Capillary for holding optical fiber, optical component, and optical switch

Abstract

One optical fiber holding capillary 5 used for an optical switch 1 including optical fibers 6a, 6b, a lens 3 or a prism, and a mirror 4, the optical fiber 6a being one or a plurality of input optical fibers, and the optical fibers 6b being a plurality of output optical fibers. The optical fiber holding capillary 5 comprises one or more input through-holes 5a in which the optical fiber 6a is inserted and fixed, and output through-holes 5b arranged in parallel with the one or more input through-holes 5a and in which the optical fibers 6b are inserted and fixed.

Description

Capillaries for holding optical fibers, optical components, and optical switches

[0001] The present invention relates to a capillary for holding an optical fiber, an optical component using the capillary, and an optical switch using the optical component.

[0002] One type of optical switch that is well known is one in which multiple optical fibers are held in a capillary, and optical fibers for input and output that are optically connected are selected from the multiple optical fibers to perform optical switching.

[0003] As an example, Patent Document 1 (see Figure 7) discloses a configuration in which a first capillary (called a ferrule in the document) is provided with an input through-hole for inserting and fixing one or more input optical fibers, and a second capillary is provided with an output through-hole for inserting and fixing multiple output optical fibers.

[0004] Furthermore, the same document describes that relative rotation between the first capillary and the second capillary optically connects one input optical fiber selected from one or more optical fibers inserted and fixed in the input through-hole to one output optical fiber selected from multiple optical fibers inserted and fixed in the output through-hole.

[0005] As another example, Patent Document 2 (see claim 1) discloses an optical switch that includes a capillary that arranges multiple (four) optical fibers in parallel on the same plane, a collimating lens, and a flat micromirror. The capillary in this document holds the four optical fibers along a V-groove and has a semicircular cross section (see paragraph

[0008] and Figure 2).

[0006] Furthermore, the document discloses that one input optical fiber and one output optical fiber are selected from the four optical fibers depending on the tilt of the planar micromirror, and the two selected optical fibers are optically connected.

[0007] International Publication No. 2023 / 181164 Japanese Patent Application Laid-Open No. 2004-70050

[0008] The configuration disclosed in Patent Document 1 has two capillaries arranged in series, which increases the overall length along their central axes, resulting in a large optical component in which all optical fibers are held by the capillaries.

[0009] The configuration disclosed in Patent Document 2 uses a single capillary, but since multiple optical fibers are arranged on the same plane of the capillary, the length of the capillary in the direction of arrangement of the optical fibers becomes long, which also results in an optical component having all the optical fibers held in the capillary becoming large.

[0010] In view of the above, an object of the present invention is to make compact optical components for an optical switch in which all optical fibers are held in capillaries.

[0011] (1) A first aspect of the present invention, which has been invented to solve the above-mentioned problems, is a capillary for holding an optical fiber used in an optical switch including an optical fiber, a lens or prism, and a mirror, characterized in that one capillary for holding an optical fiber has an input through-hole for inserting and fixing one or more input optical fibers, and an output through-hole arranged parallel to the input through-hole and for inserting and fixing one or more output optical fibers.

[0012] According to this configuration, by providing an input through hole and an output through hole in one optical fiber holding capillary, there is no need to provide two capillaries for input and output. This makes the optical component for the optical switch, which holds all optical fibers in the capillaries, compact. Moreover, even if the total number of input through holes and output through holes is large, these through holes can be arranged three-dimensionally in one capillary. Furthermore, multiple optical fibers can be inserted and fixed together in one through hole. Either of these allows the optical component to be made more compact than when all optical fibers are arranged in parallel on the same plane.

[0013] (2) In the configuration of (1) above, one input through hole may be provided for inserting and fixing one input optical fiber, and multiple output through holes may be provided for inserting and fixing multiple output optical fibers separately.

[0014] In this way, all of the input optical fibers and output optical fibers are inserted and fixed into separate through holes, so that all of the optical fibers can be firmly held in the capillary, thereby improving durability, etc.

[0015] (3) In the configuration of (1) or (2), the plurality of output through holes may be arranged concentrically around the input through hole. Here, "arranged concentrically" includes not only the case where the centers of all the output through holes are located on a single circle, but also the case where the centers of the through holes are offset from the single circle within a range where the movement trajectory of one through hole when it moves along the single circle is included in the movement trajectory of the other through holes when they move along the single circle.

[0016] In this way, the optical path lengths from the input optical fiber inserted and fixed in the input through hole to all of the output optical fibers inserted and fixed in the multiple output through holes can be made the same, thereby suppressing variations in optical characteristics such as optical loss that may occur along the optical path from the input optical fiber to the output optical fiber, and enabling appropriate light switching.

[0017] (4) In any of the above configurations (1) to (3), the plurality of output through holes may be arranged at equal angular intervals.

[0018] In this way, when selecting one output fiber to be optically connected to one input optical fiber from among the multiple output optical fibers inserted and fixed in the multiple output through holes, it is sufficient to change the tilt (angle) of the mirror evenly, which simplifies the control for changing the tilt of the mirror.

[0019] (5) In any of the configurations (1) to (4) above, the cross-sectional shape of the output through-hole is preferably circular. Here, the "cross-sectional shape of the hole" refers to the shape of the hole in a cross section perpendicular to the penetration direction of the hole (the same applies hereinafter).

[0020] This makes it easier to insert an optical fiber, which typically has a circular cross-sectional shape, and facilitates positioning, unlike when the cross-sectional shape of the hole is, for example, rectangular. Furthermore, chipping, which may occur in the output through-hole when inserting the output optical fiber into the output through-hole, can be avoided. Here, when the through-holes have the same shape, the variation in the hole diameter of each through-hole is preferably within 5%, more preferably within 3%, and even more preferably within 1%. On the other hand, the output through-holes may be similar to each other. In this case, this effect can be obtained even if the cross-sectional shape of the hole is not circular (perfect circle) but is elliptical.

[0021] (6) In any of the configurations (1) to (5) above, it is preferable that the cross section of the input through hole has a circular shape.

