WO2013031836A1 - Système de couplage optique et procédé de couplage - Google Patents

Système de couplage optique et procédé de couplage Download PDF

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Publication number
WO2013031836A1
WO2013031836A1 PCT/JP2012/071848 JP2012071848W WO2013031836A1 WO 2013031836 A1 WO2013031836 A1 WO 2013031836A1 JP 2012071848 W JP2012071848 W JP 2012071848W WO 2013031836 A1 WO2013031836 A1 WO 2013031836A1
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Prior art keywords
optical system
light
coupling
pitch
deflection
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PCT/JP2012/071848
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English (en)
Japanese (ja)
Inventor
橋村　淳司
史生 長井
幸宏 尾関
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コニカミノルタアドバンストレイヤー株式会社
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Publication of WO2013031836A1 publication Critical patent/WO2013031836A1/fr

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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
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/32—Optical coupling means having lens focusing means positioned between opposed fibre ends
    • 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
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4249—Packages, e.g. shape, construction, internal or external details comprising arrays of active devices and fibres
    • 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
    • G02B6/02042—Multicore optical fibres

Definitions

  • the present invention relates to a coupling optical system and a coupling method for coupling optical elements used for optical communication and the like.
  • a multi-core fiber that is an optical fiber in which a plurality of cores are provided in one clad can be used (see Patent Documents 1 and 2). Since the multi-core fiber has a plurality of cores, it is possible to perform large-capacity data communication compared to the single-core fiber.
  • such a multi-core fiber may be used by being optically coupled with, for example, a fiber bundle in which a plurality of single-core fibers are bundled, a light emitting element such as a laser diode, or a light receiving element such as a photodiode. is there.
  • a light emitting element such as a laser diode
  • a light receiving element such as a photodiode.
  • all or part of the multi-core fiber, the fiber bundle, the light emitting element, and the light receiving element may be referred to as “optical element”.
  • the cores When connecting multi-core fibers having the same number of cores, the cores can be reliably connected by aligning the multi-core fibers. Therefore, it is difficult to cause coupling loss, and high coupling efficiency can be achieved.
  • the cores of the multi-core fiber are arranged at a distance narrower than the diameter of each single-core fiber of the fiber bundle. Therefore, when the fiber bundle and the multi-core fiber are coupled, it is difficult to reliably couple the cores. Therefore, the coupling efficiency between the multi-core fiber and the fiber bundle is reduced.
  • the present invention solves the above problems, and provides a coupling optical system capable of suppressing a decrease in coupling efficiency when coupling a multi-core fiber and another optical element, and a coupling method using the same. With the goal.
  • the coupling optical system according to claim 1 includes a plurality of light sources, a plurality of light receiving elements, and any one of a plurality of optical elements bundled with a plurality of single core fibers and a plurality of light elements.
  • the core is disposed between the multi-core fiber covered with the clad and optically couples the optical element and the multi-core fiber.
  • the numerical aperture of each of the plurality of lights incident from the incident side element consisting of one of the optical element and the multi-core fiber is equal to the numerical aperture of each of the plurality of lights exiting toward the exit side element consisting of the other. It is comprised so that it may become.
  • a coupling optical system is the coupling optical system according to the first aspect, and includes a first optical system and a second optical system.
  • the first optical system converges each of the plurality of lights.
  • the second optical system changes the interval between the plurality of lights.
  • the coupling optical system according to claim 3 is the coupling optical system according to claim 2, wherein the first optical system is disposed closer to the optical element than the second optical system. ing.
  • the coupling optical system according to claim 4 can be applied to the coupling optical system according to claim 3.
  • the coupling optical system according to claim 5 is the coupling optical system according to claim 2, wherein the first optical system has a configuration in which a plurality of lenses are arranged in an array. is there.
  • the coupling optical system according to claim 5 can be applied to the coupling optical system according to claim 3 or 4.
  • the coupling optical system according to claim 6 is the coupling optical system according to claim 5, wherein the pitch between the plurality of lenses is the pitch between the plurality of light sources and the plurality of light receptions. It is equal to either the pitch between elements or the pitch between single core fibers.
  • the coupling optical system according to claim 7 is the coupling optical system according to claim 2, and the second optical system is a double-sided telecentric optical system.
  • the coupling optical system according to the seventh aspect can be applied to the coupling optical system according to any one of the third to sixth aspects.
  • the coupling optical system according to claim 8 is the coupling optical system according to claim 2, wherein the magnification of the second optical system is such that the pitch between the plurality of light sources and the plurality of light receptions. It is equal to the ratio of either the pitch between the elements or the pitch between the plurality of single core fibers to the pitch between the cores of the multicore fiber.
  • the coupling optical system according to claim 8 can be applied to the coupling optical system according to any one of claims 3 to 7.
  • a coupling optical system according to a ninth aspect is the coupling optical system according to the first aspect, and includes a deflection optical system. The deflection optical system individually deflects a plurality of incident light.
  • a coupling optical system is the coupling optical system according to the ninth aspect, and includes a collimating lens.
  • the collimating lens collimates light from any of the incident side elements.
  • the deflection optical system deflects light collimated by the collimating lens.
  • the coupling optical system according to claim 11 is the coupling optical system according to claim 10, and the collimating lens has a configuration in which a plurality of collimating lenses are arranged in an array. .
  • the coupling optical system according to claim 12 is the coupling optical system according to claim 11, wherein a pitch between the plurality of collimating lenses is a pitch between the plurality of light sources, a plurality of the plurality of light sources. It is equal to either the pitch between single-core fibers or the pitch between cores of multi-core fibers.
  • the coupling optical system according to claim 13 is the coupling optical system according to claim 10, wherein the deflection optical system includes a first deflection optical system, a second deflection optical system, and including. The first deflection optical system deflects a plurality of incident light.
  • the second deflection optical system further deflects the plurality of lights deflected by the first deflection optical system.
  • the coupling optical system according to the thirteenth aspect can be applied to the coupling optical system according to the eleventh or twelfth aspect.
  • the coupling optical system according to claim 14 is the coupling optical system according to claim 13, wherein one surface of the first deflection optical system and the second deflection optical system is convex. The other side is formed in a concave shape.
  • the coupling optical system according to claim 15 is the coupling optical system according to claim 13, wherein the first deflection optical system and the second deflection optical system are at least one surface of each.
  • the coupling optical system according to claim 16 is the coupling optical system according to claim 13, wherein at least one of the first deflection optical system and the second deflection optical system is a collimating lens. It is a deflecting prism that deflects the light collimated in the above.
  • the coupling optical system according to claim 16 can be applied to the coupling optical system according to claim 14.
  • the coupling optical system according to claim 17 is the coupling optical system according to claim 13, wherein the first deflection optical system and the second deflection optical system have the same degree of deflection.
  • the coupling optical system according to claim 17 can be applied to the coupling optical system according to any one of claims 14 to 16.
  • the coupling optical system according to claim 18 is the coupling optical system according to claim 9, wherein the deflection degree of the deflection optical system is such that the pitch between the plurality of light sources and the plurality of light receptions. It is equal to the ratio of either the pitch between the elements or the pitch between the plurality of single core fibers to the pitch between the cores of the multicore fiber. Note that the coupling optical system according to claim 18 can be applied to the coupling optical system according to any one of claims 10 to 17.
  • a coupling optical system is the coupling optical system according to the tenth aspect, and includes an imaging optical lens.
  • the imaging optical lens forms an image of the light deflected by the deflection optical system on any of the emission side elements.
  • the coupling optical system according to claim 19 can be applied to the coupling optical system according to any of claims 11 to 18.
  • the coupling optical system according to claim 20 is the coupling optical system according to claim 19, and the imaging optical lens has a configuration in which a plurality of lenses are arranged in an array. is there.
  • the coupling optical system according to claim 21 is the coupling optical system according to claim 20, wherein a pitch between the imaging optical lenses is a pitch between a plurality of single core fibers, It is equal to either the pitch between the light receiving elements or the pitch between the cores of the multi-core fiber.
