the radius of curvature R lv is formed, and the holding portion 42 is the holding portion 32 in which the V-groove 34 having a radius R slightly smaller than the radius of curvature R br is formed.
  • the holding portions 41 and 42 hold the corresponding optical fibers with the polishing surfaces 14 and 24 in slidable contact with each other.
  • the holding unit 41 holds the optical fiber 10 after the above-mentioned polishing process has been completed. That is, the holding unit 41 holds the optical fiber 10 with the polished surface 14 exposed on the plane 41a.
  • the plane 41a is parallel to the XZ plane.
  • the holding unit 42 holds the optical fiber 10 with the polished surface 24 exposed on the plane 42a.
  • the plane 42a is also parallel to the XZ plane.
  • the holding parts 41 and 42 hold the corresponding optical fibers with the polishing surfaces 14 and 24 in slidable contact with each other.
  • the holding parts 41 and 42 are lined up in the Y direction with their respective flat surfaces 41a and 42a in slidable contact with each other.
  • the holding part 42 is placed on the upper surface 45a of the stage 45, and the holding part 41 is stacked on the holding part 42.
  • the light source 43 is a laser light source having a known configuration, and generates test light 80 that is incident on the optical fiber 20.
  • the test light 80 may be incident on either end of the optical fiber 20.
  • the light source 43 is connected to the end of the optical fiber 20 (i.e., the branch fiber) located on the opposite side of the optical fiber coupler 1 from the optical network unit (ONU) on the telecommunications carrier side that connects to the optical fiber 10.
  • the optical intensity meter 44 receives the test light 80 that has passed through the optical fiber 20, measures the intensity of the test light 80, and outputs the measurement value to a monitor (not shown) or the like.
  • the stage 45 has an upper surface 45a parallel to the XZ plane and is arranged to be slidable in the Z direction.
  • the linear actuator 46 is connected to the stage 45 and moves the stage 45 in the Z direction.
  • the stage 45 may be arranged to be slidable in the X direction as well as the Z direction.
  • the desired coupling efficiency of the optical fiber coupler 1 can be obtained by using the position adjustment device 40 through the following procedure. That is, first, the holding part 42 is placed on the upper surface 45a of the stage 45. Furthermore, the holding part 41 is placed on the holding part 42. However, the movement of the holding part 41 is restricted by a jig (not shown).
  • a liquid refractive index matching agent (not shown) is applied to one of polished surfaces 14 and 24.
  • the refractive index matching agent may also be a solid.
  • the refractive index matching agent (not shown) is inserted between polished surface 14 and polished surface 24 and is sandwiched between the two polished surfaces.
  • the polished surface 14 and the polished surface 24 are brought into slidable contact with each other via a refractive index matching agent (not shown).
  • the optical fiber 10 maintains a state in which it is bent with a radius of curvature R lv at least in a portion including the polished surface 14.
  • the optical fiber 20 maintains a state in which it is bent with a radius of curvature R br at least in a portion including the polished surface 24.
  • Test light 80 having a preset intensity P in is input to the optical fiber 20.
  • the test light 80 propagates through the optical fiber 20 and is input to the optical power meter 44.
  • the optical power meter 44 measures the intensity P th of the input test light 80.
  • the coupling efficiency can be estimated using a formula expressed as 1-(P th /P in ). Note that communication light 81 (see FIG. 3C ) may or may not propagate through the optical fiber 10.
  • the stage 45 is moved in the Z direction.
  • the holder 41 also moves in the Z direction.
  • the movement of the holder 42 is regulated by a jig (not shown). Therefore, the holder 41 moves in the Z direction relative to the holder 42. Due to the relative movement of the holder 41 with respect to the holder 42, the polished surface 24 moves in the Z direction relative to the polished surface 14. Therefore, the propagation constant difference ⁇ between the optical fibers 10 and 20 changes, and the coupling efficiency (branching efficiency) increases or decreases.
  • the stage 45 is moved in the Z direction while monitoring the change in intensity Pth of the test light 80.
  • the intensity Pth reaches a reference value Prf corresponding to the desired coupling efficiency
  • the movement of the stage 45 is stopped, and the relative positions of the holders 41 and 42 at that time are maintained. That is, the relative positions of the polished surfaces 14 and 24 are maintained.
  • This relative position can be maintained by, for example, joining the holders 41 and 42 with an adhesive. In this way, an optical fiber coupler 1 having the desired coupling efficiency (i.e., an optical multiplexing/demultiplexing method) is obtained.
  • Optical fiber coupler 10 Optical fiber (first optical fiber) 11 core (first core) 12 Clad (first clad) 13 Coating (first coating) 14 Polished surface (first polished surface) 15 Side surface 20 Optical fiber (second optical fiber) 21 core (second core) 22 Clad (second clad) 23 Coating (second coating) 24 Polished surface (second polished surface) 25 Side surface 30 Polishing device 32 Holding portion 34 V-groove 35 Adhesive 40 Position adjustment device 41 Holding portion (first holding portion) 42 Holding part (second holding part) 43 Light source 44 Light intensity meter 45 Stage 46 Linear actuator

