JP4674336B2 - Vector-controlled optical path switching method and optical path switching apparatus - Google Patents

Description

  The present invention relates to an optical path switching device and an optical path switching method used in the fields of optical communication and optical information processing.

  In order to cope with the explosive increase in network traffic accompanying the spread of the Internet and intranets within a company / home, there is a need for an optical path switching device (optical switch) that does not pass through an electrical signal, that is, an optical-optical direct switch. As an apparatus / method for switching an optical path, that is, an optical fiber, an optical waveguide, or a path of light propagating in space, for example, a space division type that switches an optical path in or between optical waveguides, and a plurality of multiplexed Wavelength-division multiplexing type that switches light of wavelength by dividing it into optical paths according to wavelength, time-division multiplexing type that switches the optical path of light that is time-division multiplexed every certain time, mirror or shutter for the optical path of light propagating in space There are known methods such as a free space type that spatially divides and synthesizes. Each of these methods can be multiplexed or used in combination.

  The space division type optical switch uses a directional coupler, makes a copy of an optical signal with an optical branching device, turns on and off the light with a gate element, and guides the waveguide at the intersection of the intersection or Y branch. Proposals have been made to transmit or reflect light propagating through a waveguide by changing the refractive index, but it is still in the research and development stage. It is said that a thermooptic effect by heating an electric heater is used to change the refractive index of the waveguide of a Mach-Zehnder interferometer type optical waveguide switch, but the response speed is about 1 millisecond. Not only is it slow, it has the disadvantage that an electrical signal must be used to operate the optical switch.

  The free space type optical switch includes a micro electro mechanical system (abbreviated as MEMS), an exciton absorption / reflection switch (abbreviated as Exciton Absorption Reflection Switch; EARS switch), and a multistage. Beam shifter type optical switches, hologram type optical switches, liquid crystal switches, and the like have been studied. These have problems such as the presence of mechanically movable parts and polarization dependence, and it cannot be said that they are still in practical use.

  On the other hand, an all-optical thermal lens forming element and a light control system that directly modulates the intensity and frequency of light with light using the change in transmittance and refractive index caused by irradiating the thermal lens forming element with light. There has been a great deal of research. With the aim of developing new information processing technology using all-optical optical elements, the present inventors have studied light control methods using organic nanoparticle photothermal lens forming elements in which organic dye aggregates are dispersed in a polymer matrix. (See Non-Patent Document 1). Currently, the control light (660 nm and 980 nm) is used to modulate the signal light (780 nm and 1550 nm). The control light and the signal light are coaxially and confocally incident and formed transiently by absorption of the control light. An element with the principle of operation that signal light is refracted by a thermal lens is developed, and a high-speed response of about 20 nanoseconds is achieved. The thermal lens forming element made of a photoresponsive composition is irradiated with control light, and the transmittance and / or refractive index of signal light in a wavelength band different from that of the control light is reversibly changed to thereby form the thermal lens forming element. A light control method for performing intensity modulation and / or light beam density modulation of the signal light that passes through the control lens, the control light and the signal light being respectively converged and irradiated onto the thermal lens forming element, and the control light And the optical paths of the control light and the signal light are adjusted so that regions having the highest photon density in the vicinity (beam waist) of each focus of the signal light overlap each other in the thermal lens forming element. A light control method is disclosed (see Patent Document 1 to Patent Document 7). The thermal lens forming element made of the photoresponsive composition is irradiated with control light and signal light having different wavelengths, and the wavelength of the control light is selected from a wavelength band absorbed by the photoresponsive composition, A thermal lens is formed reversibly based on a distribution of density change caused by a temperature rise generated in a region where the photoresponsive composition absorbs the control light and a peripheral region thereof, and the signal light transmitted through the thermal lens A light control method for performing intensity modulation and / or light beam density modulation is disclosed (see Patent Document 8). For example, a dye / resin film or a dye solution film is used as the thermal lens forming element, and the response time of the signal light to the control light irradiation at a control light power of 2 to 25 mW is described as less than 2 microseconds ( (See Patent Document 8). Here, the thermal lens effect means that molecules that absorb light in the central part of light absorption convert light into heat, and this heat is propagated to the surroundings, resulting in a temperature distribution. The refractive index of the light changes such that the refractive index changes spherically from the light absorption center to the outside, resulting in a distribution in which the refractive index at the light absorption center is low and the refractive index increases toward the outside, which functions like a concave lens. Indicates. The thermal lens effect has been used for a long time in the field of spectroscopic analysis, and now it is possible to perform ultrasensitive spectroscopic analysis that detects light absorption by a single molecule (Non-Patent Document 2 and Non-Patent Document). 3).