  • a coupling optical system according to a twenty-second aspect is the coupling optical system according to the nineteenth aspect, in which the focal length of the collimating lens is equal to the focal length of the imaging optical lens. Note that the coupling optical system according to claim 22 can be applied to the coupling optical system according to claim 20 or 21.
  • the coupling optical system according to claim 23 is the coupling optical system according to claim 1, wherein the incident side element, the coupling optical system, and the output side element are arranged on the incident side.
  • Each principal ray of light from the element is incident perpendicularly to the incident surface of the coupling optical system, and each principal ray of light emitted from the exit surface of the coupling optical system is perpendicular to the light receiving surface of the emitting element. The arrangement is incident.
  • the coupling optical system according to claim 23 can be applied to the coupling optical system according to any one of claims 2 to 22.
  • the coupling method according to claim 24 uses the coupling optical system according to any one of claims 1 to 23, and uses a coupling optical system according to any one of claims 1 to 23 to obtain a numerical aperture for each of a plurality of lights incident from an incident side element. And the optical element and the multi-core fiber are coupled so that the numerical apertures of the plurality of lights emitted toward the emission side element are equal.
  • the numerical apertures of the plurality of lights incident from the incident side element are equal to the numerical apertures of the plurality of lights emitted toward the emission side element. Designed to be Accordingly, it is possible to suppress a decrease in coupling efficiency when coupling the multi-core fiber and another optical element.
  • FIG. 10 is a view showing a coupling member according to Modifications 2 to 4 common to the first to third embodiments.
  • FIG. 10 is a diagram showing multicore fibers according to Modifications 2 to 4 common to the first to third embodiments.
  • FIG. 6 is a view showing a multi-core fiber and a coupling member according to Modifications 2 to 4 common to the first to third embodiments.
  • FIG. 1 is a perspective view of the multi-core fiber 1. In FIG. 1, only the tip portion of the multi-core fiber 1 is shown.
  • the multi-core fiber 1 is made of a material having a high light transmittance such as quartz glass or plastic.
  • the core C k is a transmission path for transmitting light from a light source (not shown).
  • the core C k is made of a material in which germanium oxide (GeO 2 ) is added to, for example, quartz glass.
  • FIG. 1 shows a configuration having seven cores C 1 to C 7 , the number of cores C k may be at least two.
  • the clad 2 is a member that covers the plurality of cores Ck .
  • Cladding 2 has a function to confine light from a light source (not shown) in the core C k.
  • the clad 2 has an end face 2a.
  • the end surface Ek of the core Ck and the end surface 2a of the clad 2 form the same surface (the end surface 1b of the multicore fiber 1).
  • the cladding 2 material a low refractive index material is used than the core C k material.
  • quartz glass is used as the material of the clad 2.
  • the refractive index of the core C k higher than the refractive index of the cladding 2
  • the light from the light source (not shown) is totally reflected at the interface between the core C k and the cladding 2. Therefore, light can be transmitted in the core Ck .
  • FIG. 2 is a sectional view in the axial direction of the coupling optical system 20, the fiber bundle 10, and the multicore fiber 1.
  • the fiber bundle 10 includes a plurality of single core fibers 100.
  • the single core fiber 100 includes a core C inside a clad 101.
  • the core C is a transmission path for transmitting light from a light source (not shown).
  • the light emitted from the end surface Ca of the core C is incident on the incident surface (described later) of the coupling optical system 20 with a predetermined numerical aperture NA.
  • N is a refractive index.
  • ⁇ is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light beam) emitted from the end face Ca enters the coupling optical system 20.
  • the coupling optical system 20 includes a first optical system 21 and a second optical system 22.
  • the first optical system 21 has a function of converging each of the plurality of lights.
  • the second optical system 22 has a function of changing the interval between the plurality of lights.
  • the first optical system 21 in the present embodiment has a function of converging each of a plurality of lights from the fiber bundle 10.
  • the first optical system 21 includes a plurality of convex lenses 21a arranged in an array.
  • the plurality of convex lenses 21 a are provided in the same number as the single core fibers 100 included in the fiber bundle 10.
  • the first optical system 21 (convex lens 21a) is disposed at a position where each light (principal ray Pr) emitted from each end face Ca of the fiber bundle 10 enters perpendicularly to the surface of the corresponding convex lens 21a. (In this case, the end face Ca functions as a stop).
  • the plurality of convex lenses 21a has a pitch P m (a distance between optical axes of adjacent convex lenses 21a).
  • a pitch P out between a plurality of single core fibers 100 (a distance between optical axes of adjacent single core fibers 100.
  • a fiber bundle The distance between the optical axis of the core C of the fiber disposed at the center of the fiber 10 and the optical axis of the core C of the fiber disposed at the periphery thereof is disposed.
  • the first optical system 21 is disposed closer to the fiber bundle 10 than the second optical system 22.
  • the surface of the convex lens 21a on which the light from the fiber bundle 10 is incident is an example of an “incident surface”.
  • the plurality of convex lenses 21a in the present embodiment is an example of “a plurality of lenses”.
  • the magnification of the first optical system 21 is designed to be a predetermined magnification ⁇ m.
  • ⁇ ′ is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light beam) emitted from the first optical system 21 reaches the imaging point IP.
  • the second optical system 22 in the present embodiment has a function of narrowing the interval between the plurality of lights from the first optical system 21.
  • the second optical system 22 is constituted by a double-sided telecentric optical system including two convex lenses 22a and 22b.
  • the second optical system 22 is arranged at a position where each of the plurality of lights (principal rays Pr) from the first optical system 21 is perpendicularly incident on the end face E k of each core C k of the corresponding multi-core fiber 1. ing.
  • the light (light beam) emitted from the second optical system 22 is an angle principal ray Pr and marginal rays Mr forms as they enter the multi-core fiber 1 (end surface E k of each core C k).
  • the surface of the convex lens 22b from which the light from the first optical system 21 is emitted is an example of an “emission surface”.
  • the end surface E k is an example of a “light receiving surface”.
  • the second optical system 22 has a magnification ⁇ r of the pitch P out between the single core fibers 100 and the pitch P in between the cores C k of the multi-core fiber 1 (adjacent cores in the multi-core fiber 1).
  • C k of the distance between the optical axes are designed to be equal to the ratio of the distance) between the optical axes of the periphery of the core C 2 of the center of the core C 1 of the multi-core fiber 1.
  • the ratio of the magnification ⁇ r and the pitch P out to the pitch P in does not necessarily have to be equal depending on the tolerance of the optical element used and variations in design. Any value that can secure at least the coupling efficiency necessary for optical transmission, for example, a value satisfying the following expression (1) may be used.
  • the coupling optical system 20 is designed so that the numerical aperture NA is equal to the numerical aperture NA ′′.
  • magnification ⁇ m of the first optical system 21 and the magnification ⁇ r of the second optical system 22 are designed so as to satisfy the following expression (2).
  • magnification ⁇ m and the magnification ⁇ r does not necessarily satisfy the condition of the expression (2) due to the tolerance of the optical element used and variations in design. Any value that can secure at least the coupling efficiency necessary for optical transmission, for example, a value satisfying the following expression (3) may be used.
  • the configuration of the coupling optical system 20 arranged so that the light emitted from the first optical system 21 enters the second optical system 22 has been described.
  • the first optical system 21 and the second optical system 21 The arrangement of the system 22 may be reversed.
  • the magnification ⁇ m of the first optical system 21 and the magnification ⁇ r of the second optical system 22 need only satisfy the relationship of Expression (2) or Expression (3).
  • the fiber bundle 10 in the present embodiment is an example of an “incident side element”.
  • the multi-core fiber 1 in the present embodiment is an example of an “emission side element”.
  • each light (principal ray Pr) emitted from the end face Ca is incident on the first optical system 21 (the surface of the convex lens 21a) perpendicularly.
  • Each of the plurality of lights (principal rays Pr) incident on the first optical system 21 is perpendicularly incident on the second optical system 22 (surface of the convex lens 22a) with the imaging point IP as a secondary light source.
  • the numerical aperture (equal to NA ′) when each of the plurality of lights enters the second optical system 22 is smaller than the numerical aperture NA. Therefore, the configuration of the second optical system 22 can be simplified.
  • the second optical system 22 is formed of a bilateral telecentric optical system. Accordingly, the plurality of light beams (principal rays Pr) incident perpendicularly to the second optical system 22 are emitted vertically from the second optical system 22 (surface of the convex lens 22b) in a state where the distance between them is narrowed.
  • a fiber bundle 10 of pitch P out is 120 ⁇ m between the plurality of single-core fiber 100 will be described a case where the pitch P in between the core C k are attached to the multi-core fiber 1 of 40 [mu] m.
  • the corresponding light (principal ray Pr) can be vertically incident on the plurality of cores C k of the multi-core fiber 1.
  • the pitch P in and the pitch P out can be arbitrarily set when the multi-core fiber 1 and the fiber bundle 10 are optically designed.
  • the pitch P out can be set between about 100 to 150 ⁇ m.
  • the pitch P in for example, can be arbitrarily set between about 30 ⁇ 50 [mu] m.
  • the target for emitting the light is not limited thereto.
  • a plurality of light sources can be used instead of the fiber bundle 10.
  • the light source is an example of an “incident side element”.
  • the above-mentioned “P out ” is the pitch between adjacent light sources (for example, the distance between the center of the exit surface of the light source disposed at the center and the center of the exit surface of the light source disposed around the center).
  • the multi-core fiber 1 is an example of an “incident side element”.
  • the fiber bundle 10 or the light receiving element is an example of the “outgoing side element”.
  • the second optical system 22 in this modification has a function of widening the interval between a plurality of lights emitted from the multicore fiber 1.
  • the surface of the convex lens 22b on which the light from the multicore fiber 1 is incident is an example of an “incident surface”.
  • the first optical system 21 in this modification has a function of converging each of the plurality of lights from the second optical system 22. Each converged light (principal ray Pr) is perpendicularly incident on the end face Ca of the corresponding core C.
  • the surface of the first optical system 21 (convex lens 21a) from which the light from the second optical system 22 is emitted is an example of an “emission surface”.
  • the end surface Ca is an example of a “light receiving surface”.
  • [Theta] in this modification is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light flux) emitted from the first optical system 21 enters the fiber bundle 10 (each single core fiber 100).
  • ⁇ ′ is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light beam) emitted from the second optical system 22 reaches the imaging point IP.
  • ⁇ ′′ is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light beam) emitted from the multicore fiber 1 enters the second optical system 22.
  • the above “P out ” is arranged at the pitch between adjacent light receiving elements (for example, the center of the light receiving surface of the light receiving element arranged at the center and the periphery thereof). Distance from the center of the light receiving surface of the light receiving element.
  • the coupling optical system 20 includes an optical element including any one of a plurality of light sources, a plurality of light receiving elements, and a fiber bundle 10 in which a plurality of single core fibers 100 are bundled, and a plurality of cores C k are clad 2.
  • the optical element and the multi-core fiber 1 are optically coupled to each other.
  • the coupling optical system 20 includes a numerical aperture of each of a plurality of lights incident from an incident side element composed of one of the optical element and the multi-core fiber 1, and a numerical aperture of each of the plurality of lights emitted toward an output side element composed of the other. Are designed to be equal.
  • the coupling optical system 20 includes a first optical system 21 and a second optical system 22.
  • the first optical system 21 converges each of the plurality of lights.
  • the second optical system 22 changes (narrows / expands) the interval between the plurality of lights.
  • the coupling efficiency is obtained by combining the first optical system 21 and the second optical system 22 so that the numerical aperture of the light incident on the coupling optical system 20 and the numerical aperture of the light emitted from the coupling optical system 20 do not change.
  • Light can be transmitted without dropping light. That is, according to the coupling optical system 20 in the present embodiment, the optical element and the multicore fiber 1 can be optically coupled while suppressing a decrease in coupling efficiency.
  • the first optical system 21 is arranged closer to the optical element than the second optical system 22.
  • the numerical aperture NA ′ of light incident on the second optical system 22 from the first optical system 21 (or the aperture of light incident on the first optical system 21 from the second optical system 22).
  • the number NA ′) can be kept small, so that the configuration of the optical system can be simplified.
  • the first optical system 21 has a configuration in which a plurality of lenses 21a are arranged in an array.
  • the first optical system 21 can be designed with a simple configuration using a single lens of the same shape.
  • the pitch Pm between the plurality of lenses 21a are between the plurality of light sources pitch, the pitch P out between pitch and a plurality of single-core fiber 100 between the plurality of light receiving elements Designed to be equal to either.
  • each of the light (principal ray Pr) from the plurality of single core fibers 100 can be perpendicularly incident on the surface of the corresponding plurality of lenses 21a (that is, the light beam from the single core fiber 100 is axially coupled). Can be treated as the upper luminous flux).
  • each of the plurality of lights (principal rays Pr) emitted from the plurality of lenses 21a can be perpendicularly incident on the end surfaces Ca of the plurality of single core fibers 100 and the surfaces of the plurality of light receiving elements. Accordingly, it is possible to suppress a decrease in coupling efficiency.
  • the second optical system 22 is a double-sided telecentric optical system.
  • magnification ⁇ r of the second optical system 22 is any of the pitch between the plurality of light sources, the pitch between the plurality of light receiving elements, and the pitch P out between the plurality of single core fibers 100, and the multicore fiber 1. It is designed to be equal to the ratio of the pitch P in between the cores C k of the two.
  • each of the plurality of lights (principal rays Pr) from the coupling optical system 20 may be perpendicularly incident on the core C k (or the corresponding plurality of light receiving elements, the fiber bundle 10) of the corresponding multicore fiber 1. It becomes possible. Accordingly, it is possible to suppress a decrease in coupling efficiency.
  • FIG. 3 is a sectional view in the axial direction of the coupling optical system 30, the fiber bundle 10, and the multicore fiber 1. A detailed description of the configuration similar to that of the first embodiment, such as the configuration of the fiber bundle 10, may be omitted.
  • the coupling optical system 30 includes a collimating optical system 31, a deflection optical system 32, and an imaging optical system 33.
  • the collimating optical system 31 has a function of collimating each of a plurality of lights from the fiber bundle 10.
  • the collimating optical system 31 includes a plurality of collimating lenses 31a arranged in an array.
  • the plurality of collimating lenses 31 a are provided in the same number as the single core fibers 100 included in the fiber bundle 10.
  • the collimating optical system 31 (collimating lens 31a) is disposed at a position where light (principal ray Pr) emitted from each end face Ca enters perpendicularly to the surface of the corresponding collimating lens 31a. In this case, the end face Ca functions as a diaphragm).
  • the plurality of collimating lenses 31a has a pitch P cl (the distance between the optical axes of adjacent collimating lenses 31a.
  • P cl the distance between the optical axes of adjacent collimating lenses 31a.
  • the lens center of the collimating lens 31a disposed at the center and the lens center of the collimating lens 31a disposed at the periphery thereof. Is arranged to be equal to the pitch P out between the plurality of single core fibers 100 (the distance between the optical axes of adjacent single core fibers 100).
  • the collimating optical system 31 is arranged on the fiber bundle 10 side with respect to the deflection optical system 32.
  • the surface of the collimating lens 31a on which the light from the fiber bundle 10 is incident is an example of an “incident surface”.
  • the deflection optical system 32 has a function of individually deflecting a plurality of incident light (in this embodiment, light from the fiber bundle 10).
  • the deflection optical system 32 in this embodiment includes a first deflection prism 32a and a second deflection prism 32b.
  • the first deflection prism 32a in the present embodiment is an example of a “first deflection optical system”.
  • the second deflection prism 32b in the present embodiment is an example of a “second deflection optical system”.
  • the first deflection prism 32a in this embodiment has a function of deflecting each of a plurality of lights collimated by the collimating optical system 31 (collimating lens 31a) in a predetermined direction while being collimated. As shown in FIG. 3, the first deflection prism 32a is designed so that light passing through the center thereof is not deflected. The first deflection prism 32a has an incident surface 321a and an exit surface 322a corresponding to the number of incident light. The first deflecting prism 32a in the present embodiment is designed such that each of the plurality of lights (principal rays Pr) from the collimating optical system 31 is incident on the corresponding incident surface 321a perpendicularly.