[0022] This makes it easier to insert an optical fiber, which is usually circular in cross section, unlike when the cross section of the hole is rectangular, and also simplifies positioning. Furthermore, chipping, which may occur in the input through hole when inserting the input optical fiber into the input through hole, can be avoided. Note that this effect can also be achieved even if the cross section of the hole is not circular (perfectly circular), but is elliptical.

[0023] (7) In the configuration of (1) above, one input through-hole for inserting and fixing one input optical fiber, or one or more input through-holes for inserting and fixing multiple input optical fibers together, and one or more output through-holes for inserting and fixing multiple output optical fibers together may be provided.

[0024] In this way, a large number of output optical fibers (e.g., 10 or more, preferably 15 or more) can be inserted and fixed into a small number of output through holes (e.g., 1 to 5), and the capillary can hold a large number of output optical fibers efficiently and accurately.

[0025] (8) In the configuration of (7) above, the output through hole may have a larger cross-sectional area than the input through hole. Here, the "cross-sectional area" refers to the area of ​​the hole in a cross section perpendicular to the penetration direction of the hole (the same applies hereinafter).

[0026] In this way, the input optical fibers, which are preferably a small number, and the output optical fibers, which are preferably a large number, can be properly inserted and fixed in the respective through holes.

[0027] (9) In the configuration of (7) or (8) above, there may be provided one input through hole for inserting and fixing one input optical fiber, the cross-sectional shape of the input through hole being circular, and the cross-sectional shape of the output through hole being rectangular. Here, the "shape of the cross-section of the hole" refers to the shape of the hole in a cross section perpendicular to the penetration direction of the hole (the same applies hereinafter). In this specification, the term "rectangle" includes a square.

[0028] In this way, one input optical fiber and a plurality of output optical fibers can be inserted and fixed into the input through-hole and the output through-hole efficiently and accurately.

[0029] (10) In any of the configurations (1) to (9) above, the input through hole and the output through hole may have a tapered portion that gradually widens toward one of the openings formed at both ends of each.

[0030] In this way, when inserting and fixing each optical fiber into each through hole, the optical fiber can be inserted from the tapered portion of each through hole, which makes the insertion work easier and improves workability. Furthermore, after the insertion work is completed, adhesive can be filled into the gap between the tapered portion and the optical fiber and allowed to harden, thereby firmly fixing each optical fiber in each through hole.

[0031] (11) In any of the configurations (1) to (10) above, a communication portion may be provided that connects the input through hole and the output through hole at the end on one of the opening sides.

[0032] In this way, when performing the above-mentioned insertion work, the workability is further improved by inserting each optical fiber through the communicating portion. Furthermore, after the insertion work is completed, each optical fiber can be more firmly fixed in each through hole by filling the gap between the communicating portion and the optical fiber with adhesive and allowing it to harden.

[0033] (12) A second aspect of the present invention, which was invented to solve the above-mentioned problems, is an optical component used in an optical switch, which includes an optical fiber, a lens or prism, and a mirror, characterized in that an input through hole and an output through hole arranged parallel to the input through hole are provided in a single optical fiber holding capillary that holds the optical fiber, and one or more input optical fibers are inserted and fixed in the input through hole, and multiple output optical fibers are inserted and fixed in the output through hole.

[0034] With an optical component having such a configuration, substantially the same effects as those obtained with the configuration (1) above can be obtained.

[0035] (13) A third aspect of the present invention, which has been invented to solve the above problems, is an optical switch including an optical fiber, an optical fiber holding capillary, a lens or prism, and a mirror, wherein one optical fiber holding capillary is provided with an input through hole and an output through hole arranged parallel to the input through hole, one or more input optical fibers are inserted and fixed into the input through hole, and multiple output optical fibers are inserted and fixed into the output through hole, and one input optical fiber and one output optical fiber are selected according to the inclination of the mirror, and the selected optical fibers are optically connected via the lens or prism.

[0036] According to the optical switch having such a configuration, substantially the same effects as those obtained in the case of the configuration (1) above can be obtained.

[0037] (14) A fourth aspect of the present invention, which has been invented to solve the above problems, is a capillary for holding an optical fiber used in an optical switch including an optical fiber, a lens or a prism, and a mirror, characterized in that one capillary for holding an optical fiber has one through-hole in at least one location for inserting and fixing a total of three or more input optical fibers and output optical fibers together.

[0038] With this configuration, the input optical fiber and the output optical fiber are inserted and fixed together into a single through-hole, which makes it possible to further compact the optical component. Also, since the optical path from the input optical fiber to the output optical fiber can be shortened, variations in optical characteristics such as optical loss that may occur along the optical path can be suppressed, enabling appropriate light switching.

[0039] (15) In the configuration of (14) above, one through hole is for inserting and fixing a total of three input optical fibers and three output optical fibers together, and the cross-sectional shape of one through hole may be such that the distances between the centers of all three optical fibers are equal and the total of three optical fibers are housed in a dense state. Here, "housed in a dense state" means that all optical fibers are in a dense state (contact or nearly contact) with each other and that all optical fibers are in a dense state (contact or nearly contact) with the inner surface of the through hole.

[0040] In this way, any one of the three optical fibers can be used for input (or output), improving the convenience of using the capillary. Furthermore, since the three optical fibers are accommodated in one through-hole with the same center-to-center distance, the optical path lengths from the input optical fiber to the remaining two output optical fibers can be made the same, thereby reducing variations in optical characteristics such as optical loss. Furthermore, since the three optical fibers are accommodated in one through-hole in a dense state, the optical path from the input optical fiber to the output optical fiber can be further shortened, thereby more reliably reducing variations in optical characteristics such as optical loss.

[0041] (16) In the configuration of (15) above, the cross section of the hole may have an equilateral triangular shape.

[0042] This is advantageous in that a total of three optical fibers can be accommodated in a single through hole in the state (15) above, and it also effectively prevents the optical fibers from shifting in their circumferential positions.

[0043] (17) In the configuration of (14) above, one through hole is for inserting and fixing one input optical fiber and multiple output optical fibers arranged on the outer periphery of the one input fiber together, and the cross-sectional shape of the one through hole may be such that the distances between the centers of the one input optical fiber and the multiple optical fibers are all equal and the one input optical fiber and the multiple optical fibers are accommodated in a dense state. Here, "accommodated in a dense state" means that all the optical fibers are in a dense state (contact or nearly contact) with each other and that all the multiple output optical fibers are in a dense state (contact or nearly contact) with the inner surface of the through hole.

[0044] In this way, one input optical fiber and multiple optical fibers are accommodated in one through hole with the same center-to-center distance, so the optical path lengths from the input optical fiber to all output optical fibers can be made the same, and variations in optical characteristics such as optical loss can be suppressed. Furthermore, one input optical fiber and multiple output optical fibers are accommodated in one through hole in a dense state, so the optical paths from the input optical fiber to all output optical fibers can be made even shorter, and variations in optical characteristics such as optical loss can be more reliably suppressed.

[0045] (18) A fifth aspect of the present invention, which has been invented to solve the above problems, is an optical component used in an optical switch, which includes an optical fiber, an optical fiber holding capillary, a lens or prism, and a mirror, characterized in that one through-hole is provided in at least one location in one optical fiber holding capillary, and a total of three or more input optical fibers and output optical fibers are inserted and fixed together in one through-hole.

[0046] With an optical component having such a configuration, substantially the same effects as those obtained with the configuration (14) above can be obtained.

[0047] (19) A sixth aspect of the present invention, which has been invented to solve the above problems, is an optical switch including an optical fiber, an optical fiber holding capillary, a lens or prism, and a mirror, characterized in that one through-hole is provided in at least one location in one optical fiber holding capillary, a total of three or more input optical fibers and output optical fibers are inserted and fixed into one through-hole, one input optical fiber and one output optical fiber are selected according to the inclination of the mirror, and the selected optical fibers are optically connected via the lens or prism.

[0048] According to the optical switch having such a configuration, substantially the same effects as those obtained in the case of the configuration (14) above can be obtained.

[0049] According to the present invention, the optical components for an optical switch, in which all optical fibers are held in capillaries, can be made compact.

[0050] 1. A perspective view schematically showing the configuration of a main part of an optical switch according to a first embodiment of the present invention. A cross-sectional view showing the general configuration of an optical switch according to the first embodiment of the present invention. A front view of an optical fiber holding capillary according to the first embodiment of the present invention. A cross-sectional view taken along line CC of FIG. 3. A cross-sectional view of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to the first embodiment of the present invention. A front view showing a first modified example of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to the first embodiment of the present invention. A cross-sectional view showing the main part of a first modified example of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to the first embodiment of the present invention. A front view showing a second modified example of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to the first embodiment of the present invention. A cross-sectional view taken along line DD of FIG. 8. A front view of an optical fiber holding capillary according to a second embodiment of the present invention. A cross-sectional view taken along line E-E of FIG. 10. A front view of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to the second embodiment of the present invention. A cross-sectional view taken along line F-F of FIG. 12. 14. A front view showing a first modified example of an optical component made by holding a plurality of optical fibers in an optical fiber holding capillary according to a second embodiment of the present invention. A cross-sectional view taken along line G-G in FIG. 14. A front view showing a second modified example of an optical component made by holding a plurality of optical fibers in an optical fiber holding capillary according to the second embodiment of the present invention. A cross-sectional view taken along line H-H in FIG. 16. A front view of an optical fiber holding capillary according to a first example of a third embodiment of the present invention. A front view of an optical component made by holding a plurality of optical fibers in an optical fiber holding capillary according to a first example of a third embodiment of the present invention. A front view showing a main part of an optical component made by holding a plurality of optical fibers in an optical fiber holding capillary according to a first example of a third embodiment of the present invention. A front view showing a main part of an optical component made by holding a plurality of optical fibers in an optical fiber holding capillary according to a first example of a third embodiment of the present invention.1 is a front view showing a main part of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to a first example (second modified example) of the third embodiment of the present invention; FIG. 2 is a front view showing a main part of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to a first example (third modified example) of the third embodiment of the present invention; FIG. 3 is a front view of an optical fiber holding capillary according to a second example of the third embodiment of the present invention; FIG. 4 is a front view of an optical fiber holding capillary according to a second example of the third embodiment of the present invention; FIG. 5 is a front view of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to a second example of the third embodiment of the present invention; FIG. 6 is a front view of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to a second example (modified example) of the third embodiment of the present invention; FIG. 7 is a front view of an optical component formed by holding a plurality of optical fibers in an optical fiber holding capillary according to a third example of the third embodiment of the present invention;

[0051] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical fiber holding capillary and an optical switch according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0052] <First embodiment> Fig. 1 is a perspective view that schematically shows the configuration of a main part of an optical switch 1 according to a first embodiment of the present invention, and Fig. 2 is a cross-sectional view that shows the general configuration of the optical switch 1. For convenience, in the following description, the direction of arrow A shown in Fig. 1 and Fig. 2 will be referred to as the front side, and the direction of arrow B shown in Fig. 1 and Fig. 2 will be referred to as the rear side (the same applies to other figures with arrows A and B).

[0053] 1 and 2, the optical switch 1 includes an optical component 2, a lens 3, and a mirror 4. The lens 3 is disposed in front of the optical component 2, and the mirror 4 is disposed in front of the lens 3.

[0054] FIG. 3 is a front view of an optical fiber holding capillary 5 (hereinafter simply referred to as capillary 5), which is a component of the optical component 2, and FIG. 4 is a cross-sectional view taken along line CC in FIG.

[0055] 3 and 4, the capillary 5 is cylindrical and made of glass. The glass is preferably borosilicate glass, but other glass may be used, such as quartz glass, soda lime glass, aluminosilicate glass, alkali-free glass, Li ２ O-Al ２ O ３ -SiO ２ (LAS)-based crystallized glass may also be used.