  These thermal lens methods are excellent in controlling light with light and can respond at high speed, but the shape of the light beam formed during control light irradiation becomes a donut shape, so that the coupling efficiency to the optical fiber is small. There is a problem of becoming.

  As a method for solving the above problems, the present inventors irradiate the light absorption layer in the thermal lens forming element including the light absorption layer with control light and signal light so as to converge at the light absorption layer, In addition, the control light and the signal light are irradiated such that the positions of the convergence points of the control light and the signal light are different from each other in the direction perpendicular to the optical axis. A refractive index is formed by a thermal lens that is reversibly formed by converging and then diffusing on the incident surface or inside thereof, due to the temperature rise occurring in the region where the control light is absorbed in the light absorption layer and its peripheral region. Is changed to change the traveling direction of the signal light, that is, deflect the optical path, the signal light that is not irradiated with the control light and the traveling direction is not changed, and the signal light that is irradiated with the control light and deflected in the optical path Detected separately And it filed an optical path switching method and switching device and said Rukoto (Japanese Patent Application No. 2006-046028 and Japanese Patent Application No. 2006-046029). In this method, the light beam shape of the signal light whose traveling direction is changed is not a donut shape, but the optical path is deflected in a state close to the original light beam shape, so that the coupling efficiency to the optical fiber is improved, and the light beam shape of the signal light is a donut shape. Can be higher than in the case of. In Japanese Patent Application No. 2006-046029, which is a more compact method capable of one input and multiple outputs, as an irradiation method of signal light and control light, a plurality of optical fibers are brought close to one ferrule, and the end faces of all the optical fibers are flush with each other. The signal light is emitted from one optical fiber, the control light is emitted from one optical fiber adjacent to the optical fiber, and a plurality of optical fibers are arranged on one ferrule on the signal light receiving side as well as the emission side. Are arranged so that the end faces of all optical fibers are in the same plane, and light is received by a specific optical fiber according to the presence or absence of control light irradiation. While this method has the merit that the device configuration can be made compact, signal light and control light are emitted, arrangement of a plurality of adjacent optical fibers, and signal light and optical path deflected signal that go straight without being irradiated with control light The arrangement of a plurality of optical fibers that receive light does not completely correspond to one to one, and a problem remains that signal light cannot be received efficiently.

  As a method of deflecting an optical path by using a thermal lens effect or a refractive index change due to heat, a method of deflecting light by applying heat to a medium with a heating resistor to generate a refractive index distribution in the medium is disclosed ( (See Patent Document 9). However, the above-described method inherently has a problem of “spreading of heat” because heat is generated by the heating resistor and the medium is heated by heat conduction. That is, due to the spread of heat, a fine thermal gradient cannot be given within a wide area, and it is difficult to obtain a desired refractive index distribution. Further, even if the photolithography technique used in the semiconductor integrated circuit is adopted for the fine processing of the heating resistor, there is a certain limit in practice, and the element must be enlarged. As the element becomes larger, the optical system becomes more complicated and larger. In addition, since the medium is heated by heat generation by generating heat with a heat generating resistor, the response is slow and the problem that the frequency of refractive index change cannot be increased is an essential problem.

  The thermal lens forming element comprising a photoresponsive composition and at least an intensity distribution adjusting means for irradiating the thermal lens forming element with light having a wedge-shaped light intensity, and forming the thermal lens with control light A deflecting element using a thermal lens forming element is disclosed in which a refractive index distribution is formed in the element, and signal light having a wavelength different from that of the control light is deflected by the refractive index distribution (patent) Reference 10). This method is excellent in that the light is controlled by light, but the loss of control light is large due to the intensity distribution adjusting means for irradiating the thermal lens forming element with the light intensity distribution of the wedge shape, In addition, it is difficult to freely form a wedge-shaped light intensity distribution, and there is a possibility that the optical path switching direction cannot be freely set.