  • the incident surface 321a is a flat surface.
  • the emission surface 322a is formed as a convex surface corresponding to the number of light beams.
  • the emission surface 322a is designed to be inclined by a predetermined angle ⁇ .
  • FIG. 4A is an enlarged view of a part of the cross section of the first deflection prism 32a.
  • the incident angle of light incident on the exit surface 322a of the first deflecting prism 32a (only the principal ray Pr is shown in the figure) is ⁇ in , and the light deflected by the first deflecting prism 32a and emitted (the principal ray Pr is shown in the figure).
  • emission angle gamma out only shown) a pitch between the plurality of single-core fiber 100 P out, the pitch between the cores C k of the multicore fiber 1 P in, the first deflecting prism 32a and the second deflecting prism 32b Let the interval be t.
  • the incident angle ⁇ in is equal to the tilt angle ⁇ .
  • the emission angle ⁇ out is determined by the following equation (4).
  • the incident angle ⁇ in satisfies the relationship of the following equation (5).
  • the emission angle ⁇ out is about 14.9 °.
  • the first deflecting prism 32a is formed of a material having a base material refractive index of 1.6 with respect to the emission angle ⁇ out , the incident angle ⁇ in is about 9.25 °. Therefore, the emission surface 322a of the first deflecting prism 32a can be designed so that the inclination angle ⁇ is about 9.25 °.
  • the incident surface 321a may be a convex surface.
  • the inclination angle ⁇ ′ is determined as follows, for example.
  • FIG. 4B is an enlarged view of a part of the cross section of the first deflecting prism 32a.
  • the incident angle of light incident on the incident surface 321a of the first deflecting prism 32a is ⁇ ′ in
  • the deflection angle of the incident light is ⁇ ′ 1
  • the perpendicular to the incident surface 321a The angle of the incident light is ⁇ ′ 2
  • the emission angle of the light that is deflected and emitted by the first deflecting prism 32 a is ⁇ ′ out
  • the pitch between the single core fibers 100 is P out
  • the pitch between the cores C k of the multi-core fiber 1 is P in
  • the interval between the first deflection prism 32a and the second deflection prism 32b is t.
  • the incident angle ⁇ ′ in is equal to the inclination angle ⁇ ′.
  • the emission angle ⁇ out is determined by the above equation (4).
  • the incident angle ⁇ ′ in , the deflection angle ⁇ ′ 1 , and the angle ⁇ ′ 2 have the relationship of the following formula (6).
  • the incident angle ⁇ ′ in and the angle ⁇ ′ 2 have the relationship of the following expression (8) according to Snell's law.
  • N′sin [ ⁇ ′ in ] N′sin [ ⁇ ′ 2 ] (8)
  • the emission angle ⁇ out is about 14.9 °.
  • the incident angle ⁇ in is about 24 °. Therefore, the incident surface 321a of the first deflection prism 32a can be designed so that the inclination angle ⁇ ′ is about 24 °.
  • the second deflection prism 32b in the present embodiment has a function of further deflecting each light deflected by the first deflection prism 32a.
  • each of the plurality of lights (principal rays Pr) from the second deflecting prism 32 b is deflected in a direction perpendicularly incident on the imaging optical system 33. Even when the light is deflected by the second deflecting prism 32b, the state in which each of the plurality of lights is collimated does not change.
  • the second deflection prism 32b is designed so that light passing through the center thereof is not deflected.
  • the second deflection prism 32b has an incident surface 321b and an exit surface 322b corresponding to the number of incident light.
  • the incident surface 321b is formed as a concave surface corresponding to the number of light beams.
  • the emission surface 322b is formed in a plane. Further, the emission surface 322b can be a concave surface.
  • the inclination angle of the concave surface of the second deflection prism 32b can be obtained by a method similar to the method for obtaining the inclination angle of the first deflection prism 32a described above.
  • the first deflecting prism 32a and the second deflecting prism 32b are separately configured.
  • the deflecting optical system 32 may be composed of one deflecting prism 32 ′.
  • An example is shown in FIG. FIG. 5 is a side view of the deflection prism 32 ′.
  • the deflecting prism 32 ′ is formed with an incident surface 32 ′ a on which light from the collimating optical system 31 is incident and an output surface 32 ′ b that emits light to the imaging optical system 33.
  • the incident surface 32′a is formed, for example, in the same manner as the emission surface 322a of the first deflection prism 32a described above.
  • the exit surface 32'b is formed, for example, in the same manner as the entrance surface 321b of the second deflection prism 32b described above.
  • the deflection optical system 32 has a predetermined degree of deflection R.
  • the degree of deflection R is the amount of change in the angle of the principal ray Pr incident on the deflection optical system 32 and the angle of the principal ray Pr emitted from the deflection optical system 32.
  • the degree of deflection can also be expressed by the ratio of the light flux height of light incident on the deflection optical system 32 (the distance from the central light flux to another light flux) and the light flux height of light emitted from the deflection optical system 32.
  • the degree of deflection R depends on the angle of the principal ray Pr incident on the first deflection prism 32a and the principal ray Pr emitted from the second deflection prism 32b. The amount of change in the angle. In this case, it can be said that the degree of deflection R is a combination of the degree of deflection R1 of the first deflection prism 32a and the degree of deflection R2 of the second deflection prism 32b.
  • the degree of deflection R1 of the first deflection prism 32a is designed to be equal to the degree of deflection R2 of the second deflection prism 32b.
  • the degree of deflection R (R1 + R2) is designed to be equal to the ratio of the pitch P out between the plurality of single core fibers 100 and the pitch P in between the cores C k of the multi-core fiber 1. Yes.
  • the imaging optical system 33 has a function of imaging each of a plurality of lights (light beams) deflected by the deflection optical system 32 on each core C k of the multi-core fiber 1.
  • the imaging optical system 33 includes a plurality of imaging optical lenses 33a arranged in an array.
  • the plurality of imaging optical lenses 33a are provided in the same number as each core C k of the multi-core fiber 1.
  • An imaging optical system 33 (the imaging optical lens 33a), the light emitted from the deflecting optical system 32 (main beam Pr) is disposed in a position that is incident perpendicularly to the end face E k of each core C k corresponding Has been.
  • the plurality of image forming optical lenses 33a are arranged at the pitch P im (the distance between the optical axes of adjacent image forming optical lenses 33a.
  • the center of the image forming optical lens 33a disposed at the center and the periphery thereof. distance between the lens center of the image-forming optical lens 33a) is arranged to be equal to the pitch P in between the core C k.
  • NA'', the light (light beam) emitted from the imaging optical system 33 is an angle principal ray Pr and marginal rays Mr forms as they enter the multi-core fiber 1 (end surface E k of each core C k).
  • the surface of the imaging optical lens 33a from which the light from the deflection optical system 32 is emitted is an example of an “emission surface”.
  • the end surface E k is an example of a “light receiving surface”.
  • the coupling optical system 30 is designed so that the numerical aperture NA and the numerical aperture NA ′′ are equal.
  • the focal length f cl of the collimating optical system 31 (collimating lens 31a) and the imaging optical system 33 (imaging optical lens 33a) are set.
  • the coupling optical system 30 is designed so that the focal length f im becomes equal.
  • the relationship between the focal length f cl and the focal length f im is not necessarily equal due to tolerances of optical elements used and variations in design. Any value that can secure at least the coupling efficiency necessary for optical transmission, for example, a value that satisfies the following equation (9) may be used.
  • the fiber bundle 10 in the present embodiment is an example of an “incident side element”.
  • the multi-core fiber 1 in the present embodiment is an example of an “emission side element”.
  • each end face Ca is emitted from the end face Ca of the core C provided in each of the plurality of single core fibers 100.
  • Light emitted from each end face Ca enters the collimating optical system 31 (collimating lens 31a) with a predetermined numerical aperture NA while being diffused.
  • each light (principal ray Pr) emitted from the end face Ca is incident perpendicularly to the collimating optical system 31 (the surface of the collimating lens 31a).
  • Each of the plurality of lights incident on the collimating optical system 31 is collimated and enters the first deflecting prism 32a.
  • the first deflection prism 32a individually deflects each of the plurality of lights with a predetermined degree of deflection R1.
  • Each deflected light is incident on the second deflecting prism 32b.
  • the second deflection prism 32b individually deflects a plurality of lights with a predetermined degree of deflection R2. Each light deflected by the second deflection prism 32 b enters the imaging optical system 33. Each light incident on the imaging optical system 33 is incident on the core C k of the corresponding multi-core fiber 1.
  • a fiber bundle 10 of pitch P out is 120 ⁇ m between the plurality of single-core fiber 100 will be described a case where the pitch P in between the core C k are attached to the multi-core fiber 1 of 40 [mu] m.
  • the pitch P cl is 120 ⁇ m and the pitch P im is 40 ⁇ m.
  • the pitch P in and the pitch P out can be arbitrarily set when the multi-core fiber 1 or the fiber bundle 10 is optically designed.
  • the pitch P out can be set between about 100 to 150 ⁇ m.
  • the pitch P in for example, can be arbitrarily set between about 30 ⁇ 50 [mu] m.
  • the target for emitting the light is not limited thereto.
  • a plurality of light sources can be used instead of the fiber bundle 10.
  • the light source is an example of an “incident side element”.
  • the above-mentioned “P out ” is a pitch between adjacent light sources.
  • the multi-core fiber 1 is an example of an “incident side element”.
  • the fiber bundle 10 or the light receiving element is an example of the “outgoing side element”.
  • the imaging optical system 33 in this modification has a function of collimating each of a plurality of lights emitted from the multicore fiber 1. That is, in the present modification, the imaging optical system 33 corresponds to the “collimating optical system”. In the present modification, the surface of the imaging optical lens 33a on which the light from the multicore fiber 1 is incident is an example of an “incident surface”. In addition, the pitch between the imaging optical lenses 33 a in this modification is equal to the pitch between the cores C k of the multicore fiber 1.
  • the deflection optical system 32 in this modification has a function of deflecting each of a plurality of lights from the imaging optical system 33.
  • Each deflected light (principal ray Pr) enters the collimating optical system 31 perpendicularly.
  • the collimating optical system 31 in this modification has a function of imaging each of a plurality of lights emitted from the deflection optical system 32 on the core C of the corresponding single core fiber 100. That is, in this modification, the collimating optical system 31 corresponds to the “imaging optical system”.
  • the surface of the collimating optical system 31 (collimating lens 31a) from which the light from the deflection optical system 32 is emitted is an example of an “exiting surface”.
  • the end surface Ca is an example of a “light receiving surface”.
  • the pitch between the collimating lenses 31 a is equal to the pitch between the cores C of the single core fiber 100.
  • the first deflection prism 32a is the “second deflection optical system”.
  • the second deflection prism 32b is an example of the “first deflection optical system”.
  • ⁇ in this modification is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light flux) emitted from the collimating optical system 31 enters the fiber bundle 10 (each single core fiber 100).
  • ⁇ ′′ is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light beam) emitted from the multicore fiber 1 enters the imaging optical system 33.
  • the degree of deflection R in the present modification is equal to the ratio between the pitch between the plurality of light receiving elements and the pitch between the cores C k of the multicore fiber 1.
  • the pitch between the collimating lenses 31a is equal to the pitch between the light receiving elements.
  • the coupling optical system 30 includes a deflection optical system 32 that individually deflects a plurality of incident light.
  • the deflection optical system 32 is used as the coupling optical system 30, light can be transmitted without reducing the coupling efficiency. That is, according to the coupling optical system 30 in the present embodiment, the optical element and the multicore fiber 1 can be optically coupled while suppressing a decrease in coupling efficiency.
  • the coupling optical system 30 includes a collimating optical system 31.
  • the collimating optical system 31 collimates light from any of the incident side elements.
  • the deflecting optical system 32 deflects the light collimated by the collimating optical system 31.
  • the collimating optical system 31 has a configuration in which a plurality of collimating lenses 31a are arranged in an array.
  • the collimating optical system 31 can be designed with a simple configuration using a single lens of the same shape.
  • the pitch P cl between the plurality of collimating lenses 31a is equal to any of the pitch between the plurality of light sources, the pitch P out between the plurality of single core fibers, and the pitch P in between the cores of the multicore fibers. Designed to be
  • each of the light (principal ray Pr) from the plurality of single core fibers 100 can be perpendicularly incident on the surface of the collimating lens 31a (that is, the light flux from the single core fiber 100 is treated as an axial light flux. be able to).
  • each of the plurality of lights (principal rays Pr) emitted from the collimator lens 31a can be perpendicularly incident on the end surfaces Ca of the plurality of single core fibers 100 and the surfaces of the plurality of light receiving elements. Accordingly, it is possible to suppress a decrease in coupling efficiency.
  • the deflection optical system 32 includes a first deflection optical system (first deflection prism 32a) and a second deflection optical system (second deflection prism 32b).
  • the first deflection optical system deflects a plurality of incident light.
  • the second deflection optical system further deflects the plurality of lights deflected by the first deflection optical system.
  • the optical element and the multicore fiber 1 can be optically coupled while suppressing a decrease in coupling efficiency.
  • one side is formed in a convex shape and the other side is formed in a concave shape.
  • the deflection optical system 32 according to the present embodiment is designed so that the degree of deflection R1 of the first deflection optical system is equal to the degree of deflection R2 of the second deflection optical system.
  • the deflection degree R of the deflection optical system 32 is any of the pitch between the plurality of light sources, the pitch between the plurality of light receiving elements, and the pitch P out between the plurality of single core fibers, and the multicore fiber 1. It is designed to be equal to the ratio between the pitch P in between the core C k.
  • each of the light (principal ray Pr) incident from the incident side element can be made to enter perpendicularly to the surface of the emission side element. That is, it is possible to suppress a decrease in coupling efficiency.
  • the coupling optical system 30 includes an imaging optical system 33 (imaging optical lens 33a).
  • the imaging optical system 33 forms an image of the light deflected by the deflection optical system 32 on one of the emission side elements.
  • the imaging optical lens 33a has a configuration in which a plurality of lenses are arranged in an array.
  • the pitch P im between the imaging optical lenses 33a is the pitch P out between the plurality of single core fibers 100, the pitch between the light receiving elements, and the pitch P in between the cores C k of the multi-core fiber 1. Designed to be equal to either.
  • each of the lights (principal rays Pr) emitted from the imaging optical system 33 can be made to enter perpendicularly to the surface of the emission side element. That is, it is possible to suppress a decrease in coupling efficiency.
  • the focal length f cl of the collimating lens 31a is designed to be equal to the focal length f im of the imaging optical lens 33a.
  • the numerical aperture of the light incident on the coupling optical system 30 and the numerical aperture of the light emitted from the coupling optical system 30 can be kept unchanged, so that light can be transmitted without reducing the coupling efficiency. I can do it. That is, according to the coupling optical system 30 in the present embodiment, the optical element and the multicore fiber 1 can be optically coupled while suppressing a decrease in coupling efficiency.
  • FIG. 6 is a cross-sectional view in the axial direction of the coupling optical system 30 ′, the fiber bundle 10, and the multicore fiber 1. Note that detailed description of the configuration of the fiber bundle 10 and the like similar to those of the first and second embodiments may be omitted.
  • the coupling optical system 30 ′ includes a collimating optical system 31, a deflection optical system 34, and an imaging optical system 33.
  • the collimating optical system 31 and the imaging optical system 33 have the same configuration as in the second embodiment.
  • the deflection optical system 34 in the present embodiment includes a first diffractive optical system 34a and a second diffractive optical system 34b.
  • the first diffractive optical system 34a in the present embodiment is an example of a “first deflection optical system”.
  • the second diffractive optical system 34b in the present embodiment is an example of a “second deflecting optical system”.
  • the first diffractive optical system 34a in this embodiment has a function of deflecting each of a plurality of lights collimated by the collimating optical system 31 (collimating lens 31a) in a predetermined direction by diffraction while being collimated. As shown in FIG. 6, the first diffractive optical system 34a is designed so that light passing through the center thereof is not deflected.
  • the first diffractive optical system 34a has an incident surface 341a and exit surfaces 342a and 343a corresponding to the number of incident light.
  • the first diffractive optical system 34a in the present embodiment is designed such that each of a plurality of lights (principal rays Pr) from the collimating optical system 31 is incident perpendicularly to the corresponding incident surface 341a.
  • the incident surface 341a is formed in a flat surface. Light from the collimating optical system 31 is incident on the incident surface 341a.
  • the exit surface 342a is formed as a diffraction grating composed of a sawtooth projection. On the other hand, no diffraction grating is formed on the exit surface 343a. Therefore, the light passing through the emission surface 343a is not deflected by diffraction.
  • FIG. 7 is a view of the emission surface 342a and the emission surface 343a as seen from the direction of arrow A in FIG.
  • the emission surface 342a and the emission surface 343a in this embodiment have seven surfaces F k (F 1 to F 7 ) for emitting light from the seven single core fibers 100, respectively.
  • the surface F 1 (the emission surface 343a) transmits the light from the single core fiber 100 without being deflected.
  • Diffraction gratings are formed on the surfaces F 2 to F 7 (outgoing surface 342a) with a pitch d (interval between projections). In this embodiment, the pitches d of the diffraction gratings are all equal.
  • This pitch d is determined as follows, for example.
  • the incident angle of light incident on the exit surface 342a is ⁇ in
  • the exit angle of light deflected by the exit surface 342a is ⁇ out
  • the base material refractive index of the first diffractive optical system 34a is N
  • the exit side The refractive index of the medium is N ′
  • the diffraction order is m
  • the wavelength of incident light is ⁇ .
  • the pitch d is determined by the following equation (10).
  • the light enters perpendicularly to the emission surface 342 a.
  • the second diffractive optical system 34b in the present embodiment has a function of further deflecting each light deflected by the first diffractive optical system 34a.
  • each of the plurality of lights (principal rays Pr) from the second diffractive optical system 34 b is deflected in a direction perpendicularly incident on the imaging optical system 33. Even when the light is deflected by the second diffractive optical system 34b, the state in which each of the plurality of lights is collimated does not change.
  • the second diffractive optical system 34b is designed so that light passing through the center thereof is not deflected.
  • the second diffractive optical system 34b has incident surfaces 341b and 342b and an emission surface 343b corresponding to the number of incident light.
  • the incident surface 341b is formed as a diffraction grating composed of a sawtooth projection. On the other hand, no diffraction grating is formed on the incident surface 342b. Therefore, the light passing through the incident surface 342b is not deflected by diffraction. Light from the first diffractive optical system 34a is incident on the incident surfaces 341b and 342b.
  • the emission surface 343b is formed in a plane.
  • Each of the plurality of lights (principal rays Pr) emitted from the emission surface 343b is perpendicularly incident on the imaging optical system 33 (imaging optical lens 33a).
  • the pitch in the second diffractive optical system 34b can be obtained by a method similar to the method for obtaining the pitch d in the first diffractive optical system 34a.
  • the fiber bundle 10 in the present embodiment is an example of an “incident side element”.
  • the multi-core fiber 1 in the present embodiment is an example of an “emission side element”.
  • each end face Ca is emitted from the end face Ca of the core C provided in each of the plurality of single core fibers 100.
  • Light emitted from each end face Ca enters the collimating optical system 31 (collimating lens 31a) with a predetermined numerical aperture NA while being diffused.
  • each light (principal ray Pr) emitted from the end face Ca is incident perpendicularly to the collimating optical system 31 (the surface of the collimating lens 31a).
  • Each of the plurality of lights incident on the collimating optical system 31 is collimated and enters the first diffractive optical system 34a.
  • the first diffractive optical system 34a individually deflects a plurality of incident light beams by a diffraction grating. Each deflected light enters the second diffractive optical system 34b.
  • the second diffractive optical system 34b deflects a plurality of incident light individually. Each light deflected by the second diffractive optical system 34 b enters the imaging optical system 33. Each light incident on the imaging optical system 33 is incident on the core C k of the corresponding multi-core fiber 1.
  • the target for emitting the light is not limited thereto.
  • a plurality of light sources can be used instead of the fiber bundle 10.
  • the light source is an example of an “incident side element”.
  • the above-mentioned “P out ” is a pitch between adjacent light sources.
  • the multi-core fiber 1 is an example of an “incident side element”.
  • the fiber bundle 10 or the light receiving element is an example of the “outgoing side element”.
  • the imaging optical system 33 in this modification has a function of collimating each of a plurality of lights emitted from the multicore fiber 1. That is, in the present modification, the imaging optical system 33 corresponds to the “collimating optical system”. In the present modification, the surface of the imaging optical lens 33a on which the light from the multicore fiber 1 is incident is an example of an “incident surface”. In addition, the pitch between the imaging optical lenses 33 a in this modification is equal to the pitch between the cores C k of the multicore fiber 1.
  • the deflection optical system 34 in this modification has a function of deflecting each of a plurality of lights from the imaging optical system 33 by a diffraction grating.
  • Each deflected light (principal ray Pr) enters the collimating optical system 31 perpendicularly.
  • the collimating optical system 31 in the present modification has a function of imaging each of a plurality of lights emitted from the deflection optical system 34 on the core C of the corresponding single core fiber 100. That is, in this modification, the collimating optical system 31 corresponds to the “imaging optical system”.
  • the surface of the collimating optical system 31 (collimating lens 31a) from which the light from the deflection optical system 34 is emitted is an example of an “exiting surface”.
  • the end surface Ca is an example of a “light receiving surface”.
  • the pitch between the collimating lenses 31 a is equal to the pitch between the cores C of the single core fiber 100.
  • first diffractive optical system 34a and second diffractive optical system 34b are used as the deflecting optical system 34 as in the embodiment
  • the first diffractive optical system 34a is “second deflecting optical system 34a”.
  • the second diffractive optical system 34b is an example of a “first deflecting optical system”.
  • ⁇ in this modification is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light flux) emitted from the collimating optical system 31 enters the fiber bundle 10 (each single core fiber 100).
  • ⁇ ′′ is an angle formed by the principal ray Pr and the marginal ray Mr when the light (light beam) emitted from the multicore fiber 1 enters the imaging optical system 33.
  • the degree of deflection R in the present modification is equal to the ratio between the pitch between the plurality of light receiving elements and the pitch between the cores C k of the multicore fiber 1.
  • the pitch between the collimating lenses 31a is equal to the pitch between the light receiving elements.
  • the first deflecting optical system (first diffractive optical system 34a) and the second deflecting optical system (second diffractive optical system 34b) according to this embodiment are formed as diffraction gratings on at least a part of each one surface.
  • the diffractive optical system (the first diffractive optical system 34a and the second diffractive optical system 34b) is used as the deflection optical system, light can be transmitted without reducing the coupling efficiency. That is, according to the coupling optical system 30 ′ in this embodiment, the optical element and the multicore fiber 1 can be optically coupled while suppressing a decrease in coupling efficiency.
  • the optical system may be performed setting the degree of deflection depending on the position of the core C k.
  • deflecting prism 32a, 32b or the incident surface of 32 ' the angle of the exit surface, at each side, the same method as described in the second embodiment, To set the degree of deflection.
  • the pitch d of the diffraction gratings on the surfaces F k of the first diffractive optical system 34a and the second diffractive optical system 34b may be changed according to the position of the core C k .
  • FIG. 8 is a conceptual diagram showing an axial cross section of the coupling member 20, the fiber bundle 10, and the multicore fiber 1.
  • the coupling member 20 according to this modification has one end in contact with the fiber bundle 10 and the other end in contact with the multicore fiber 1.
  • the coupling member 20 is filled with a predetermined medium.
  • the predetermined medium is a medium other than air, and for example, quartz glass or BK7 is used.
  • the coupling member 20 and the fiber bundle 10 (multi-core fiber 1) are fixed to each other at their opposite end surfaces with an adhesive or the like.
  • the adhesive has a refractive index comparable to that of the core C (core Ca).
  • the coupling member 20 changes the mode field diameter of each light from each optical path (single core fiber 100) of the fiber bundle 10 and changes the interval of the light whose mode field diameter has been changed. Lead to each core (core C k ).
  • the mode field diameter refers to the diameter of light actually emitted from a certain target. For example, light passing through the core C of the single core fiber 100 slightly leaks to the cladding 101 side around the core C. Therefore, the light emitted from the single core fiber 100 is emitted not only from the core C but also from the cladding 101 around the core C. That is, the diameter of light emitted from the single core fiber 100 is larger than the diameter of the core C. This “diameter of light emitted from the single core fiber 100” is an example of a mode field diameter.
  • the coupling member 20 in the present modification includes a first optical system 21 and a second optical system 22.
  • the first optical system 21 changes the mode field diameter of each light incident from the single core fiber 100 and causes the light to enter the second optical system 22.
  • the second optical system 22 changes the interval of light incident from the first optical system 21 to match the interval of the cores C k of the multicore fiber 1.
  • the refractive index of the medium A2 constituting the lens portion of the first optical system 21 and the second optical system 22 is different from that of the medium A1 constituting the other portion.
  • the medium A1 is an example of a “first medium”.
  • the medium A2 is an example of a “second medium”.
  • the first optical system 21 and the second optical system 22 in this modification are integrally formed via the medium A1 (the first optical system 21 and the second optical system 22 are formed continuously). ).
  • Refractive index of the medium A1 is desirably equal material and the refractive index of the core C k of the refractive index or the multi-core fiber of the core C of single-core fiber 100.
  • the core C k of the multi-core fiber 1 is formed of a material in which germanium oxide (GeO 2 ) is added to quartz glass
  • germanium oxide GeO 2
  • the same material in which germanium oxide is added to quartz glass is used as the medium A1 (
  • another material having the same refractive index as the core C k may be used.
  • the first optical system 21 in this modification is an expansion optical system that expands the mode field diameter of each light from each single core fiber 100 of the fiber bundle 10.
  • the first optical system 21 includes a plurality of convex lens portions 21a arranged in an array.
  • the plurality of convex lens portions 21a are made of the medium A2, and are arranged in the medium A1. Since it is necessary to change the mode field diameter of each light from the fiber bundle 10, the plurality of convex lens portions 21 a is provided in the same number as the single core fibers 100 included in the fiber bundle 10.
  • the first optical system 21 (convex lens portion 21a) is disposed at a position where each principal ray Pr of light emitted from each end face Ca of the fiber bundle 10 enters perpendicularly to the surface of the corresponding convex lens portion 21a.
  • the convex lens portion 21a is disposed on the same optical axis as each core C).
  • the convex lens portion 21a has a diameter larger than the mode field diameter of the core C, and condenses light from the core C.
  • the plurality of convex lens portions 21a in this modification is an example of “a plurality of lenses”.
  • the second optical system 22 in this modification example is a reduction that leads to the cores C 1 to C 7 of the multi-core fiber 1 by narrowing the interval of the light from the first optical system 21 (a plurality of lights having an enlarged mode field diameter). It is an optical system.
  • the second optical system 22 is configured by a double-sided telecentric optical system including two convex lens portions (a convex lens portion 22a and a convex lens portion 22b). Convex lens part 22a and convex lens part 22b consist of medium A2, and are arranged in medium A1. The reason why only one set of the convex lens portion 22a and the convex lens portion 22b is provided is to change the interval of light from the plurality of convex lens portions 21a.
  • the second optical system 22 is disposed at a position where each principal ray Pr of the light from the first optical system 21 is perpendicularly incident on the end face E k of each core C k of the corresponding multi-core fiber 1.
  • each light emitted from each end face Ca enters the convex lens portion 21a with a predetermined mode field diameter while diffusing in the medium A1.
  • the principal ray Pr of each light emitted from the end face Ca is incident perpendicularly to the convex lens portion 21a.
  • Each light transmitted through the convex lens portion 21a forms an image at the image point IP with the mode field diameter being enlarged.
  • Each light transmitted through the convex lens portion 21a enters the convex lens portion 22a while diffusing in the medium A1 with the imaging point IP as a secondary light source.
  • the convex lens portion 22a and the convex lens portion 22b are formed as a both-side telecentric optical system. Accordingly, each of the principal rays Pr of light incident perpendicularly to the convex lens portion 22a passes through the medium A1 in a collimated state and enters the convex lens portion 22b. Each principal ray Pr of the light is emitted perpendicularly from the convex lens portion 22b in a state where the distance therebetween is narrowed, incident perpendicularly to the plurality of cores C k of the multi-core fiber 1 passes through the medium A1.
  • first optical system 21 and the second optical system 22 can be formed separately and combined to form the coupling member 20.
  • first optical system 21 and the second optical system 22 are respectively made of the medium A1 and the medium A2. Then, the end face of the first optical system 21 and the end face of the second optical system 22 are fixed with an adhesive, thereby forming an integral coupling member 20.
  • the adhesive has a refractive index comparable to that of the medium A1.
  • FIG. 9 is a conceptual diagram illustrating a cross section in the axial direction of the coupling member 20, the fiber bundle 10, and the multicore fiber 1.
  • a GRIN lens is used as the first optical system 21 and the second optical system 22 constituting the coupling member 20 shown in Modification 2 common to the first to third embodiments.
  • the coupling member 20 in this modification has a GRIN lens.
  • the GRIN lens is a refractive index distribution type lens that collects light by adjusting the refractive index distribution in the lens by bending the medium that constitutes the lens, and bending the diffused light.
  • the refractive index distribution can be adjusted by the ion exchange processing method.
  • a SELFOC lens (“SELFOC” is a registered trademark) can be used as the GRIN lens.
  • the first optical system 21 has a GRIN lens SL1.
  • the GRIN lens SL1 is formed of a medium whose refractive index is adjusted so as to change the mode field diameter of light from the fiber bundle 10 (single core fiber 100).
  • a plurality of GRIN lenses SL1 are provided corresponding to the number of single core fibers 100 forming the fiber bundle 10.
  • the GRIN lens SL1 is an example of a “first GRIN lens”.
  • each of the plurality of GRIN lenses SL1 in this modification includes a first optical member SL1a and a second optical member SL1b.
  • the first optical member SL1a is in contact with the fiber bundle 10 at one end, and the refractive index distribution is adjusted so as to collimate light that is incident from the single core fiber 100 and diffuses.
  • One end of the second optical member SL1b is in contact with the other end of the first optical member SL1a, and the refractive index distribution is adjusted so that the light collimated by the first optical member SL1a is converged.
  • the mode field diameter of the light (light at the imaging point IP) converged by the second optical member SL1b is larger than the mode field diameter of the light from the single core fiber 100.
  • the first optical member SL1a and the second optical member SL1b constitute an integral GRIN lens SL1 by being fixed by an adhesive or the like.
  • the adhesive has a refractive index comparable to that of the medium.
  • the second optical system 22 has a GRIN lens SL2.
  • the GRIN lens SL2 is formed of a medium whose refractive index is adjusted so as to change the interval of light whose mode field diameter has been changed. In this modification, only one GRIN lens SL2 is provided so that light from the plurality of GRIN lenses SL1 enters.
  • the GRIN lens SL2 is an example of a “second GRIN lens”.
  • the GRIN lens SL2 in the present modification includes a third optical member SL2a and a fourth optical member SL2b.
  • the third optical member SL2a has one end in contact with the other end of the second optical member SL1b, and the refractive index distribution is adjusted so as to collimate each light from the plurality of second optical members SL1b.
  • the fourth optical member SL2b has one end in contact with the other end of the third optical member SL2a and the other end in contact with the multi-core fiber 1.
  • the refractive index distribution of the fourth optical member SL2b is adjusted so as to converge the light from the third optical member SL2a.
  • the third optical member SL2a and the fourth optical member SL2b constitute an integral GRIN lens SL2 by being fixed by an adhesive or the like. Then, the second optical member SL1b and the third optical member SL2a are fixed with an adhesive or the like, so that the coupling member 20 is integrally formed.
  • the GRIN lens SL1 and the GRIN lens SL2 do not need to be formed of a plurality of optical members.
  • the GRIN lens SL1 and the GRIN lens SL2 only need to be formed from a medium whose refractive index is adjusted so that the respective functions can be achieved. That is, the GRIN lens SL1 and the GRIN lens SL2 may each be formed by one optical member. Alternatively, the GRIN lens SL1 and the GRIN lens SL2 can be formed from a single optical member.
  • each light emitted from each end face Ca is collimated by the first optical member SL1a and enters the second optical member SL1b.
  • the light incident on the second optical member SL1b is converged by the refractive index distribution of the medium constituting the second optical member SL1b.
  • Each of the lights transmitted through the second optical member SL1b forms an image at the image point IP with the mode field diameter being enlarged.
  • Each light transmitted through the second optical member SL1b is incident on the third optical member SL2a using the imaging point IP as a secondary light source (in this embodiment, the imaging point IP is between the GRIN lens SL1 and the GRIN lens SL2).
  • the refractive index of each GRIN lens is adjusted so that it is located at the boundary).
  • Each light incident on the third optical member SL2a passes through the third optical member SL2a in a state of being collimated based on the refractive index distribution of the medium constituting the third optical member SL2a, and enters the fourth optical member SL2b. . Then, the light incident on the fourth optical member SL2b is converged based on the refractive index distribution of the medium constituting the fourth optical member SL2b, and the plurality of cores C of the multi-core fiber 1 are narrowed with each other being narrowed. Incident to k .
  • FIG. 10 is a conceptual diagram illustrating a cross section in the axial direction of the coupling member 20, the fiber bundle 10, and the multicore fiber 1.
  • a plurality of fibers Fk are used as the first optical system 21 constituting the coupling member 20 and a GRIN lens SL2 is used as the second optical system 22 will be described.
  • the coupling member 20 in this modification includes a first optical system 21 and a second optical system 22.
  • One end of the fiber F k is in contact with the single core fiber 100 constituting the fiber bundle 10 and changes the mode field diameter of each light from the single core fiber 100.
  • the fiber F k includes a core C f that transmits light and a clad 3 that covers the core C f .
  • the diameter of the core C f at the incident end in contact with the single core fiber 100 is substantially the same as the diameter of the core C of the single core fiber 100.
  • the number of the fibers F k equal to the number of the single core fibers 100 constituting the fiber bundle 10 is provided.
  • the fiber F k has a different core diameter at the entrance end and the exit end. Specifically, the fiber F k is formed such that the diameter of the core C f at the exit end in contact with the GRIN lens SL2 is larger than the diameter of the core C f at the entrance end in contact with the single core fiber 100.
  • the light passing through the core C f of the fiber F k has a mode field diameter that increases as it approaches the exit end.
  • the fiber F k is manufactured by the following method, for example. First, heat is applied to a part of one fiber to cut the fiber. By performing the further heat treatment to the end face of the cut fiber may be a core diameter of one end to obtain a larger fiber F k than the core diameter of the other end.
  • the example in which the fiber F k constituting the first optical system 21 and the single core fiber 100 are separate is described.
  • a single core fiber 100 is manufactured. It is also possible to manufacture the core fiber 100 and the fiber Fk integrally. In this way, by producing integrally the single-core fiber 100 and fiber Fk, it becomes unnecessary alignment with a single core fiber 100 and the fiber F k.
  • the second optical system 22 in the present modification uses the GRIN lens SL2 shown in the third modification common to the first to third embodiments.
  • GRIN lens SL2 has one end in contact with the other end of the fiber F k, is formed from a medium refractive index is adjusted to change the spacing of a plurality of fibers F k light mode field diameter was changed in each.
  • Each of the lights incident on the GRIN lens SL2 is converged based on the refractive index distribution of the medium constituting the second optical system 22, and is spaced from each other with respect to the plurality of cores C k of the multicore fiber 1. Incident.
  • FIG. 11A is a diagram showing an end face of the coupling member 20.
  • FIG. 11B is a diagram illustrating an end face of the multi-core fiber 1.
  • FIG. 11C is a diagram showing an AA cross section in FIGS. 11A and 11B.
  • a fitting portion M ⁇ b> 1 is provided on the end surface of the coupling member 20 (the end surface on the side connected to the multi-core fiber 1).
  • a fitting portion M ⁇ b> 2 is provided on the end face 2 a (end face on the side connected to the coupling member 20) of the clad 2 of the multicore fiber 1.
  • three projections P 1 to P 3 corresponding to the hole H 1 to the hole H 3 are provided.
  • the size of the protrusion Pk is formed to be approximately the same as the size of the hole Hk .
  • the multicore fiber 1 with respect to the end surface of the coupling member 20 is connected by fitting so that the protrusions P k and the holes H k are fitted.
  • the position of the end face 1b is uniquely determined. That is, alignment adjustment in the rotation direction is not necessary. It is also possible to provide the fitting portion M2 on the end surface of the coupling member 20 and provide the fitted portion M1 on the end surface 2a of the clad 2.
  • the coupling member 20 has the GRIN lens SL1 in the second embodiment as the first optical system 21, and the both-side telecentric optical system (convex lens portion 22a, convex lens portion 22b) in the first embodiment as the second optical system 22. It is also possible to have.

Abstract

La présente invention concerne un système de couplage optique et un procédé de couplage l'utilisant, une réduction de l'efficacité de couplage pouvant être supprimée lors du couplage entre une fibre à plusieurs cœurs et un autre élément optique. La présente invention couple optiquement un élément optique et une fibre à plusieurs cœurs, et est placée entre une fibre à plusieurs cœurs dans laquelle plusieurs cœurs sont recouverts d'une gaine, et un élément optique qui est une pluralité de sources de lumière ou une pluralité d'éléments récepteurs de lumière ou un faisceau de fibres dans lequel plusieurs fibres à cœur simple sont regroupées. Le système de couplage optique est conçu de sorte que l'ouverture numérique de chaque lumière de la pluralité de lumières incidentes à partir d'un élément du côté incidence (qui est soit l'élément optique, soit la fibre à plusieurs cœurs), et l'ouverture numérique de chaque lumière de la pluralité de lumières émises vers un élément du côté émission (qui est l'autre de l'élément optique ou de la fibre à plusieurs cœurs) soient égales.
PCT/JP2012/071848 2011-09-01 2012-08-29 Système de couplage optique et procédé de couplage WO2013031836A1 (fr)

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WO2020245705A1 (fr) * 2019-06-03 2020-12-10 Alcon Inc. Alignement de faisceaux laser à longueurs d'onde multiples avec les cœurs d'une fibre multi-cœur
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JP7360694B2 (ja) * 2019-10-02 2023-10-13 株式会社中原光電子研究所 光接続装置
JP7270219B2 (ja) 2019-10-07 2023-05-10 パナソニックＩｐマネジメント株式会社 光合波器及びそれを用いた画像投影装置
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WO2014038514A1 (fr) * 2012-09-06 2014-03-13 株式会社オプトクエスト Fibre multicœur, et instrument de liaison optique pour fibre monomode
JPWO2014038514A1 (ja) * 2012-09-06 2016-08-08 株式会社 オプトクエスト マルチコアファイバとシングルモードファイバの光接続器
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US11822125B2 (en) 2018-09-18 2023-11-21 Mitsubishi Electric Corporation Multiplexing optical system
CN113167974A (zh) * 2018-12-25 2021-07-23 株式会社藤仓 连接器系统、光连接方法以及光连接部件
CN113167974B (zh) * 2018-12-25 2023-05-12 株式会社藤仓 连接器系统、光连接方法以及光连接部件
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US11402585B2 (en) * 2019-03-05 2022-08-02 Sumitomo Electric Industries, Ltd. Optical connection structure
WO2020245705A1 (fr) * 2019-06-03 2020-12-10 Alcon Inc. Alignement de faisceaux laser à longueurs d'onde multiples avec les cœurs d'une fibre multi-cœur
DE102022107005A1 (de) 2022-03-24 2023-09-28 Huber+Suhner Cube Optics Ag Optischer Multikoppler mit Korrekturelement und Herstellungsverfahren hierfür

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