[0056] The capillary 5 has a single input through-hole 5a at its center, extending along the central axis X. A plurality of output through-holes 5b (eight in the illustrated example) are provided on the outer periphery of the input through-hole 5a in the capillary 5, and are arranged in parallel to the input through-hole 5a.

[0057] The plurality of output through holes 5b are arranged concentrically around the input through hole 5a (strictly speaking, the central axis X). Furthermore, the plurality of output through holes 5b are arranged at equal angular intervals (45° intervals in the illustrated example). In the example shown in FIG. 3, the distance L1 between the input through hole 5a and the output through hole 5b is equal to the distance L2 from the output through hole 5b to the outer peripheral surface 5c of the capillary 5. If the distance L2 is 0.15 to 7 times the distance L1, it is possible to avoid a decrease in the strength of the capillary 5 due to the presence of the input through holes 5a and the output through holes 5b.

[0058] The capillary 5 is fabricated by, for example, a redraw method after forming a through hole having a desired cross-sectional shape in a glass preform by machining or the like. In the redraw method, the glass preform is heated and a part of it is stretched, thereby forming the capillary 5 having the desired through hole (the same applies to the second and third embodiments described below).

[0059] Fig. 5 is a cross-sectional view including the central axis X of the optical component 2. As shown in Fig. 5, the optical component 2 has one input optical fiber 6a and multiple output optical fibers 6b held in a capillary 5. More specifically, one input optical fiber 6a is inserted and fixed into one input through-hole 5a of the capillary 5, and multiple output optical fibers 6b are inserted and fixed into multiple output through-holes 5b, respectively. Front ends 6ax, 6bx of all the optical fibers 6a, 6b are located on the plane formed by a front end face 5d of the capillary 5 (hereinafter referred to as the front end face 5d).

[0060] As shown in FIG. 2 , the mirror 4 is configured so that its tilt can be freely changed with its center 4 a as a fulcrum. Therefore, the input light Za emitted from the input optical fiber 6 a of the optical component 2 is reflected by the mirror 4, and the reflected light Zb is incident on any one of the output optical fibers 6 b selected from the plurality of optical fibers 6 b depending on the tilt of the mirror 4. Furthermore, both the input light Za and the reflected light Zb pass through the lens 3. The lens 3 is configured to focus the reflected light Zb onto any one of the plurality of output optical fibers 6 b. These functions allow one input optical fiber 6 a and any one selected output optical fiber 6 b to be optically connected via the lens 3. The center 3 a of the lens 3 and the center 4 a of the mirror 4 are both located on the central axis X of the capillary 5 (see FIG. 1 ).

[0061] With this configuration, the optical path lengths from one input optical fiber 6 a to multiple output optical fibers 6 b can be made the same, which reduces variations in optical characteristics such as optical loss that may occur along the optical path from the input optical fiber 6 a to the output optical fiber 6 b, making it possible to perform appropriate light switching.

[0062] Furthermore, since the multiple output optical fibers 6b are arranged at equal angular intervals, when selecting one output optical fiber 6b to be optically connected to the input optical fiber 6a, it is sufficient to uniformly change the tilt (angle) of the mirror 4. This allows for easy control of changing the tilt of the mirror 4.

[0063] In the first embodiment, by providing an input through hole 5a and an output through hole 5b in one capillary 5, there is no need to provide two capillaries, one for input and one for output. This makes the optical component 2 more compact. Moreover, even if the total number of input through holes 5a and output through holes 5b is large, these through holes 5a, 5b can be arranged three-dimensionally in one capillary 5, so the optical component 2 can be made more compact than when many optical fibers are arranged in parallel on the same plane.

[0064] 6 and 7 show an optical component 2 according to a first modified example of the first embodiment, with Fig. 6 being a front view of the optical component 2 and Fig. 7 being a cross-sectional view of a main portion of the optical component 2. As shown in these figures, in this optical component 2, all of the input through holes 5a and output through holes 5b formed in the capillaries 5 have tapered portions 5f on the rear end faces 5e (hereinafter referred to as rear end faces 5e) of the capillaries 5. The diameters of the tapered portions 5f gradually increase toward the openings 5g on the rear end face 5e side of the capillaries 5. The tapered portions 5f are formed, for example, by etching.

[0065] According to this configuration, when inserting and fixing the optical fibers 6a, 6b into the through holes 5a, 5b, the optical fibers 6a, 6b can be inserted through the tapered portions 5f of the through holes 5a, 5b, which facilitates the insertion. After the insertion is completed, adhesive can be filled into the gap between the tapered portions 5f and the optical fibers 6a, 6b and allowed to harden, thereby firmly fixing the optical fibers 6a, 6b to the through holes 5a, 5b. The tapered portions 5f may be formed on the front end face 5d of the capillary 5.

[0066] 8 and 9 show an optical component 2 according to a second modification of the first embodiment, with FIG. 8 being a front view of the optical component 2 and FIG. 9 being a cross-sectional view taken along line D-D in FIG. 8. As shown in these figures, the optical component 2 includes a communicating portion 5h that connects all of the input through holes 5a and output through holes 5b provided in the capillary 5 at the end on the rear end face 5e side of the capillary 5. The communicating portion 5h is connected to the tapered portion 5f described above. The contour shape of the outer edge 5j of the communicating portion 5h is circular or approximately circular (see FIG. 8). The communicating portion 5h may also be formed on the front end face 5d side of the capillary 5. The communicating portion 5h may be formed by, for example, etching.

[0067] With this configuration, the volume of the communicating portion 5 h is larger than the volume of the tapered portion 5 f, so that when performing the above-mentioned insertion operation, the optical fibers 6 a, 6 b can be inserted through the communicating portion 5 h, thereby further improving workability. Furthermore, after the insertion operation is completed, adhesive can be filled into the gaps between the communicating portion 5 h and the optical fibers 6 a, 6 b and allowed to harden, thereby more firmly fixing the optical fibers 6 a, 6 b to the through holes 5 a, 5 b.

[0068] The first embodiment of the present invention has been described above, but this first embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present invention.

[0069] For example, in the first embodiment described above, the input through hole 5a was formed at the center of the capillary 5, but the input through hole 5a may be provided at a position off the center of the capillary 5, and multiple output through holes 5b may be arranged concentrically around this input through hole 5a.

[0070] In the first embodiment, the plurality of output through holes 5b are arranged concentrically around the input through hole 5a, but the arrangement of the input through holes 5a and the plurality of output through holes 5b may be different. In this case, the optical switch 1 shown in Figure 2 must have a different configuration for changing the tilt of the mirror 4 and a different configuration for the lens 3 from those shown in the figure. Even in this case, the input light Za emitted from one input optical fiber 6a is transmitted through the lens 3 and reflected by the mirror 4, and the reflected light Zb is transmitted through the lens 3 and focused on any of the plurality of output optical fibers 6b.

[0071] In the first embodiment, the optical switch 1 is described as including a lens 3 and a mirror 4. In this case, the lens 3 is preferably a lens array, but may be other lenses, and the mirror 4 is preferably a mirror array, but may be other mirrors (the same applies to the second and third embodiments described below).

[0072] In the first embodiment, one input through hole 5a is provided, but multiple input through holes 5a may be provided. In this case, one of the multiple input optical fibers 6a and one of the multiple output optical fibers 6b are selected depending on the tilt of the mirror 4. Also, although eight output through holes 5b are provided, the number of output through holes 5b is not limited as long as it is two or more. In these cases, it is preferable that the number of input through holes 5a is smaller than the number of output through holes 5b. In these cases, as in the above, the configuration for changing the tilt of the mirror 4 and the configuration of the lens 3 must be different from those in the example shown in FIG. 2.

[0073] In the first embodiment, the cross-sectional shape of the input through-hole 5a and the output through-hole 5b is circular, but it may be other shapes such as polygonal.

[0074] In the first embodiment, the lens 3 is used as a component of the optical switch 1, but a prism may be used instead. In this case, a prism array is preferable as the prism, but other prisms may also be used (the same applies to the second and third embodiments described below).

[0075] Second Embodiment Fig. 10 is a front view of a capillary 5 according to a second embodiment of the present invention, and Fig. 11 is a cross-sectional view taken along line E-E in Fig. 10. As shown in these figures, the capillary 5 is provided with one input through hole 5a and one output through hole 5b. The cross-sectional shape of the input through hole 5a is circular, and the cross-sectional shape of the output through hole 5b is rectangular. The cross-sectional area of ​​the output through hole 5b is larger than that of the input through hole 5a; for example, the former is 5 to 20 times larger than the latter.

[0076] 10, when an imaginary line M1 passing through the center (central axis X) of the capillary 5 is drawn, the input through holes 5a and the output through holes 5b are arranged on this imaginary line M1 at a distance from each other across the center X. Furthermore, the input through holes 5a and the output through holes 5b are symmetrical on both sides of this imaginary line M1.

[0077] Fig. 12 is a front view of the optical component 2 in which the above-mentioned capillary 5 holds an input optical fiber 6a and an output optical fiber 6b, and Fig. 13 is a cross-sectional view taken along line F-F in Fig. 12. As shown in these figures, one input optical fiber 6a is inserted and fixed into the input through-hole 5a, and multiple (18 in the illustrated example) output optical fibers 6b are inserted and fixed together into the output through-hole 5b. The multiple output optical fibers 6b are arranged in a straight line in the horizontal direction (six in the illustrated example), and in a straight line in the vertical direction perpendicular to the horizontal direction (three in the illustrated example).

[0078] When an optical component 2 having such a configuration is used, the configuration for changing the tilt of the mirror 4 and the configuration of the lens 3 must be different from those shown in the figure in the optical switch 1 shown in Fig. 2. In this case as well, the input light Za emitted from one input optical fiber 6a passes through the lens 3 and is reflected by the mirror 4, and the reflected light Zb passes through the lens 3 and is focused on any one of the multiple output optical fibers 6b.

[0079] According to this configuration, compared to the first embodiment, a larger number of output optical fibers 6b can be held efficiently in the capillary 5. Furthermore, since the cross section of the output through hole 5b has a rectangular shape, a larger number of output optical fibers 6b can be held efficiently.

[0080] 14 and 15 show an optical component 2 according to a first modified example of the second embodiment, with Fig. 14 being a front view of the optical component 2 and Fig. 15 being a cross-sectional view taken along line G-G in Fig. 14. As shown in these figures, in this optical component 2, the input through-hole 5a and the output through-hole 5b provided in the capillary 5 each have tapered portions 5k and 5m on the rear end face 5e side of the capillary 5. These tapered portions 5k and 5m gradually widen toward the openings 5n and 5p on the rear end face 5e side of the capillary 5.

[0081] According to this configuration, when inserting and fixing the optical fibers 6a, 6b into the through holes 5a, 5b, the optical fibers 6a, 6b can be inserted through the tapered portions 5k, 5m of the through holes 5a, 5b, making the insertion process easier. In particular, the insertion process can be easily performed when inserting multiple output optical fibers 6b into the output through hole 5b at once. After the insertion process is completed, adhesive can be filled into the gaps between the tapered portions 5k (5m) and the optical fibers 6a (6b) and allowed to harden, thereby firmly fixing the optical fibers 6a, 6b to the through holes 5a, 5b. The tapered portions 5k, 5m may be formed on the front end face 5d of the capillary 5.

[0082] 16 and 17 show an optical component 2 according to a second modification of the second embodiment, with FIG. 16 being a front view of the optical component 2 and FIG. 17 being a cross-sectional view taken along line H-H in FIG. 16. As shown in these figures, the optical component 2 includes a communication portion 5r that connects the input through-hole 5a and the output through-hole 5b formed in the capillary 5 at the end on the rear end face 5e side of the capillary 5. The communication portion 5r is connected to the tapered portions 5k and 5m described above. Note that the communication portion 5r may also be formed on the front end face 5d side of the capillary 5.

[0083] With this configuration, the volume of the communicating portion 5r is larger than the volume of the tapered portions 5k and 5m. Therefore, when performing the insertion operation, the optical fibers 6a and 6b are inserted through the communicating portion 5r, which further improves workability. In particular, workability is further improved when inserting multiple output optical fibers 6b into the output through-hole 5b at once. Furthermore, after the insertion operation is completed, adhesive can be filled in the gaps between the communicating portion 5r and the optical fibers 6a and 6b and allowed to harden, thereby more firmly fixing the optical fibers 6a and 6b to the through-holes 5a and 5b.

[0084] The second embodiment of the present invention has been described above, but the second embodiment is not limited to this and can be modified in various ways without departing from the spirit of the present invention.

[0085] For example, in the second embodiment described above, one input through hole 5a is formed in the capillary 5 for inserting and fixing one input optical fiber 6a, but multiple input through holes 5a may be provided for separately inserting and fixing multiple (e.g., 2 to 5) input optical fibers 6a, or one or multiple input through holes 5a may be provided for collectively inserting and fixing multiple input optical fibers 6a.

[0086] In the second embodiment, one output through-hole 5b is provided in the capillary 5 for inserting and fixing a plurality of output optical fibers 6b together, but a plurality of output through-holes 5b may be provided for inserting and fixing a plurality of output optical fibers 6b together.

[0087] In the second embodiment, the number of output optical fibers 6b inserted and fixed in the output through holes 5b is 18, but the number is not particularly limited as long as it is three or more.

[0088] <Third Embodiment> Fig. 18 is a front view of a capillary 5 according to a first example of a third embodiment of the present invention. As shown in the figure, this capillary 5 has one through-hole 7 in the center. The cross-sectional shape of this through-hole 7 is an equilateral triangle. A total of three input optical fibers 6a and output optical fibers 6b are inserted and fixed into this through-hole 7. The capillary 5 has a cylindrical shape (the same applies to the second, third, and fourth examples described below).

[0089] 19 is a front view showing an optical component 2 in which three optical fibers 6a, 6b having the same diameter are housed in the through hole 7 of the capillary 5. The three optical fibers 6a, 6b are housed in a tightly packed state in the through hole 7. Therefore, as shown enlarged in FIG. 20, all three optical fibers 6a, 6b are in a tightly packed state (contacting or nearly contacting) with each other, and all three optical fibers 6a, 6b are in a tightly packed state (contacting or nearly contacting) with the inner surface 7a of the through hole 7. Note that the inside of the through hole 7 may be filled with adhesive, but even in this case, the three optical fibers 6a, 6b are housed in a tightly packed state in the through hole 7.

[0090] When an optical component 2 having such a configuration is used, the configuration for changing the tilt of the mirror 4 and the configuration of the lens 3 must be different from those shown in the figure in the optical switch 1 shown in Fig. 2. Even in this case, the input light Za emitted from one input optical fiber 6a passes through the lens 3 and is reflected by the mirror 4, and the reflected light Zb passes through the lens 3 and is focused on either of the two output optical fibers 6b.

[0091] 19 and 20, one optical fiber in the upper row of the three optical fibers 6a, 6b is the input optical fiber 6a, and the two optical fibers in the lower row are the output optical fibers 6b, but any one optical fiber in the lower row may be the input optical fiber 6a, and the remaining two optical fibers may be the output optical fibers 6b. In this case, as shown in Fig. 20, regardless of which optical fiber is the input optical fiber 6a, the distance L3 between the centers of all three optical fibers 6a, 6b is the same.

[0092] The capillary 5 and optical component 2 having the above-described configuration provide the following advantages. Specifically, since the input optical fiber 6a and the output optical fiber 6b are inserted and fixed together in a single through-hole 7, the capillary 5 and the optical component 2 can be made even more compact. Also, any one of the three optical fibers 6a, 6b can be used for input (or output), improving the convenience of using the capillary 5 and the optical component 2. Furthermore, since the three optical fibers 6a, 6b are housed in a single through-hole with the same center-to-center distance L3, the optical path lengths from the input optical fiber 6a to the remaining two output optical fibers 6b can be made the same, thereby reducing variations in optical characteristics such as optical loss. Furthermore, since the three optical fibers 6a, 6b are housed in a single through-hole 7 in a densely packed state, the optical path from the input optical fiber 6a to the output optical fiber 6b can be further shortened, thereby more reliably reducing variations in optical characteristics such as optical loss. In addition, since the cross section of the through-hole 7 has an equilateral triangular shape, the three optical fibers 6a and 6b are less likely to be misaligned in the circumferential direction (direction of arrow J).

[0093] 21 and 22 show variations of the cross-sectional shape of the through hole 7 based on an equilateral triangle. In FIG. 21 , three corners of the equilateral triangle are removed along a straight line 7ax, while in FIG. 22 , three corners of the equilateral triangle are removed along a curved line (an arc line in the illustrated example) 7ay. In this case, the removed lines (straight or curved lines) 7ax and 7ay may be spaced apart from the optical fibers 6a and 6b. Therefore, these equilateral triangle-based shapes may include three straight lines that intersect at 60° angles at three locations and contact two optical fibers 6a and 6b, respectively. This also achieves the same effects as described above. Furthermore, as shown in FIG. 23 , the cross-sectional shape of the through hole 7 may be circular (perfectly circular). However, such a circular shape may easily cause misalignment of the three optical fibers 6a and 6b in the circumferential direction (direction of arrow J), but this does not apply when adhesive is filled into the through hole 7.

[0094] 24 is a front view of a capillary 5 according to a second example of the third embodiment of the present invention. As shown in the figure, the cross section of one through-hole 7 provided in the center of this capillary 5 is a regular hexagon. A total of seven input optical fibers 6a and output optical fibers 6b are inserted and fixed into this through-hole 7.

[0095] FIG. 25 is a front view showing an optical component 2 in which seven optical fibers 6a, 6b having the same diameter are housed in the through hole 7 of the capillary 5. In this second example, one input optical fiber 6a is disposed in the center of the through hole 7, and six output optical fibers 6b are disposed around it. In this second example, the seven optical fibers 6a, 6b are housed in a tightly packed state in the through hole 7. Therefore, as shown enlarged in FIG. 26, all seven optical fibers 6a, 6b are in a tightly packed state (contacting or nearly contacting) with each other, and all six output optical fibers 6b are in a tightly packed state (contacting or nearly contacting) with the inner surface 7a of the through hole 7. Furthermore, the distance L4 between the centers of the one input optical fiber 6a and the six output optical fibers 6b is the same.

[0096] With the capillary 5 and optical component 2 configured as described above, the optical path lengths from one input optical fiber 6a to six output optical fibers 6b can be made uniform, thereby reducing variations in optical characteristics such as optical loss. Furthermore, since a total of seven optical fibers 6a and 6b are densely packed in one through-hole 7, the optical path from the input optical fiber 6a to the output optical fiber 6b can be shortened, further reducing variations in optical characteristics such as optical loss. In addition, because the cross-sectional shape of the through-hole 7 is a regular hexagon, misalignment of the seven optical fibers 6a and 6b in the circumferential direction (direction of arrow J) is unlikely to occur. In this second example, the cross-sectional shape of the hole may be changed from a regular hexagon, in the same manner as described in the first example. Furthermore, as shown in FIG. 27 , the cross-sectional shape of the through-hole 7 may be circular (perfect circle). However, when the through hole 7 is made circular in this manner, it becomes easier for the seven optical fibers 6a, 6b to become misaligned in the circumferential direction (direction of arrow J), but this is not the case when adhesive is filled inside the through hole 7.

[0097] FIG. 28 is a front view of an optical component 2 including a capillary 5 according to a third example of the third embodiment of the present invention. As shown in the figure, the cross-sectional shape of one through-hole 7 provided in the center of the capillary 5 is a regular pentagon. In the optical component 2, one input optical fiber 6a with a relatively small diameter and five output optical fibers 6b with relatively large diameters arranged on the outer periphery of the input optical fiber 6a are inserted and fixed in the one through-hole 7. These six optical fibers 6a, 6b are densely packed in the through-hole 7 in the same manner as in the second example. In this third example, as in the second example, the center-to-center distances of the one input optical fiber 6a and the five output optical fibers 6b are the same. Therefore, this third example achieves the same effects as the second example. Note that in this third example, the cross-sectional shape of the hole may be changed from a regular pentagon in the same manner as described in the first example. Although not shown, the cross-sectional shape of the through-hole 7 may be circular (perfect circle).

[0098] Furthermore, although not shown, the cross-sectional shape of the through hole 7 may be square, and one input optical fiber 6a with a relatively small diameter and four output optical fibers 6b with relatively large diameters arranged on the outer periphery of the input optical fiber 6a may be inserted and fixed into the through hole 7. In this case, too, a total of five optical fibers 6a, 6b are densely housed in the through hole 7 in the same manner as in the second example above, and, as in the second example, the distances between the centers of the one input optical fiber 6a and the four output optical fibers 6b are equal. Also in this case, the cross-sectional shape of the hole may be changed based on a square, in the same manner as described in the first example above, and the cross-sectional shape of the through hole 7 may be circular (a perfect circle).

[0099] FIG. 29 is a front view of an optical component 2 including a capillary 5 according to a fourth example of the third embodiment of the present invention. As shown in the figure, the cross-sectional shape of one through-hole 7 provided in the center of the capillary 5 is a regular octagon. In the optical component 2, one input optical fiber 6a with a relatively large diameter and eight output optical fibers 6b with relatively small diameters arranged on the outer periphery of the input optical fiber 6a are inserted and fixed in the one through-hole 7. These nine optical fibers 6a, 6b are densely packed in the through-hole 7 in the same manner as in the second example. In this fourth example, as in the second example, the center-to-center distances of the one input optical fiber 6a and the eight output optical fibers 6b are the same. Therefore, this fourth example achieves the same effects as the second example. Note that in this fourth example, the cross-sectional shape of the hole may be changed from a regular octagon in the same manner as in the first example. Although not shown, the cross-sectional shape of the through-hole 7 may be circular (perfect circle).

[0100] Furthermore, although not shown, the cross-sectional shape of the through hole 7 may be a regular N-gon (where N is an integer of 7 or 9 or greater), and one input optical fiber 6a having a relatively large diameter and N output optical fibers 6b having relatively small diameters arranged on the outer periphery of the input optical fiber 6a may be inserted and fixed into the through hole 7. In this case, too, a total of N+1 optical fibers 6a, 6b are densely housed in the through hole 7 in the same manner as in the second example above, and the distances between the centers of the one input optical fiber 6a and the N output optical fibers 6b are equal, as in the second example above. Furthermore, in this case, too, the cross-sectional shape of the hole may be changed based on the regular N-gon in the same manner as described in the first example above, and the cross-sectional shape of the through hole 7 may be circular (a perfect circle).

[0101] Although the third embodiment of the present invention has been described above, this third embodiment is not limited to this, and various modifications are possible without departing from the spirit of the present invention.

[0102] For example, in the third embodiment, the through-hole 7 is provided at one location in the center of the capillary 5, but the through-holes 7 may be provided in parallel at a plurality of locations on the capillary 5.

[0103] The through hole 7 in the third embodiment may have a tapered portion that gradually widens toward the opening on the rear end face side or the front end face side of the capillary 5, similar to the single input or output through hole 5a (5b) in the first embodiment.

[0104] In the second, third and fourth examples of the third embodiment described above, one input optical fiber 6 a and multiple output optical fibers 6 b are inserted and fixed together in one through-hole 7, but two or more input optical fibers 6 a and an even larger number of output optical fibers 6 b may also be inserted and fixed together in one through-hole 7.

[0105] Although the embodiments of the present invention (first, second, and third embodiments) have been described above, the present invention is not limited to these embodiments and various modifications can be made without departing from the spirit and scope of the present invention. For example, in the embodiments of the present invention, the outer shape of the capillary 5 is circular (perfect circle) in cross section. However, the outer shape may have an orientation flat in cross section. Furthermore, the outer shape of the capillary 5 may be triangular (preferably equilateral triangle), rectangular (preferably square), or other polygonal (preferably regular polygon) in cross section. In this case, for example, when assembling optical components such as optical switches, positioning is facilitated and the positions of through-holes into which optical fibers are inserted are also easily fixed. That is, by placing the orientation flat portion or rectangular flat portion of the capillary 5 in a predetermined position, the positions of the input and output through-holes can be determined. This makes it easier to adjust the tilt (angle) of the mirror, thereby enabling further improvement in optical loss characteristics.

[0106] REFERENCE SIGNS LIST 1 Optical switch 2 Optical component 3 Lens 4 Mirror 5 Capillary for holding optical fiber (capillary) 5a Input through-hole 5b Output through-hole 5f Tapered portion 5g Opening 5h Connecting portion 5k Tapered portion 5m Tapered portion 5n Opening 5p Opening 5r Connecting portion 6a Input optical fiber 6b Output optical fiber 7 Through-hole L3 Center-to-center distance L4 Center-to-center distance X Central axis

Claims

1. An optical fiber holding capillary used in an optical switch including an optical fiber, a lens or prism, and a mirror, characterized in that each said optical fiber holding capillary has an input through-hole for inserting and fixing one or more input optical fibers, and an output through-hole arranged parallel to said input through-hole for inserting and fixing one or more output optical fibers.

2. The optical fiber holding capillary according to claim 1, characterized in that it is provided with one input through-hole for inserting and fixing one input optical fiber, and a plurality of output through-holes for respectively inserting and fixing a plurality of output optical fibers.

3. The capillary for holding an optical fiber according to claim 2, wherein the plurality of output through holes are arranged concentrically around the input through hole.

4. The capillary for holding an optical fiber according to claim 3, wherein the plurality of output through holes are arranged at equal angular intervals.

5. The capillary for holding an optical fiber according to any one of claims 1 to 4, wherein the cross section of the output through hole has a circular shape.

6. The capillary for holding an optical fiber according to any one of claims 1 to 4, wherein the cross section of the input through hole has a circular shape.

7. The optical fiber holding capillary according to claim 1, characterized in that it is provided with one input through-hole for inserting and fixing one input optical fiber, or one or more input through-holes for inserting and fixing a plurality of input optical fibers together, and one or more output through-holes for inserting and fixing a plurality of output optical fibers together.

8. The capillary for holding an optical fiber according to claim 7, wherein the cross-sectional area of ​​the output through-hole is larger than that of the input through-hole.

9. A capillary for holding an optical fiber as described in claim 8, characterized in that it has one input through hole for inserting and fixing one input optical fiber, the cross-sectional shape of the input through hole being circular, and the cross-sectional shape of the output through hole being rectangular.

10. A capillary for holding an optical fiber as described in any one of claims 1 to 4, characterized in that the input through hole and the output through hole have tapered portions that gradually widen toward one of the openings formed at both ends of each.

11. The capillary for holding an optical fiber according to claim 10, characterized in that it has a communication part that connects the input through hole and the output through hole at the end of each of the openings on the one side.

12. An optical component used in an optical switch including an optical fiber, a lens or prism, and a mirror, characterized in that an input through hole and an output through hole arranged parallel to the input through hole are provided in one optical fiber holding capillary that holds the optical fiber, one or more input optical fibers are inserted and fixed in the input through hole, and multiple output optical fibers are inserted and fixed in the output through hole.

13. An optical switch comprising an optical fiber, an optical fiber holding capillary, a lens or prism, and a mirror, wherein each of the optical fiber holding capillaries is provided with an input through hole and an output through hole arranged parallel to the input through hole, one or more input optical fibers are inserted and fixed into the input through hole, and multiple output optical fibers are inserted and fixed into the output through hole, and one of the input optical fibers and one of the output optical fibers are selected according to the inclination of the mirror, and the selected optical fibers are optically connected via the lens or prism.

14. A capillary for holding an optical fiber used in an optical switch including an optical fiber, a lens or prism, and a mirror, characterized in that each capillary for holding an optical fiber has one through-hole in at least one location for inserting and fixing a total of three or more input optical fibers and output optical fibers together.

15. A capillary for holding optical fibers as described in claim 14, characterized in that the one through hole is for inserting and fixing a total of three input optical fibers and three output optical fibers together, and the cross-sectional shape of the one through hole is such that the distances between the centers of all three optical fibers are equal and the three optical fibers are closely packed together.

16. The capillary for holding an optical fiber according to claim 15, wherein the cross section of the hole has an equilateral triangle shape.

17. A capillary for holding optical fibers as described in claim 14, characterized in that the one through hole is for inserting and fixing one input optical fiber and multiple output optical fibers arranged on the outer periphery of the one input fiber together, and the cross-sectional shape of the one through hole is such that the distances between the centers of the one input optical fiber and the multiple optical fibers are all equal and the one input optical fiber and the multiple optical fibers are housed in a dense state.

18. An optical component used in an optical switch comprising an optical fiber, an optical fiber holding capillary, a lens or prism, and a mirror, characterized in that one optical fiber holding capillary is provided with one through-hole at at least one location, and a total of three or more input optical fibers and output optical fibers are inserted and fixed together in one through-hole.

19. An optical switch comprising an optical fiber, an optical fiber holding capillary, a lens or prism, and a mirror, wherein one through-hole is provided in at least one location on one of the optical fiber holding capillaries, a total of three or more input optical fibers and output optical fibers are inserted and fixed into the one through-hole, one of the input optical fibers and one of the output optical fibers are selected according to the inclination of the mirror, and the selected optical fibers are optically connected via the lens or prism.

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