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Couplings Of Light Guides (AREA)
PCT/JP2023/003982 2023-02-07 2023-02-07 光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法 Ceased WO2024166205A1 (ja)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2024575909A JPWO2024166205A1 (cs) 2023-02-07 2023-02-07
PCT/JP2023/003982 WO2024166205A1 (ja) 2023-02-07 2023-02-07 光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2023/003982 WO2024166205A1 (ja) 2023-02-07 2023-02-07 光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法

Publications (1)

Publication Number Publication Date
WO2024166205A1 true WO2024166205A1 (ja) 2024-08-15

Family

ID=92262151

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/003982 Ceased WO2024166205A1 (ja) 2023-02-07 2023-02-07 光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法

Country Status (2)

Country Link
JP (1) JPWO2024166205A1 (cs)
WO (1) WO2024166205A1 (cs)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4302071A (en) * 1978-12-13 1981-11-24 Siemens Aktiengesellschaft Adjustable directional coupler for light waveguides
JPS60500030A (ja) * 1982-11-12 1985-01-10 ザ・ボ−ド・オブ・トラスティ−ズ・オブ・ザ・レランド・スタンフォ−ド・ジュニア・ユニバ−シティ ファイバ光学スイッチおよび離散的可変遅延線
US6968103B1 (en) * 2002-10-10 2005-11-22 General Dynamics Advanced Information Systems, Inc. Optical fiber coupler and method for making same
WO2021064916A1 (ja) * 2019-10-02 2021-04-08 日本電信電話株式会社 光分岐回路作製方法及び光分岐回路作製装置
WO2021166262A1 (ja) * 2020-02-21 2021-08-26 日本電信電話株式会社 光合分波方法、光合分波回路及び光合分波回路製造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4302071A (en) * 1978-12-13 1981-11-24 Siemens Aktiengesellschaft Adjustable directional coupler for light waveguides
JPS60500030A (ja) * 1982-11-12 1985-01-10 ザ・ボ−ド・オブ・トラスティ−ズ・オブ・ザ・レランド・スタンフォ−ド・ジュニア・ユニバ−シティ ファイバ光学スイッチおよび離散的可変遅延線
US6968103B1 (en) * 2002-10-10 2005-11-22 General Dynamics Advanced Information Systems, Inc. Optical fiber coupler and method for making same
WO2021064916A1 (ja) * 2019-10-02 2021-04-08 日本電信電話株式会社 光分岐回路作製方法及び光分岐回路作製装置
WO2021166262A1 (ja) * 2020-02-21 2021-08-26 日本電信電話株式会社 光合分波方法、光合分波回路及び光合分波回路製造方法

Also Published As

Publication number Publication date
JPWO2024166205A1 (cs) 2024-08-15

Similar Documents

Publication Publication Date Title
Li et al. Silica-based optical integrated circuits
Al-Azzawi Fiber optics: principles and advanced practices
JP7310906B2 (ja) 光分岐回路作製方法及び光分岐回路作製装置
US10007073B2 (en) Optical component including a high-relative-refractive-index-index-difference optical fiber a single-mode optical fiber an optical device and a fixing member to fix a relative opsition
US11333828B2 (en) Optical connection component
JP5856823B2 (ja) 光ファイバカプリング方法
JP7487810B2 (ja) 光接続構造
US12442987B2 (en) Branch ratio measuring device, branch ratio measuring method, and optical multiplexing/demultiplexing circuit manufacturing method
JP6438374B2 (ja) 光ファイバ側方入出力器及び光ファイバ側方入出力方法
US10048441B1 (en) Variable optical splitter system
WO2024166205A1 (ja) 光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法
Wang et al. A robust strategy for realizing highly-efficient passive alignment of fiber ribbons to integrated polymer waveguides
Oda et al. Spot size converting fiber with a 4-pm mode field diameter for low-loss coupling to silicon photonic circuits
Uematsu et al. Optical coupling technique based on fiber side-polishing without service interruption
WO2024111125A1 (ja) 光ファイバ位置調整装置及び光ファイバ位置調整方法
WO2024111122A1 (ja) 光分岐率調整方法および光分岐率調整装置
Arkwright et al. High-isolation demultiplexing in bend-tuned twin-core fiber
US20250180828A1 (en) Expanded beam connectors and associated systems and methods
WO2024105776A1 (ja) 光ファイバカプラ、光ファイバカプラの製造方法、及び光合分波方法
WO2025203344A1 (ja) 光コネクタ及び光コネクタプラグの製造方法
WO2025203348A1 (ja) 光コネクタ及び光コネクタプラグの製造方法
Praporshchikov et al. Selection issues of equivalent angular misalignment at regular span splices during piecewise regular fiber optic link simulation
Neumann Components for Single-Mode Fibers
Kihara Optical performance analysis of single-mode fiber connections
Van Hove et al. Termination of small diameter (125/spl mu/m) plastic optical fiber for 1/spl times/12 datacommunication

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23921039

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2024575909

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2024575909

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE