WO2003069387A1

WO2003069387A1 - Optical coupler for optical connecting, optical branching or optical collecting

Info

Publication number: WO2003069387A1
Application number: PCT/JP2003/001469
Authority: WO
Inventors: Shoichi Nakamura; Nagahisa Machida
Original assignee: Acp Japan Co., Ltd.; Machida Toolex Co., Ltd.
Priority date: 2002-02-13
Filing date: 2003-02-13
Publication date: 2003-08-21
Also published as: JP2003232954A; AU2003211944A1; JP3833122B2

Abstract

An optical branching/optical collecting-use coupler for branching a ray of light propagated through one optical fiber into a plurality of optical fibers, and collecting a plurality of rays of light transmitted through a plurality of optical fibers into one or a plurality of optical fibers. An optical branching/coupler comprising a hollow or transparent element-filled spherical element provided with a reflection member for totally reflecting light off the inner surface of the outer periphery of a spherical element, a plurality of openings provided in the surface of a spherical element and formed so that their center lines pass the center of a spherical element, and optical fiber connection means provided in the openings, wherein a plurality of the spherical elements are coupled via one of the openings, the optical axis center line of a multiple-mode optical fiber connected with the above optical fiber connection means passes the center of the spherical elements, and arbitrary one or a plurality of openings out of the above openings are used as light incident ports and the other one or a plurality of openings are used as light outgoing ports.

Description

Description Optical coupler for optical connection, optical branching or optical aggregation

The present invention relates to an optical coupler for connecting, branching, or converging light such as a laser beam guided by an optical fiber, and more particularly, to splitting one light beam into a plurality of light beams, or combining a plurality of light beams. Optical coupler for assembling into a single light beam. Background art

An optical communication system in which a modulated laser beam is propagated through an optical fiber has extremely excellent transmission characteristics such as low loss, wide band, and non-induction. Optical fibers have physical characteristics such as small diameter and light weight, and optical communication is capable of long distance and large capacity transmission. In recent years, the reduction in manufacturing costs of high-power semiconductor laser devices and low-loss optical fibers has been realized. Measurement fields such as pressure and pressure are being used as transmission media for these measurement signals, and their application fields have been expanding in recent years.

With the expansion of the field of use of such optical fibers, there is a need for a technique for coupling, branching, or collecting light beams propagated by the optical fibers in the middle or at the end of a transmission line. Optical fibers come in a wide variety of shapes, from diameters of about 0.05 mm to 0.3 mm to visibly thick, and the core of the optical fiber is usually of pure purity. Made of high quartz glass or plastic. Therefore, in order to combine the light beams propagated by the optical fibers, it is necessary to polish the cut surface of each of the two optical fibers and precisely align the cut surfaces.

In optical communication, in order to split a single light beam propagated by an optical fiber into a plurality of light beams, or to aggregate a plurality of light beams into one or more light beams, the light beams must travel outside the optical fiber. Optical branching method using optical means such as prisms, mirrors and lenses for refracting or reflecting light rays after refracting the light rays, and introducing the light beams branched or collected by these optical means back into the optical fiber. There is. In addition to the above-described optical branching method, a light beam is converted into electric energy by a light-receiving element such as a light-receiving diode, and the electric energy excites one or a plurality of semiconductor lasers again. There is an electrical branching method for introducing the light emitted in the above into an optical fiber.

As an optical branching method, there is a method using polarization (polarization), which is one of the properties of a light wave. Deflection is used for changing the course of a light beam in a free space optical switch or the like. Basic devices necessary for such polarization control include a wave plate, a birefringent plate, a polarization beam splitter, and a liquid crystal polarization control element.

Crystals such as quartz, calcite, and mica used in the above-described wave plate have a property called optical anisotropy in which the refractive index is not uniform in the direction of the electric field oscillation of light. More specifically, quartz and calcite belong to the group of uniaxial crystals, and mica belongs to the group of biaxial crystals.If light is incident in that direction, the refractive index can be seen in the same direction. There are two.

On the other hand, there is a difference in the propagation velocity between the orthogonally polarized components of light that is incident perpendicular to the optical axis (the ray that senses the isotropic refractive index is called the ordinary ray, and the other ray is called the extraordinary ray). Then, a phase difference is given between the two. If there is a phase difference between the ordinary ray and the extraordinary ray, when they are combined at the time of emission, the polarization plane changes with respect to the incident light. A wavelength plate that uses this principle is, for example, a 1Z4 wavelength plate that gives a phase of / 4 wavelength (90 °) and is used for mutual conversion between linearly polarized light and elliptically polarized light. The 1/2 wavelength gives a phase difference of 1/2 wavelength (180 °) and is used for rotating the plane of polarization of linearly polarized light. Next, the birefringent plate utilizes the property that when light is incident obliquely to the optical axis, the light propagates in different directions depending on the polarization. In other words, ordinary rays obey Snell's law of refraction, but extraordinary rays seem to behave strangely, contrary to Snell's refraction, under the influence of the refractive index gradient. This property is called birefringence. Calcite is a crystal with extremely large birefringence, and it is this property that makes things look double through calcite.

By inputting circularly polarized light, non-polarized light, or linearly polarized light whose polarization plane is inclined with respect to ordinary and extraordinary rays, a branching function by polarized light can be obtained. By rotating the plane of polarization of the input light, the output position (between two points) can be moved. Specifically, these devices are It can be realized with a parallel plate-shaped calcite cut out under conditions according to the ability.

A device that achieves the same function as a birefringent plate includes a modified beam splitter. The polarizing beam splitter has a pair of right-angle prisms bonded to each other with a slope, and a dielectric multilayer coating layer interposed therebetween. This principle utilizes the polarization dependence of the reflectance of light, which is not birefringent. The polarization dependence is enhanced by appropriately designing the thickness and refractive index of the multilayer film, and the introduced light is reflected by the dielectric multilayer and travels in a direction perpendicular to the incident light.

Next, regarding the liquid crystal polarization control element, liquid crystal is a general term for substances having a phase that does not belong to any of solids and liquids. There are properties that are almost complete according to the rules. Since the shape of liquid crystal molecules is long and thin, the refractive index that light perceives in the long and short directions of the molecules differs, and they generally exhibit strong optical anisotropy. The arrangement of the liquid crystal molecules is changed by applying an electric field from the outside. By using this property, it operates as a polarization control element.

Here, a configuration of a twisted nematic liquid crystal cell that is widely used as a display element such as a timepiece will be described as an example. The liquid crystal is sandwiched between two highly parallel glass plates. The thickness of the liquid crystal is usually about 10 / m, and a transparent electrode for applying an electric field to the liquid crystal and a special treatment layer for orienting the liquid crystal molecules in a specific direction are formed on the surfaces of both glass plates that are in contact with the liquid crystal. I have. The orientation directions of the upper and lower glass plates are perpendicular to each other so that the liquid crystal molecules draw a 90 ° helix parallel to the glass surface. When light having a polarization plane parallel or perpendicular to the alignment direction enters this cell, the polarization plane of the input light is rotated by 90 ° due to the optical anisotropy of the liquid crystal.

Now, when a voltage is applied to the liquid crystal through the transparent electrode, the liquid crystal molecules change their direction perpendicular to the glass surface. As a result, there is no optical anisotropy with respect to the input light, and the polarization plane of the input light passes through without being changed. In this way, the liquid crystal cell operates as a polarization control element that can dynamically rotate the plane of polarization by an external input.

Using these devices, a polarization device, a demultiplexer for demultiplexing light, a concentrator for collecting a plurality of lights, a splitter for splitting light, and the like are formed.

Japanese Patent Laid-Open No. 174963/1994 discloses, as optical branching methods, a first curved surface Sp 1 having an end face of a fiber 51 at a focal point O 1 and an end face of a fiber 52 at a focal point Oa 2 as shown in FIG. The light reflecting surface is arranged opposite to the second curved surface Sp2, and of the divergent light beams determined by the exit numerical aperture of the fiber 51, the light beam 55 on one side from the center line of the fiber 51 is incident on the input end face of the fiber 52, A plurality of unit optical elements 50 each having the first curved surface Sp l and the second curved surface Sp2 arranged so as to be incident at an incident angle corresponding to the optical fiber. Disclosed is an optical branching element sharing 51.

However, in the prior art relating to this optical branching, in order to split or converge light, a light beam in an optical fiber is radiated to an external space at once, and a prism or lens arranged on the optical path of the radiated light beam is used. By propagating the above-mentioned various polarization devices composed of semiconductors and the like, light is refracted in a desired direction, and a movable portion for moving the prism and the like in accordance with the refraction angle is required. Is extremely complicated. In addition, the alignment of the optical axis of the branched light beam with the deflection device is complicated, and it has been difficult to reduce the size and cost of the device. Furthermore, the light branching / aggregating element according to the prior art forms a first curved surface and a second curved surface such that a light beam refracted by radiating incident light onto a curved surface exits at an exit angle corresponding to the exit numerical aperture, and is reflected. It is necessary to precisely arrange the position of the exit from which the emitted light exits. Further, the position of the exit aperture is limited by the curved surface configuration. Therefore, the direction of the refraction of light is restricted, and a free exit port cannot be arranged.

On the other hand, the above-described electrical branching method requires a light receiving element, a semiconductor laser device, and their peripheral circuits and a power supply device at the branching point, thereby realizing a reduction in size and cost of the device. Was extremely difficult.

According to the present invention, optical fibers have been connected to each other, a light beam propagated by a single optical fiber has only been connected, and the light has been branched into a required number of optical fibers, or transmitted by a plurality of optical fibers. It is an object of the present invention to provide an optical coupler for optical coupling, optical branching, or optical aggregation that can be assembled into one or more optical fibers simply by connecting a plurality of light beams. Disclosure of the invention

For this reason, the present invention provides a sphere filled with a hollow or transparent body provided with a reflecting member for totally reflecting the light on the inner peripheral surface of the sphere, and provided on the surface of the sphere, A multi-mode light source having a plurality of openings formed so that the center line thereof passes through the center of the sphere, and optical fiber connection means provided in the openings; The optical axis center line of the fiber passes through the center of the sphere, one or more of the plurality of openings are light entrances, and the other one or more openings are light exits. The present invention provides an optical coupler for optical connection, branching, or aggregation.

The light beam in the multimode optical fiber has a certain optical axis area, not a beam of light, and the light beam is emitted from the end face of the optical fiber into the sphere at a radiation angle within a predetermined range. Since the light beam is reflected by the reflecting member provided on the inner surface of the sphere and reflected inside the sphere a plurality of times, the light beam guided into the sphere from one or more openings provided at arbitrary positions on the surface of the sphere. Will radiate.

The present invention further provides a plurality of spheres filled with a hollow or transparent body provided with a reflection member for totally reflecting light on the inner peripheral surface of the sphere, and provided on the surface of each of the spheres. It has a plurality of openings formed so that a center line passes through the center of the sphere, and optical fiber connection means provided in the opening, and the plurality of spheres have one of the openings. The optical axis center line of the multi-mode optical fiber connected to the optical fiber connecting means passes through the center of the connected sphere, and passes through any one of the plurality of openings in any one of the plurality of spheres. Another object of the present invention is to provide an optical coupler for optical connection, light branching, or light aggregation, wherein a plurality of light entrances are used and another one or a plurality of openings are used as light exits.

Thus, a large number of light entrances and light exits can be provided, and diversification of light entrance and light exit can be achieved.

Here, the plurality of spheres are directly connected to each other by being in close contact with each other at one of the openings, or the spheres are connected via optical fibers connected to the respective optical fiber connecting means. It is connected in a shape.

The present invention further comprises a reflecting member for totally reflecting light on the inner peripheral surface of the outer periphery of the sphere, and the inside thereof has a refractive index gradually toward the outer periphery centered on a position different from the center of the sphere. A sphere filled with the changed transparent body, and a plurality of openings provided on the surface of the sphere and having a center line passing through the center of the sphere, Optical fiber connection means provided in the opening, wherein one or more of the plurality of openings are light entrances and the other one or more openings are light exits. The present invention provides an optical coupler for optical connection, optical branching, or optical aggregation.

Thus, even when the optical fiber connected to the optical coupler is of a single mode type, the refractive index inside the sphere gradually changes toward the outer periphery at a position different from the center of the sphere. Due to the effect of the changed transparent body, the beam light from the optical fiber is bent in the sphere, and the light beam is reflected by the reflecting member attached to the inner surface of the sphere, and reflected several times in the sphere. Light rays guided into the sphere are emitted from one or a plurality of openings provided at arbitrary positions on the sphere surface.

The present invention further comprises a reflecting member for totally reflecting light on the inner peripheral surface of the outer periphery of the sphere, and the inside thereof has a refractive index gradually toward the outer periphery centered on a position different from the center of the sphere. Spheres filled with the changed transparent body, a plurality of openings provided on the surface of each of the spheres, the center lines of which are formed to pass through the centers of the spheres, and the spheres provided at the openings. Optical fiber connection means, wherein the plurality of spheres are coupled through one of the openings, and any one or more of any one of the plurality of openings in the plurality of spheres is provided. An optical coupler for optical connection, optical branching, or optical assembly, wherein the optical coupler is used as a light entrance port and one or more other openings are used as light exit ports. Thus, many light entrances and light exits can be provided, and diversification of light entrance and light exit can be achieved.

Here, the refractive index of the transparent body is set so as to gradually increase from the center to the outer periphery. Further, the refractive index of the transparent body is set so as to gradually decrease from the center to the outer periphery.

Then, the plurality of spheres are directly connected to each other by being closely attached to each other at one of the openings. Further, the plurality of spheres are connected in a tuft shape via optical fibers connected to the respective optical fiber connecting means.

The present invention also provides a sphere filled with a hollow or transparent body provided with a reflecting member for totally reflecting light on the outer peripheral inner surface of the sphere, and a sphere provided on the surface of the sphere, the center line of which is provided on the sphere. A plurality of openings formed to pass through the center; A plurality of apertures, comprising: a magnetic generation unit provided at a position facing the circumference and arranged to refract incident light; and an optical fiber connection unit provided at the opening. Provided is an optical coupler for optical connection, light branching, or light aggregation, in which any one or more of the units is a light entrance and the other one or more openings are a light exit. Furthermore, the present invention provides a sphere filled with a hollow or transparent body provided with a reflecting member for totally reflecting light on the inner peripheral surface of the sphere, and a sphere provided on the surface of the sphere, the center line of which is provided by the sphere. A plurality of openings formed so as to pass through the center of the sphere, a magnet generating means provided at a position facing the outer periphery of the sphere, and arranged to refract incident light, and provided at the opening. Optical fiber connection means, wherein the plurality of spheres are coupled through one of the openings, and any one or any of a plurality of openings in any one of the plurality of spheres is provided. An object of the present invention is to provide an optical coupler for optical connection, light branching, or light condensing, wherein a plurality of light entrances are used and another one or a plurality of openings are light exits.

Then, the plurality of spheres are directly connected to each other at one of the openings by being closely attached to each other, or are in a tuft form via optical fibers connected to the respective optical fiber connecting means. It is characterized by being connected to.

The material of the transparent body is formed of a transparent material such as an inorganic material oxide glass, high-purity glass, and plastic.

Further, the entrance and the exit are formed by removing a part of the reflection member in a circular shape. Here, the reflection member is attached to the surface of the transparent sphere by sputter coating or vacuum deposition. The reflection member is formed of a single-layer metal or a light-impermeable material in which two or three different metals are stacked and deposited. In the optical coupler according to the present invention, one opening provided on the surface of the sphere is a light entrance, and another plurality of openings provided in a strip shape on the surface of the sphere is a light exit. In addition, one opening provided on the surface of the sphere is a light emitting port, and other plural openings provided in a strip shape on the surface of the sphere are light receiving ports.

Further, in the optical coupler according to the present invention, two or three spheres are connected to each other in a state where the openings are in close contact with each other. One opening of the one connected sphere is a light entrance, and all other openings are light exits. It is characterized by the following. Furthermore, one opening of the one connected sphere is a light exit, and all other openings are light entrances.

As described above, the optical coupler for optical connection, optical branching, or light aggregation of the present invention has a simple configuration in which a light beam is reflected a plurality of times in a sphere and emitted from an emission port, and optical connection, optical branching, and The optical assembly can be realized by one optical coupler, and it is possible to freely set which of the plurality of optical fiber connection means provided at the plurality of openings on the surface of the sphere to be the light entrance or exit. . BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a partially cut-away side view of an optical coupler according to the present invention.

FIG. 2 shows a form in which incident light from an optical fiber is uniformly dispersed and reflected in the optical coupler.

FIG. 3 is a cross-sectional view illustrating a change in the refractive index of a transparent body filled in a sphere.

FIG. 4 is a cross-sectional view in which magnetic generating means is provided along the outer periphery of the sphere.

FIG. 5 shows a sectional view of a connecting means for connecting a sphere and an optical fiber.

FIG. 6 shows a cross-sectional view in which two exit ports are provided in the optical coupler.

FIG. 7 is a cross-sectional view in which the optical coupler is provided with two entrances and one exit.

FIG. 8 shows a diagram in which two optical couplers are connected and coupled.

FIG. 9 shows a diagram in which three optical couplers are connected and coupled.

FIG. 10 is a schematic diagram in which a plurality of small optical couplers are connected in a tuft around one optical coupler.

FIG. 11 is a cross-sectional view in which a predetermined number of emission ports are formed all around the optical coupler. FIG. 12 shows a conceptual diagram of a 2X2 switch using an optical coupler.

FIG. 13 shows the basic configuration of a distribution-selective switch using an optical coupler.

FIG. 14 shows an example of a basic configuration of a wavelength routing type switch using an optical coupler.

FIG. 15 shows a configuration diagram of an optical branching / gathering element according to the prior art. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of an optical coupler for optical branching or optical aggregation according to the present invention will be described in detail with reference to the drawings.

Light propagation using an optical fiber is a multi-mode in which light propagates in multiple-path propagation modes due to differences in the refractive index distribution shape, number of propagation modes, materials, manufacturing methods, and structures. There is a single mode light propagation through which the light beam propagates. The optical fiber includes a multi-mode optical fiber and a single-mode optical fiber. In the first mode of the embodiment of the present invention, the light beam to which the optical coupler is adapted is a multimode light beam, and the optical fiber uses a multimode type.

The optical coupler according to the first embodiment of the present invention optically couples a light beam guided by a multimode optical fiber, and the light beam in the multimode optical fiber is not a beam of light but a straight line. Since the light beam has a certain optical axis area and is emitted into the sphere at an emission angle within a predetermined range from the end face of the optical fiber, the light beam is reflected by the reflecting member attached to the inner surface of the sphere. However, since the light is reflected a plurality of times in the sphere, light rays guided into the sphere are radiated from one or a plurality of openings provided at arbitrary positions on the surface of the sphere.

The optical coupler according to the second embodiment of the present invention optically couples a light beam guided by a single-mode optical fiber, and gradually moves toward the outer periphery around a position different from the center of the sphere. Due to the action of the transparent body whose refractive index is changed, the light beam from the optical fiber is bent in the sphere, and the light beam is reflected by a reflecting member provided on the inner surface of the sphere, and the light in the sphere becomes plural. Since the light is reflected twice, light rays guided into the sphere are radiated from one or a plurality of openings provided at arbitrary positions on the surface of the sphere. FIG. 1 is a partially cut-away side view showing an embodiment of the optical coupler 5 of the present invention. Since the optical coupler 5 normally branches and aggregates the light propagating in the optical fiber, it is used by being welded to the end of the optical fiber. The structure is such that a sphere 2 (for example, a glass sphere or a plastic sphere) filled with a hollow or transparent body is connected to an optical fiber 1 that guides light (laser light), A reflecting member 3 for reflecting light (for example, sputter coating or vacuum evaporation), one or more openings 4, and an optical fiber connecting means 9; Constitutes an optical coupler 5 for optical coupling, optical branching or optical assembly.

FIG. 2 shows a state in which the incident light 10 from the optical fiber 1 is uniformly dispersed and reflected in the optical coupler 5.

Light from a laser light source or a general light source placed near the base end (left side in the figure) of the optical fiber 1 enters the optical coupler 5 from the tip of the optical fiber 1 connected to the sphere 2, and the reflecting member 3 The light is uniformly reflected on the inner surface of the sphere 2, and is reflected innumerably many times in the sphere 2 and flutters. Irradiation direction).

The light ray introduced into the sphere 2 from the light entrance is reflected from the reflection member 3 attached to the sphere 2 a plurality of times and then emitted from the light exit 4 with a repeated number of reflections. The transmission band of the emitted light beam is narrower than the transmission band of the incident light beam, but the luminous intensity of the reflected light is attenuated each time the reflection is repeated within the sphere 2, so the electrical signal of the attenuated light By the processing, the optical coupler according to the present invention can sufficiently cope with medium-range and medium-band optical transmission.

The light output port 4 can be formed at an arbitrary position so as to realize a required refraction and output direction with respect to the optical axis center line L of the incident light depending on the application. Further, the number of the light emission ports 4 is not limited to one, and a required number can be provided. The shape of the light emission port 4 is circular in a plan view in the embodiment, but may be various shapes (for example, a band shape, an elliptical shape). Etc.) can be formed.

Also, due to the reversibility of light, light can also pass through the reverse path. That is, a plurality of incident lights 10 can be aggregated as one outgoing light.

Note that, in the example shown in FIG. 1, the force shown as that the center line L of the optical axis of the optical fiber 1 substantially coincides with the center line of the optical coupler 5 is not limited to this. The center line L and the center line of the sphere 2 can be shifted and connected.

The optical coupler 5a used when branching and collecting the single-mode light 10b of the second form is gradually refracted toward the outer periphery around the center 46 at a position different from the center 45 of the sphere 2 inside. It is composed of a sphere 2 filled with a transparent body of varying rate. Note that, in FIG. 3, the line 47 indicates the equal refractive index of the transparent body having the changed refractive index.

FIG. 3 (a) shows a state in which the refractive index of the transparent body is set to gradually increase from the center to the outer periphery. The intervals between the lines 47 indicating the equal refractive index become closer as they approach the vicinity of the center 46 at different positions. The light 10b travels to the upper X point of the sphere 2 in the figure while changing the refractive index and refracting by the transparent body in the sphere 2 that transmits. FIG. 3 (b) shows a state in which the refractive index of the transparent body is set to gradually decrease from the center to the outer periphery. The interval between the lines 47 indicating the equal refractive index becomes narrower as approaching the vicinity of the center 46 at different positions. The light 10b travels to the lower Y point of the sphere 2 in the figure while changing the refractive index and being refracted by the transparent body in the sphere 2 that transmits.

The single-mode incident light 10b from the optical fiber 1 reaches the reflecting member 3 while changing the refractive index and being refracted by the transparent body in the transmitting sphere 2. The light 10 b is emitted from the light exit 4 by repeating the same reflection when the multi-mode light beam is irregularly reflected in the sphere 2.

A plurality of openings are provided on the surface of the sphere 2, and the openings are formed with one or a plurality of optical fiber connection means and a light emission port 4. The connection between the opening provided in the spherical body 2 and the optical fiber connecting means and the optical fiber is made by optical fiber connecting means or welding.

In this case as well, similarly to the optical coupler for a multimode optical fiber described above, the incident light 10b introduced into the sphere 2 from the light entrance is reflected by the reflecting member 3 attached to the sphere 2 several times. After being reflected, the light is emitted from the light exit 4 with the number of reflections repeated, so that the transmission band of the exit light emitted from the light exit 4 is narrower than the transmission band of the incident light, but within the sphere 2. Since the luminous intensity of the reflected light is attenuated each time the reflection is repeated, the optical coupler according to the present invention can sufficiently cope with medium-range and mid-band optical transmission by electrical signal processing of the attenuated light. It is.

FIG. 4 is a cross-sectional view in which magnetic generating means is provided at a position facing the outer periphery of the sphere 2. In the third mode, the inside of the sphere 2 of the optical coupler used when branching and collecting the single mode light 10b is formed of a hollow or transparent body. The sphere 2 is provided with a light entrance 7 and exits 4a and 4b. In order to refract the incident light in the sphere 2, The magnetism generating means 29 is provided along the outer peripheral surface of the spherical body 2 with the N pole side 29a and the S pole side 29b facing each other. A power supply cable 100 from a power supply is connected to the magnetism generating means 29a and 29b in order to supply a current to a coil wound on a magnetic body.

The single-mode light 10b incident on the sphere 2 from the light entrance 7 is refracted in the traveling direction by the magnetic fields from the magnetism generating means 29a and 29b, and travels to the reflecting member 3 attached to the sphere 2. After being reflected a plurality of times, the light is emitted from the light emission ports 4a and 4b with the number of reflections being repeated. Further, the refractive index of light can be changed by changing the strength of the magnetic field. In this embodiment, a permanent magnet using an electromagnet may be used as the magnetism generating means. Furthermore, if a superconducting magnetic material is used, it can be used as a high-performance magnetic generating means.

FIG. 5 shows a sectional view of 40 examples of the optical fiber connecting means. The optical fiber connecting means 40 is composed of a member 43 for aligning and holding the optical fiber 1, a mechanism for fixing the optical fiber, and a plug 41 composed of a fastening mechanism. It is composed of an adapter 42 for causing the connection. The core diameter of the optical fiber 1 used is, for example, 50 / m to 200 / m for a multimode fiber, and 10 μηι for a single mode fiber, considering a glass-based optical fiber. is there. Therefore, a slight imperfect matching accuracy causes an increase in connection loss. Optical fiber connection methods using connection means can be classified into two types: end face-to-face connection methods and connection methods via lenses. In the lens system, stable characteristics can be obtained because the parallel beam diameter of the connection part can be larger than that of the fiber core system.On the other hand, since the number of parts is large and the connection loss is large, most of the lens systems adopt the end face butt method. I have. In the alignment structure, the sleeve alignment structure and the circle that applies a uniform force to the ferrule or fiber in the radial direction A method of aligning the center axis with a cylindrical sleeve), a groove alignment structure, and a guide pin alignment structure. Usually, in the case of single-core optical connection means, there are many alignment structures using a cylindrical sleeve. The fastening structure includes various simple operation type fastening structures such as a bayonet fastening structure in addition to a general screw-type fastening structure.

One plug 41 a of the connection means 40 is fixed to the optical fiber connection means 9 and the opening 4 of the sphere 2. The optical fiber 1 is inserted into the ferrule 43, and the ferrule 43 and the adapter 42 are screwed into the plug 41a. Next, the plug 41b is turned and screwed with the fastening screw 44 provided on the plug 41b and the adapter 42 to be fixed to the sphere 2. Thus, the optical fiber 1 is accurately connected to the optical fiber connecting means 9 and the opening 4. Further, the optical fiber 1 can be removed from the optical coupler 5.

Further, the connection between the other sphere 2 and the optical fiber can be performed by welding without using the connecting means 40 as described above. In this case, the tip of the optical fiber has a convex shape, and the welding position of the spherical body 2 has a concave shape. Alternatively, the tip of the fiber is made concave, and the welding portion of the sphere 2 is made convex accordingly. Such a complementary uneven shape is necessary to make the welding accurate and strong.

In the present embodiment, the connection method between the sphere 2 and the optical fiber 1 is not limited to the connection example shown in the connection example by the plug and the connection example by welding, and the connection method is not limited to the connection described in this embodiment example. It may be to do.

On the surface of the sphere 2, the reflection member 3 is omitted, and the optical fiber connection means and the emission port 4 are formed. In the example shown in FIG. 1, the light exit 4 is positioned so as to coincide with the direction of the refraction angle of 90 ° with respect to the center line (line L) of the straight optical axis of the laser beam. It is formed by removing the reflection member 3.

The optical fiber 1 used in this device is very thin, such as a glass-based optical fiber, and its diameter is as small as 50 μιη to 200 μΐη for a multimode fiber and 10 m for a single mode fiber. Glass fibers or plastic fibers of various shapes can be used.

The sphere 2 needs to be optically a true sphere, and is made of an inorganic material such as an oxide glass, particularly a high-purity glass. Can be manufactured. The metal material used for the reflecting member 3 is not particularly limited, and any material that is suitable for vacuum deposition or further CVD and is light-impermeable can be used.

Further, the reflecting member 3 can be formed by depositing different kinds of metals, not only a single layer of metal, in two layers or three phases.

For the purpose of reinforcing the sphere 2, the reflecting member 3 is preferably as thick as possible. Therefore, it is preferable to form a relatively thick reinforcing film of metal by spattering and further by a plating method.

Here, an embodiment of the optical coupler 5 in which light propagated in the optical fiber 1 branches or converges will be described. The optical couplers 5 of the optical coupler 5 according to the present invention are configured such that one or more optical couplers 5 can be used to obtain light obtained by refracting incident light at an angle in a predetermined direction from the center of the optical axis. It is configured.

The light branch takes the incident light 10 into the optical coupler 5, reflects the light in the sphere countless times, and emits the light through one or more light exit ports 4 provided in the optical coupler 5.

FIG. 6 shows an example in which two light emission ports 4 are provided in the optical coupler 5. An optical fiber 1 for transmitting light is connected to the light exit ports 4a and 4b in the same shape as the light incident side. The light enters the optical coupler 5 from the tip of the fiber 1, is uniformly dispersed and reflected on the inner surface of the reflecting member 3, and is reflected innumerably many times in a sphere so as to fly, but the two light exit ports 4 a, An exit is found at 4b, and emitted light A and B are emitted linearly from the exit. That is, the incident light 10 is branched into the outgoing light A and the outgoing light B, and is branched and output from the two light output ports 4a and 4b.

FIG. 7 shows an example in which the optical coupler 5 is provided with two entrances 7a and 7b, and one exit 8 is provided. This indicates that light can pass through the reverse path due to the reversibility of light in the operation opposite to the branching of light shown in FIG. The incident lights 10a and 10b enter the optical coupler 5 from the two entrances 7a and 7b, are uniformly dispersed and reflected on the inner surface of the reflecting member 3, are reflected innumerably many times in the sphere, and fly out, and exit. An exit is found at 8, and the light exits from the exit and exits from the exit 8 linearly. That is, the incident lights 10a and 10b from the two entrances 7a and 7b are gathered at one exit 8 and emitted.

Next, an example in which two optical couplers 15 are connected to split light will be described. FIG. 8 shows a diagram in which two optical couplers 15 are connected and fixed to perform optical branching and aggregation. The connecting portion of the optical coupler 15 is tightly fixed to a connecting port 18 which is one of the openings so as to prevent light leakage. The optical coupler 15 has a predetermined number of emission ports 17 formed therein. The incident light 10 from the optical fiber 1 enters the optical coupler 5 and is uniformly dispersed and reflected on the inner surface of the reflecting member 3. An exit is found at 18, and the light exits straight from there.

By connecting two optical couplers 15, it becomes possible to split the incident light 10 from the optical fiber 1 to a plurality of light output ports 17 provided in the optical coupler 5 and emit the light.

FIG. 9 is a diagram showing a state where three optical couplers 16 are connected. In the case of this embodiment, the optical couplers 16 are connected to each other in the same manner as in FIG. 8, but it is possible to split the incident light from the optical fiber 1 to a larger number of emission ports 17. Each optical coupler 16 is formed with a predetermined number of emission ports 17 at a predetermined angle from the center of the sphere 2. The optical fiber 1 is connected to each output port 17. The incident light 10 from the optical fiber 1 enters the optical coupler 16, is uniformly dispersed and reflected by the inner surface of the reflecting member 3, exits at the exit 17 and the coupling 18, and exits linearly therefrom.

By connecting three optical couplers 16, it becomes possible to split the incident light 10 from the optical fiber 1 to a plurality of output ports 17 provided in the optical coupler 16 and emit the light. Since the light emission port can be freely set at the distance of the incident rocker and at a wide angle position, the degree of freedom in equipment design is increased.

FIG. 10 shows a mode in which a plurality of small optical couplers 21 are connected in a tuft-like manner around one optical coupler 20 via an optical fiber. In this embodiment, the light incident from the entrance 22 of the optical coupler 20 enters the optical coupler 20, is uniformly and diffusely reflected on the inner surface of the reflection member 3, finds an exit at the exit 23, and from there. Emitted as output light. The light enters a plurality of small optical couplers 21 connected to the exit 23 via the optical fiber 1.

The incident light is again uniformly dispersed and reflected in the small optical couplers 21 and is output toward the optical fibers connected to the output ports provided in the respective optical couplers 21.

The optical coupler 21 may be directly connected to the optical coupler 20 without passing through the optical fiber 1, as shown in FIGS. 8 and 9. According to this connection, the loss of light attenuation is reduced, and more light branching is possible. FIG. 11 shows an example in which a predetermined number of light emission ports 26 are formed all around the optical coupler 25 provided at the tip of the optical fiber 1. The optical fiber 1 is connected to the light exit port 26. In this embodiment, the incident light 10 is refracted by 90 ° along the entire circumference of the optical coupler 25 and branched into a plurality of optical fibers. According to this embodiment, a plurality of optical branches can be performed in a limited space.

Here, an application example and an application example of the optical coupler 5 of the present invention in the optical communication field will be described.

Light has various characteristics compared to electricity. By taking advantage of the broadband, high-speed, and crosstalk-free interference characteristics of light, a large-capacity system that cannot be achieved with electronic technology can be realized. The features of optical switching include the following.

1. Since light has a wide band, it can switch high-bandwidth signals (hundreds of megahertz) that are electrically difficult to switch. Light has a vast bandwidth of 200 terahertz, and is characterized by being unaffected by external noise. This property can be used not only for optical propagation but also for optical switching.

2. Since light has a high speed, switching at a higher speed than an electrical switch is possible. With electronic switches, the upper limit of operating speed is determined by the carrier moving speed and the RC time constant of the circuit. In the case of light, there is no such problem, so higher-speed switching is possible in principle. In fact, high-speed operation with a switching time of about several picoseconds has been experimentally confirmed.

3. As a more aggressive use of the broadband nature of light, it is possible to divide the entire band into multiple frequency bands and switch independent signals carried by each. In principle, it is possible to use electricity, but in the case of light, frequency-division multiplexing is important because of the large merit of dividing the bandwidth due to its wide bandwidth and the required small circuit size due to the high carrier frequency. Propagation and switching are promising.

4. Light is not affected by external electromagnetic fields, so it does not interfere with light beams. Therefore, by using a high-density array device and miniaturizing the wiring system, three-dimensional high-density mounting is possible.

5. Optical switches generally perform switching by changing the physical characteristics (such as refractive index) of the medium, and therefore consume less energy than electronic switches, which consume less energy. A switch with low power can be realized.

As a basic switch element, the simplest switch is an on-off switch. When controlling flow, it is sometimes called a gate (on_off). There is only one input and one output, and there are only two switch states, on and off, so we can use lbit to represent that state. This type of switch is called a "binary switch". Various types of switches can be constructed by combining gate switches.

Next is a cross-nova switch. This is also a binary switch with two states, but differs from a point-gate switch with two inputs and two outputs. It has two states: two inputs and outputs connected in parallel (bar shape), and two inputs and outputs connected in a crossed state. Therefore, the two inputs are always connected to one of the two outputs, and there is no state in which the two inputs are connected to one output at the same time or not connected to any output. The most typical switch that can be combined with a crossbar switch is a banyan switch.

The third is a multi-valued switch, which selectively connects one input to one of two or more outputs, or connects one of two or more inputs to one. The switch connected to one output is called a multi-value switch. A typical switch of a multivalued switch is a rotary switch.

In a communication system, if one-to-one communication is targeted first, the simplest method of communication is to directly connect two parties to communicate. If there are N people, the number of combinations to select any two of them, that is, if N (N-1) / 2 lines are drawn, it will be possible to perform communication in combinations like degrees. However, in such a method, as N increases, the number of connections becomes enormous (on the order of N square), and it is physically impossible to achieve this. Therefore, if a switch is placed in the middle of the track connecting the people who want to communicate and it is connected according to the request, any N people can communicate with N connections. Switching the connection according to the request in this way is called “switching”. The primary function of switching is such a "reconnection", but at the same time, by allocating resources of the communication network as needed, it is possible to eliminate waste and provide communication at low cost. It also has an important role. In an actual network, switches have a hierarchical structure, and a connection connecting the switches is called a subscriber propagation path. The size of the exchange can be increased by layering The size of the network can be reduced to a reasonable size, and a total economic network can be realized.

Further, optical switching systems are classified into three systems: “space division” (SD), “time division multiplex” (TD), and “frequency division multiplex” (FD). On the other hand, the “broadband characteristics” that are the greatest features of optical technology include “broadband characteristics of a modulatable signal band” and “broadband characteristics of spatial resolution”. The term "broadband", which is used in conventional optical fiber communications and is most familiar, mainly refers to the first broadband, that is, the broadband in the time domain.

Optical switches are required for diversification, high reliability and economical use of optical fiber communication systems. Since the purpose of the optical switch is to switch the optical path, it is necessary that the insertion loss at the time of ON is low and the crosstalk attenuation at the time of OFF is large. Switching power, switching time, and switching delay time are also important evaluation items. Switches can be classified into mechanical type with moving parts and electronic type without moving parts. The mechanical optical switch has a low switch speed of millimeters, and is not suitable for mass production because it must be manufactured by combining a large number of optical components. However, although the response speed is slow, it has excellent optical characteristics and is already used at present. On the other hand, the electronic optical switch has features such as high-speed operation and high reliability because it has no moving parts.

In a mechanical optical switch, the optical path is switched by moving an optical fiber, a prism, a reflector, a lens, and the like, and a manual solenoid, a bimorph, a step motor, or the like is used as a driving means. The connection loss is around ldB, and the crosstalk attenuation is as high as 50dB. In principle, these optical switches do not matter whether the optical fiber connected to the outside is multi-mode or single-mode.However, for single mode, low loss and reproducibility of connection are required. High precision is required for parts processing and assembly.

The electronic optical switch can apply the optical effect and the acousto-optic effect similarly to the optical modulator and the optical deflector.

Various types of electronic optical switches are provided, such as a switch using a quartz glass waveguide, a switch using a semiconductor, a switch using a liquid crystal, and a switch using a liquid crystal.

The latest semiconductor optical switch changes the refractive index of a semiconductor by current or voltage, and causes a total reflection based on the refractive index difference to switch the light path. This is equivalent to controlling the reflection of light by moving a mirror, using the physical properties of semiconductors. It is realized by a fine circuit. Advances over the past include the elimination of moving parts, very fast operation, and the use of smaller switches. When high-speed switching becomes possible, signals can be time-multiplexed and switched independently, as in the current electronic exchange. Furthermore, when used as a semiconductor amplifier gate (SOAG), it becomes an optical gate element in which the amount of light can be controlled by the injected current. This semiconductor amplifier gate is capable of high-speed switching, has an amplification gain, and has a high on-Z-off ratio.

In a gate switch using liquid crystal, the polarization plane of light is controlled by liquid crystal to block light from passing through. Alternatively, high-frequency division multiplexing, which multiplexes light of different lengths and switches for each wavelength, has also become experimentally possible.

Despite being a fluid, liquid crystals have the property that molecules are almost aligned according to a certain rule, similar to solids. Since the shape of liquid crystal molecules is long and thin, the refractive index that light perceives in the long and short directions of the molecules is different, and the liquid crystal molecules generally show strong optical anisotropy. The arrangement of liquid crystal molecules changes when an electric field is applied from the outside. Control of transmitting or reflecting light in a specific direction can be performed by the applied voltage. An optical switching device can be constructed by utilizing this property. -In addition to an optical switch that uses a change in refractive index, an optical switch can be configured by using an optical gate element that can control light transmittance.

In a general gate switch, a 1X2 switch is composed of one optical branching circuit, two optical gates, and one optical merging circuit.

The 2X2 switch is composed of two optical branch circuits, four optical gates, and two optical convergence circuits. The optical gate operates as a shutter that turns light on and off, and performs light switching. This configuration is characterized in that branch connection is possible.

As the optical gate, various gates such as a gate using a silica glass waveguide, a gate using a semiconductor, a liquid crystal gate, and the like can be applied.

Here, an example of a 2 × 2 switch using the optical coupler of the present invention to configure the above-described gate switch will be described.

As shown in FIG. 12, the 2X2 switch using the optical coupler 30 is composed of four optical couplers 5a, 5b, 5c, 5d and four optical gate elements 30a, 30b, 30c, 30d. Reply Huay The input light A propagated from the bar is branched by the light totally reflected in the optical coupler 5a being emitted from the two emission ports, and reaches the optical gate elements 30a and 30b. At that time, a control device (not shown) controls to open the gate 30b through which light passes and close the other gate 30a. The light that has passed through the open gate 30b is collected as output light in the optical coupler 5d and output as output light Y. After the light is branched in this way, the light is guided to a desired optical path by the gate controlled on and off. That is, the function of the optical switch that performs the ON / OFF operation according to the predetermined control is performed.

All optical gates can be controlled on / off by the applied voltage by the control device, and there are no components to operate. Therefore, high-speed and stable switching is performed. The optical branching and aggregation are also simple structures in which the optical coupler 30 is provided.

Furthermore, by increasing the number of gates of the above-mentioned switches and arranging them appropriately, the number of inputs / outputs such as 4X4 and 8X8 can be increased to form a matrix switch.

Further, an application example of the optical coupler / splitter 5 to wavelength division multiplexing type optical switching will be described. In the NxN matrix switch in the space division type optical switching described above, when the size of the switch is increased, the number of 2X2 switches, which are unit switches, increases in proportion to the square of N, and it is difficult to increase the scale. Furthermore, it is not so easy to realize a switch with good characteristics as an NxN switch by accumulating the loss, the talk, etc. in each unit switch.

On the other hand, the carrier frequency of light is about 193 THz at a wavelength of 1.55 / m. This is the effective bandwidth of the sidebands by modulation has shown that a 1 93TH _Z, means that can be carried in light output As a result, information about lOOTbitZs from one laser Te, ru. By making full use of the broadband characteristics of light as described above, the problems arising in space division optical switching can be cleared. That is, in NxN switching, if N types of wavelengths are used and their multiplexing / demultiplexing techniques are used, it is possible to use the wavelengths that do not cause internal collisions and use the wavelengths as routing information.

Wavelength division multiplexing multiplexes a plurality of spatially separated incoming calls into a wavelength division highway. Alternatively, the switching is the reverse operation. Here, an example in which the optical coupler 5 is applied to two typical methods will be described.

a) Wavelength multiplexing optical switching based on distribution-selective switching network It is.

(4) Distribution-selective switching is an architecture that implements the function of space-division switching using wavelength division multiplexing technology. FIG. 13 shows the basic configuration of a distribution selection switch. The input electric signal is converted into an optical signal at each input port (110) by using a semiconductor laser (fixed wavelength laser) 35 for each input (a fixed wavelength laser). light signals from) via the optical fiber 1 is propagated to the optical coupler 5. propagated light is set by the optical coupler 5, with the optical signal of ^ _ _N is wavelength multiplexed The light is sent to each output port (1 to N) via the optical fiber 1. Each output port is provided with a variable wavelength filter 55. The variable wavelength filter 36 transmits or reflects light in a predetermined wavelength band. It has a function to select light in a predetermined wavelength band by reflecting or transmitting light in other wavelength bands, such as transmitting only light in the blue wavelength band (about 47 Onm), The variable wavelength filter 36 reflects the routing information. According to the above, the desired optical signal (wavelength) is selected.The above operation enables the switching of 。.The architecture of this switch uses fixed wavelength transmitter and variable length receiver, so fixed transmission and variable reception It is also called (FT-TR) type network.

b) Next, an example of application to wavelength multiplexing type optical switching based on a wavelength routing type switching network will be described.

As with the distribution-selective switch, there is a wavelength-routing switch as an architecture that realizes the function of NxN space division optical switching using wavelength multiplexing technology. FIG. 14 shows a schematic diagram of the basic configuration of a wavelength routing switch. An optical signal from each port (fi to f _N ) is propagated to the optical coupler 5 via the optical fiber 1.

Propagated light is set by the optical coupler 5, example is sent in a state in which optical signals _ _N is wavelength-multiplexed to each reception port (through f _N). In this architecture, a unique wavelength filter (fixed wavelength filter) 38 is installed at each receiving port, and NxN switching is performed by transmitting an optical signal at the wavelength of the target output port by the tunable laser 37 at each transmitting port. Is realized. Since this switch architecture uses a variable wavelength transmitter and a fixed wavelength receiver, it is also called a TT-FR (variable transmission, fixed reception) type network. As described in detail above, the optical coupler of the present invention includes a sphere filled with a hollow or transparent body provided with a reflecting member for totally reflecting light on the outer peripheral inner surface of the sphere, and provided on the surface of the sphere. A plurality of openings formed so that the center line passes through the center of the sphere, and optical fiber connecting means provided in the opening, and an optical fiber connected to the optical fiber connecting means. An optical axis center line passes through the center of the sphere, and one or more of the plurality of openings are light entrances, and the other one or a plurality of openings are light exits.

Accordingly, the optical coupler for optical connection, optical branching, or optical aggregation has a simple configuration in which light rays are reflected multiple times in the sphere and emitted from the emission port, and optical coupling, optical branching, and optical aggregation are performed. A single optical coupler can be realized, and any of a plurality of optical fiber connection means provided at a plurality of openings on the surface of the sphere can be used as a light input port or a light output port, and a number of light input ports and light output ports can be provided In addition, optical fibers can be coupled to each other, split into the required number of optical fibers simply by connecting the light beams propagated by one optical fiber, or transmitted by multiple optical fibers. An extremely versatile optical coupler for optical coupling, optical branching, or optical aggregation that can be assembled into one or more optical fibers simply by connecting multiple light beams It is. Industrial applications

The present invention relates to an optical coupler for connecting, branching, or collecting light such as a laser beam guided by an optical fiber, and has industrial application in the field of optical communication.

Claims

The scope of the claims

1. a sphere filled with a hollow or transparent body provided with a reflecting member for totally reflecting light on the inner peripheral surface of the sphere;

A plurality of openings provided on the surface of the sphere and having a center line passing through the center of the sphere;

Optical fiber connection means provided in the opening,

The optical axis center line of the multimode optical fiber connected to the optical fiber connecting means passes through the center of the sphere, and any one or more of the plurality of openings is used as a light entrance and the other one or more openings An optical coupler for optical connection, optical branching, or optical assembly, characterized by having a light exit port.

2. a plurality of spheres filled with a hollow or transparent body provided with a reflecting member for totally reflecting light on the inner peripheral surface of the sphere;

A plurality of openings provided on the surface of each of the spheres, the center lines of which are formed so as to pass through the center of the sphere;

Optical fiber connection means provided in the opening,

The plurality of spheres are coupled through one of the openings, and the optical axis center line of the multimode optical fiber connected to the optical fiber connection means passes through the center of the sphere connected to the plurality of spheres. An optical connection, an optical branching or an optical assembly, characterized in that any one or more of any one of the plurality of openings in the sphere is a light entrance and the other one or more openings are a light exit. For optical coupler.

3. The optical coupler according to claim 2, wherein the plurality of spheres are directly connected to each other by being in close contact with each other at one of the openings.

4. The optical coupler according to claim 2, wherein the plurality of spheres are connected in a tuft shape via optical fibers connected to the respective optical fiber connecting means.

5. A reflective member for totally reflecting light is attached to the inner surface of the outer periphery of the sphere, and the inside of the sphere has a refractive index gradually changed toward the outer periphery at a position different from the center of the sphere. A sphere filled with a body,

The sphere is provided on the surface thereof, and has a center line formed so as to pass through the center of the sphere. Multiple openings,

An optical fiber connection means provided in the opening,

Light for optical connection, light branching, or light aggregation, wherein any one or more of the plurality of openings are light entrances and the other one or more openings are light exits.

/ ΤΠ 口

6. A reflective member for totally reflecting light is attached to the inner surface of the outer periphery of the sphere, and the inside of the sphere is transparent with its refractive index gradually changed toward the outer periphery at a position different from the center of the sphere. A sphere filled with a body,

Optical fiber connection means provided in the opening,

The plurality of spheres are coupled through one third of the openings, and any one or more of any one of the plurality of openings in the plurality of spheres is used as a light entrance and the other one or more An optical coupler for optical connection, optical branching, or light aggregation, wherein an opening is a light exit.

7. The optical connection, optical branching or optical assembly according to claim 5, wherein the refractive index of the transparent body is set so as to gradually increase from the center to the outer periphery. Optical coupler.

8. The optical connection, optical branching or optical assembly according to claim 5, wherein the refractive index of the transparent body is set so as to gradually decrease from its center toward the outer periphery. For optical coupler.

9. The optical coupler according to claim 6, wherein the plurality of spheres are directly connected to each other by being in close contact with each other at one of the openings.

10. The optical coupler according to claim 6, wherein the plurality of spheres are connected in a tuft via optical fibers connected to the respective optical fiber connecting means.

11. a sphere filled with a hollow or transparent body provided with a reflecting member for totally reflecting light on the inner peripheral surface of the sphere;

A plurality of openings provided on the surface of the sphere and having a center line passing through the center of the sphere; Magnetism generating means provided at a position facing the outer periphery of the sphere and arranged to refract incident light;

Optical fiber connection means provided in the opening,

12. A sphere filled with a hollow or transparent body provided with a reflecting member for totally reflecting light on the inner peripheral surface of the sphere;

Magnetism generating means provided at a position facing the outer periphery of the sphere and arranged to refract incident light;

Optical fiber connection means provided in the opening,

The plurality of spheres are coupled via one of the openings, and any one or more of any one of the plurality of openings in the plurality of spheres is used as a light entrance and the other one or more openings An optical coupler for optical connection, optical branching, or optical aggregation, wherein the optical coupler is a light exit port.

13. The optical coupler according to claim 12, wherein the plurality of spheres are directly connected to each other by being in close contact with each other at one of the openings.

14. The optical coupler according to claim 12, wherein the plurality of spheres are connected in a tuft via optical fibers connected to the respective optical fiber connecting means.

15. The material according to claim 1, 2, 5, 6, 6, 11, or 12, wherein the material of the transparent body is formed of a translucent substance such as an inorganic material oxide glass, high-purity glass, and plastic. An optical splitter / aggregator according to any one of the preceding claims.

16. The input port and the output port are formed by removing a part of the reflection member in a circular shape, and are formed as described in any one of claims 1, 2, 5, 6, 11, and 12. 2. The optical branching and collecting device according to 1.

17. The method according to claim 1, wherein the reflective member is attached to the surface of the transparent sphere by sputter coating or vacuum deposition. The optical splitter on board.

18. The method according to claim 1, wherein the reflection member is formed of a light-impermeable material in which a single-layer metal or a dissimilar metal is stacked on two or three layers. 13. The optical branching / aggregating device according to any one of 5, 6, 11, and 12.

19. The method according to claim 1, wherein one opening provided on the surface of the sphere is a light entrance, and another plurality of openings provided in a strip shape on the surface of the sphere is a light exit. 7. The optical branching and assembling device according to 6.

20. The method according to claim 1, wherein one opening provided on the surface of the sphere is a light emitting port, and another plurality of openings provided in a strip shape on the surface of the sphere is a light incident port. 6. The optical coupler according to 6.

21. The optical coupler according to claim 3, 9 or 13, wherein two or three of the spheres are connected in a state where the openings are in close contact with each other.

22. The optical coupler according to claim 19, wherein one opening of the one connected sphere is a light entrance, and all other openings are light exits.

23. The optical coupler according to claim 19, wherein one opening of the one connected sphere is a light exit, and all other openings are light entrances.