  In addition, there has been proposed a method of deflecting laser light by changing the refractive index of the material irradiated with laser light by irradiating the laser light to heat the material (see Patent Document 11 and Patent Document 12). In both methods, the beam diameter is large, and the deflection of the laser beam is very small unless a large power is input. The method of Patent Document 11 is a method in which the irradiation light itself is deflected by heating the irradiation light. When this method is used for light deflection, the irradiation light is absorbed in order to change the refractive index by heating, so that the light transmitted through the substance is greatly reduced in principle.

  The method of Patent Document 12 is an optical switch that takes no electrical or mechanical means, changes the refractive index of the switch material by irradiation of a control beam, and changes the optical path of the signal beam. However, even in this case, neither the control beam nor the signal beam is collected using a lens, and the laser beam that causes the refractive index change requires a large power. In addition, the device becomes large.

  In both Patent Document 11 and Patent Document 12, the means for separating and condensing the non-deflected light and the deflected light as in the present proposal and the incidence of the non-deflected light and the deflected light on the optical fiber using the optical fiber as the light receiving means. No means for performing high-precision separation between unpolarized light and deflected light using the difference in angle is described.

  Patent Document 13 discloses a cylindrical photoconductor having a structure in which a plurality of optical fibers are regularly arranged, and a method for producing the photoconductor. However, nothing is said about the proposed light deflection and optical path switching.

Takashi Hiraga, Norio Tanaka, Kikuko Hayami, Tetsuro Moriya, Creation of dye aggregates / aggregates, structural evaluation, photophysical properties, "Electronics Research Institute Vocabulary", Ministry of International Trade and Industry 59, No. 2, pp. 29-49 (1994) Takao Fujiwara, Keiichiro Fuwa, Takayoshi Kobayashi, Laser-induced thermal lens effect and its application to colorimetric method, "Chemical", Kagaku Dojin, Vol. 36, No. 6, pp. 432-438 (1981) Takehiko Kitamori, Goro Sawada, Photothermal Conversion Spectroscopy, “Bunseki”, published by the Japan Society for Analytical Chemistry, March 1994, pp. 178-187 JP-A-8-286220 JP-A-8-320535 JP-A-8-320536 Japanese Patent Laid-Open No. 9-329816 Japanese Patent Laid-Open No. 10-90733 JP-A-10-90734 Japanese Patent Laid-Open No. 10-148852 Japanese Patent Laid-Open No. 10-148853 Japanese Patent Laid-Open No. 60-14221 JP-A-11-194373 US Pat. No. 4,776,677 US Pat. No. 4,585,301 Japanese Patent No. 2781710

  The present invention makes it possible to deflect light in an arbitrary direction with a small control light power without using complicated and expensive electric circuits and mechanical moving parts, so that failure is extremely low and durability is high. The optical path can be switched while maintaining a state where the energy distribution in the cross section of the signal light is easily converged optically (for example, a Gaussian distribution), and the light to the optical fiber in the subsequent stage can be switched. It is an object of the present invention to provide a compact optical path switching apparatus and optical path switching method capable of performing coupling with high efficiency and enabling one input and multiple outputs with a high extinction ratio.

  The present invention has the following features.

(1) The control light and the signal light are incident on the light absorption layer in the thermal lens forming element including at least the light absorption layer,
Two or more of the control lights are incident simultaneously,
In accordance with a desired optical path switching request, the presence or absence of irradiation and the irradiation intensity are determined for each of the two or more control lights,
The control light and the signal light are irradiated so as to converge at or near the light absorption layer, and the positions of the convergence points of the control light and the signal light are different in the direction perpendicular to the optical axis. Irradiated and
The wavelength of the control light is different from the wavelength of the signal light, the wavelength of the control light is selected from a wavelength band that is absorbed by the light absorption layer, and the wavelength of the signal light is from a wavelength band that is not absorbed by the light absorption layer. Chosen,
The control light and the signal light are converged and incident on the light absorption layer or in the vicinity thereof, so that the presence or absence of each of the two or more control lights in the light absorption layer and each According to the irradiation intensity, the direction of the signal light is changed by the refractive index change caused by the temperature rise occurring in the area where the control light is absorbed and the surrounding area, that is, the thermal lens,
The signal light whose traveling direction is changed in accordance with the presence / absence of each of the two or more control lights and the intensity of each of the control lights is incident on a specific light receiving means determined according to the desired optical path switching request. This is a vector-controlled optical path switching method.

  (2) The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed after being irradiated with the control light are apparently converged at or near the light absorbing layer. The vector-controlled optical path switching method according to (1), wherein the points are separated from each other.

  (3) The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed while being irradiated with the control light are converged or condensed by the same optical means, respectively, The vector-controlled optical path switching method as described in (1) or (2) above, wherein the light is received by a specific light receiving means determined in accordance with a desired optical path switching request.

  (4) The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed while being irradiated with the control light are converged or condensed by the same optical means, respectively, As described in any one of (1), (2), and (3) above, the light is received by an optical fiber provided as a specific light receiving means determined according to a desired optical path switching request. This is a vector-controlled optical path switching method.

(5) Appearance of signal light incident on the optical fiber, which is not irradiated with control light and whose signal direction is not changed, and one or more signal lights whose optical paths are switched in or near the light absorption layer wherein the convergence point distance is a distance obtained by dividing the imaging magnification of the optical means for converging or condensing the signal light to the optical fiber an optical fiber distance as the light receiving means, on SL (4) a vector controlled optical path switching method according to.

(6) a signal light source that emits signal light having one or more wavelengths;
Two or more control light sources that simultaneously emit control light having a wavelength different from that of the signal light,
A control light source that is irradiated with the presence or absence of irradiation and the irradiation intensity determined for each of the two or more control lights according to a desired optical path switching request;
A thermal lens forming element including a light absorbing layer that transmits the signal light and selectively absorbs the control light;
Condensing means for condensing the control light and the signal light in the light absorbing layer or in the vicinity thereof by converging each of the convergence points in a direction perpendicular to the optical axis,
The thermal lens forming element is configured such that the two or more control lights and the signal light are converged and incident on the light absorption layer or in the vicinity thereof, whereby the two or more control lights in the light absorption layer are incident. Depending on the presence / absence of each light irradiation and the intensity of each light irradiation, the signal light travel direction is changed by a refractive index change caused by a temperature rise that occurs in the region that absorbs the control light and its surrounding region, that is, a thermal lens. ,
A vector-controlled optical path switching device, comprising: a light receiving unit on which the signal light is selectively incident according to the desired optical path switching request.

  (7) The thermal lens formed in the light absorbing layer of the thermal lens forming element has a signal light whose traveling direction has not been changed without being irradiated with the control light and a signal whose traveling direction has been changed by being irradiated with the control light. The vector-controlled optical path switching device according to (6) above, wherein the light converging points with light or apparent convergence points in the vicinity thereof are separated from each other.

  (8) The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed while being irradiated with the control light are converged or condensed by the same optical means, respectively, The vector-controlled optical path switching device according to (6) or (7), wherein the light is received by a specific light receiving means determined in accordance with a desired optical path switching request.

  (9) The vector control type optical path switching device according to any one of (6), (7), and (8), wherein the detection means is an optical fiber.

(10) The apparent convergence point distance of the signal light incident on the optical fiber, the signal direction of which is not changed, and one or more signal lights whose optical paths are switched in the light absorption layer or in the vicinity thereof is received light characterized in that the optical fiber distance the signal light is a distance obtained by dividing the imaging magnification of the optical means for converging or focusing light to the optical fiber, an optical path switching device described above SL (9).

  According to the present invention, it is possible to locally increase the light power density by condensing the control light and irradiating the light absorption layer or the vicinity thereof, and increase the local temperature of the light absorption layer with low power. And the refractive index of the portion can be changed. In addition, by collecting the signal light and making it incident on the light absorption layer near the irradiation position of the control light, the change in the refractive index due to the control light can be used efficiently, and the vector can be obtained by simultaneously entering two or more control lights. The optical path switching direction can be freely controlled by the control type, and the optical path can be switched with high accuracy using the deflection of the signal light.

  Furthermore, since the deflected signal light is output from the thermal lens forming element in the same shape as the beam cross section before condensing, it is highly practical when the deflected signal light is subsequently condensed.

  Furthermore, a plurality of control lights can be incident on the same light absorption layer or in the vicinity thereof, and one input can be switched to a plurality of different optical paths by a vector control expression.

  In addition, since a plurality of control lights, signal lights, and a plurality of optical path switching signal lights can be incident and detected by adjacent optical fibers, a small and inexpensive apparatus can be provided.

  In the present invention, the control light and the signal light can be condensed and the light condensing points can be brought close to each other, so that the optical path can be switched at high speed.

  Further, since a low-power semiconductor laser can be used, a small and inexpensive apparatus can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings of FIGS.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an optical deflection type optical path switching device according to a first embodiment of the present invention. Here, the light travels along the light traveling direction 1001.

  2 schematically shows the light exit side end face of the seven-core optical fiber 120, and FIG. 3 schematically shows the incident side end face of the seven-core optical fiber 130. As shown in FIG.

  4a schematically shows the positional relationship between the 7-core optical fiber 120 and the hole 3 of the optical flat plate 4, and FIG. 4b schematically shows the spread of the signal light 1 and the control light 11 emitted from the light emitting side end face of the 7-core optical fiber 120. Shown in

  1, 2, 4 a, and 4 b, two or more single modes are used as light sources for emitting two or more lights having different wavelengths from the respective emission regions arranged on the same plane. Using a 7-core optical fiber 120 in which optical fibers are bundled and polished so that the light exit end faces of the optical fibers are flush with each other, the core of each optical fiber is used as the exit area, and the optical fiber core 100 exits the center of the 7-core optical fiber 120. The signal light 1 is emitted from the end face 101, and the control lights 11 and 12 and other four light beams (not shown) are respectively emitted from the emission end faces of the optical fiber cores 201, 202, 203, 204, 205 and 206 around the seven-core optical fiber 120. One or more of the control lights are emitted at the same time, and the signal light 1 and the control lights 11 and 12 or other four not shown. The control light has a different wavelength, and the signal light 1 passes through a hole 3 provided in the optical flat plate 4 for correcting the shift of the condensing point due to the difference in wavelength between the signal light and the control light, that is, chromatic aberration. The control lights 11 and 12 or the other four control lights (not shown) are transmitted through the optical flat plate 4 arranged in contact with the emission end face of the seven-core optical fiber 120, avoiding the holes 3, and the signal lights 1 and The control lights 11 and 12 or the other four control lights (not shown) pass through the condensing lenses 5 and 6 as optical means for image formation in common, and light from the light absorption layer 25 of the thermal lens forming element 7. The image is formed on the same plane on the incident side. The light absorption layer 25 of the thermal lens forming element 7 does not absorb the wavelength of the signal light 1 and has light absorption spectral characteristics such that the control lights 11 and 12 or the wavelengths of the other four control lights not shown are absorbed. Shall be used. When the control lights 11 and 12 or other four control lights not shown are not irradiated, the signal light 1 goes straight through the thermal lens forming element 7 and goes straight as the signal light 220, and the control lights 11 and 12 or other lights not shown. When four control lights are irradiated, the light absorption layer 25 of the thermal lens forming element 7 absorbs the control lights 11 and 12 or other four control lights (not shown) and the temperature rise that occurs in the peripheral area. The optical path of the signal light 1 is deflected by the refractive index change, that is, the refractive index distribution (which is referred to as the thermal lens effect) in which the refractive index becomes smaller in the region where the temperature is higher. The other four signal lights are not emitted. The signal light that has passed through the thermal lens element 7 is received by the condenser lenses 8 and 9, collimated, and then applied to one of the end faces of the optical fibers 300, 301, 302, 303, 304, 305, or 306 of the light receiving side optical fiber 130. The arrangement of the light receiving side optical fiber 130 and the intensity and intensity ratio of the control lights 11 and 12 or other four control lights (not shown) are adjusted so that the light is incident reliably. As described above, the optical path deflection of the signal light 1 is controlled by adjusting the intensity and intensity ratio of the one or more control lights 11 and 12 or the other four control lights (not shown). The method optical path switching method is called a vector control type.

  Here, the signal light 1 and the control lights 11 and 12 to the other four control lights (not shown) are first light-absorbed by the lenses 5 and 6 from the incident surface of the light-absorbing layer 25 in the light traveling direction by several hundred μm. It was made to converge at 25 or 25. The distance between the convergence points of the signal light and the control light was about 25 to 50 μm. Since the exit surface of the optical fiber is round, the shape of the signal light at the convergence (condensing) point is round. However, when the distance between the convergence points of the signal light and the control light is less than 25 μm, it does not become a round beam but a crescent moon beam. When the signal light of the crescent moon beam is subsequently condensed and incident on the optical fiber, the incident efficiency is reduced, which may impair practicality. Therefore, the distance between the convergence points of the signal light and the control light was adjusted to 25 to 50 μm as described above.

  As shown in FIG. 2, as the seven-core optical fiber 120 on the light emitting side, one end of seven single-mode optical fibers composed of a core and a clad made of two types of quartz glass having different refractive indexes are bundled, and a hole in the ferrule 121 And fixed with an adhesive 122 and polished so that the output end faces of the seven optical fibers are aligned and become the same plane. For example, the diameter of the central core 100 and the peripheral cores 201, 202, 203, 204, The diameters of 205 and 206 were all 9.5 μm, and the diameters of the central cladding 110 and the peripheral claddings 211, 212, 213, 214, 215, and 216 were all 39.0 μm. In this case, the center-center distance between the central core 100 and the peripheral cores 201, 202, 203, 204, 205, or 206 is 39.0 μm, and the center-to-center distance between adjacent peripheral cores is also 39.0 μm. . When a wavelength of 980 nm is used as the control light, the light is transmitted from the light source by a single mode optical fiber having a core diameter of about 6.5 μm and is transmitted to the peripheral cores 201, 202, 203, 204, 205 and 206 of the seven-core optical fiber 120. A corresponding unbound end (not shown) was attached. In this case, the length of the control light peripheral fiber of the seven-core optical fiber 120 was about 50 cm. Needless to say, as the seven-core optical fiber 120 on the light emitting side, the diameter of the central core 100 may be 9.5 μm, and the diameters of the peripheral cores 201, 202, 203, 204, 205 and 206 may all be about 6.5 μm.

  The seven single-mode optical fibers constituting the seven-core optical fiber 120 were used by etching a quartz optical fiber cladding layer to a desired thickness with hydrofluoric acid. The portion to be etched was a few mm of the tip of the optical fiber. The thickness of the optical fiber after etching was calculated from a desired distance perpendicular to the optical axis of the convergence (condensation) point of the signal light and control light converged (condensed) on the light absorption layer 25. In the present embodiment, the diameter of the optical fiber after etching is 39.0 μm.

  One end (not shown) of the seven-core optical fiber 120 that is not bundled is independent of all seven, the clad diameter is 125 μm, and the central optical fiber is one light source of signal light 1 (see FIG. The peripheral six optical fibers are respectively connected to control lights 11 and 12 or other four control light sources (not shown) (not shown).

  As the light source of the signal light 1, for example, one semiconductor laser having an oscillation wavelength of 1550 nm and an output of 1 to 20 mW was used. The signal light may have any wavelength as long as it transmits the light absorption layer 25 of the thermal lens forming element 7.

  As the light sources of the control lights 11 and 12 to the other four control lights (not shown), for example, a maximum of six semiconductor lasers having an oscillation wavelength of 980 nm and an output of 10 to 50 mW were used. The number of light sources for the control light is arbitrarily selected in the range of 1 to 6 depending on the application. As for the wavelength of the control light, any wavelength can be used as long as it is absorbed by the light absorption layer 25 of the thermal lens forming element 7. However, since the chromatic aberration of the signal light and the control light is corrected by a method using one optical flat plate 4 as will be described later, the wavelengths of the control lights 11 and 12 and the other four control lights not shown are almost all. It is preferable that they are the same.

  The thermal lens forming element 7 can hold a liquid film having a thickness of 500 μm by precisely polishing a fused quartz glass having a diameter of 10 mm and an inner diameter of 8 mm on a quartz glass round plate having a diameter of 10 mm and a thickness of 1 mm. The dye solution described later was put into the product processed as described above, and another quartz glass having a diameter of 10 mm and a thickness of 1 mm was bonded with an ultraviolet curable resin.

  As the light absorption layer 25 of the thermal lens forming element 7, for example, infrared absorption cyanine dye 8- [2-Chloro-3- (2,4-diphenyl-6,7-dihydro-5H-chromone-8-ylmethylene) -cyclohex-1-enylmethylene] -2,4-diphenyl-5,6,7,8-tetorahydro-chromenylium perchlorate dissolved in 1,2-dichlorobenzene at 0.2% by weight with a cell gap of 500 μm The quartz cell was used by filling. The material of the light absorption layer in the thermal lens forming element used in the light deflection method and the light deflection apparatus of the present invention, the wavelength band of the signal light, and the wavelength band of the control light may be a combination of these depending on the purpose of use. Appropriate combinations can be selected and used. As a specific setting procedure, for example, first, the wavelength or wavelength band of signal light is determined according to the purpose of use, and a combination of the material of the light absorption layer film and the wavelength of control light that is optimal for controlling this is selected. It only has to be selected. Alternatively, after determining the combination of the wavelengths of the signal light and the control light according to the purpose of use, a material for the light absorption layer film suitable for this combination may be selected. For example, when an image or a character is to be directly displayed using signal light, visible light having a wavelength of 400 to 800 nm is used as signal light, infrared light having a wavelength of 980 nm is used as control light, and the light absorbing layer material is the above-described material. A material that transmits visible light having a wavelength and absorbs infrared light having the wavelength is used. In addition, for example, when light having a wavelength corresponding to the longest wavelength λ1 of the absorption maximum in the light absorption spectrum of the material of the light absorption layer to be used is used as control light, light having a wavelength longer than λ1 is preferably used as signal light. Can do. Specifically, when perylene is used as the material of the light absorption layer, the control light can be 405 nm, for example, and the signal light can be 540 nm, 660 nm, 780 nm, 830 nm, 980 nm, 1310 nm, or 1550 nm. When a copper phthalocyanine derivative is used as the material of the light absorption layer, the control light can be set to 650 nm, for example, and the signal light can be set to 690 nm, 780 nm, 830 nm, 980 nm, 1310 nm, or 1550 nm, for example. Specific examples of the dye used for the light absorption layer 25 of the thermal lens forming element 7 include, for example, xanthene dyes such as rhodamine B, rhodamine 6G, eosin and phloxine B, acridine dyes such as acridine orange and acridine red, and ethyl. Azo dyes such as red and methyl red, porphyrin dyes, phthalocyanine dyes, cyanine dyes such as 3,3′-diethylthiacarbocyanine iodide, 3,3′-diethyloxadicarbocyanine iodide, ethyl violet, Triarylmethane dyes such as Victoria Blue R, naphthoquinone dyes, anthraquinone dyes, naphthalene tetracarboxylic acid diimide dyes, perylene tetracarboxylic acid diimide dyes, and the like can be suitably used. Moreover, these pigment | dyes can be used individually or in mixture of 2 or more types. As the solvent, a solvent that dissolves at least the dye to be used can be used. However, the temperature (boiling point) of boiling without being thermally decomposed when the temperature rises during the formation of the thermal lens is 100 ° C. or higher, preferably 200. Those having a temperature of at least ° C, more preferably at least 300 ° C can be suitably used. Specifically, inorganic solvents such as sulfuric acid, halogenated aromatic hydrocarbons such as o-dichlorobenzene, aromatic substituted aliphatics such as 1-phenyl-1-xylylethane or 1-phenyl-1-ethylphenylethane Organic solvents such as hydrocarbons and nitrobenzene derivatives such as nitrobenzene can be suitably used.

  When the light absorption layer 25 of the thermal lens forming element 7 absorbs the control lights 11 and 12 or other four control lights (not shown), the temperature of the light absorption layer rises and the refractive index changes. As the temperature increases, the refractive index generally changes in a decreasing direction. The intensity distribution of laser light emitted from a normal laser light source and laser light emitted from a normal laser light source and transmitted through an optical fiber is a Gaussian distribution. Further, the light obtained by condensing the laser light with a lens or the like has a Gaussian distribution. Therefore, in the refractive index distribution in the light absorption layer irradiated with the control light, the refractive index is the lowest on the optical axis of the control light, and the refractive index is less reduced around the control light. Further, since there is heat conduction, the refractive index changes even in a portion where light is not irradiated.

  5a, 5b, and 5c are diagrams illustrating a situation in which signal light is deflected. For the sake of simplicity, in FIGS. 5a, 5b, and 5c, light refraction due to the difference in refractive index between the light absorbing layer and the medium around the light absorbing layer is ignored. 5a, 5b, and 5c, in the light absorption layer 25 of the thermal lens forming element, the light intensity distribution 29 of the control light in the vicinity of the convergence (condensation) point, and the control light away from the convergence (condensation) point. The light intensity distribution 30 is shown, and the convergence (condensation) point 31 of the control light, the convergence (condensation) point 33 of the signal light when the control light is not irradiated, and the light deflected by the control light irradiation are on the light receiving side. In the figure, an apparent signal light convergence (condensation) point 32 that appears to have originated from there is shown. FIG. 5A shows the case where the control light and the signal light are converged (condensed) on the incident surface of the light absorbing layer 25. FIG. 5B shows the case where the control light and the signal light are in the light absorbing layer 25 from the incident surface of the light absorbing layer. 5c converges (condenses) when the control light and the signal light have traveled into the light absorption layer 25 more than several tens of μm from the incident surface of the light absorption layer. The optical path of the laser beam in this case is schematically shown.

  When the control light is not irradiated, the signal light goes straight. When the control light is irradiated, the signal light is deflected. The signal light transmitted through the light absorption layer 25 is reflected on the end faces of the individual optical fibers 130 of the light receiving side seven-core optical fiber 130 shown in FIG. Converges (condenses) as if the signal light was emitted from. In the case of FIG. 5b, the convergence (condensation) point 33 of the signal light almost coincides with the apparent convergence (condensation) point 32 of the signal light, but the cases of FIGS. 5a and 5c are shifted. The direction of deviation is opposite in the case of FIG. 5a and FIG. 5c.

  As the condenser lenses 5 and 6, both aspherical lenses having a focal length of 2 mm were used. In the present embodiment, the condensing (imaging) magnification is 1. One single lens may be used instead of the condenser lenses 5 and 6. In any case, unless you use a large chromatic aberration correction lens that combines multiple convex and concave lenses with different refractive indexes, the shorter the wavelength, the closer the focal point is to the focal point, due to the refractive index wavelength dispersion of the lens component material. However, it is unavoidable that the chromatic aberration that the focal point becomes farther as the light becomes longer. Also in the present embodiment, the first lens 5 having a focal length of 2 mm and the second lens 6 having a focal length of 2 mm are used to convert the signal light having a wavelength of 1550 nm and the control light having a wavelength of 980 nm emitted from the same surface to the thermal lens forming optical element 7. However, the condensing point of the signal light and the control light is shifted by about 50 μm in the light traveling direction. If the light is collected by a single lens with a focal length of 2 mm, the amount of deviation will be approximately double this. When such a condensing point position shift occurs between the signal light and the control light, the signal light is not yet fully collected in the vicinity of the condensing point of the control light having a large refractive index change in the light absorption layer. The influence of the refractive index on the signal light varies depending on the cross-sectional position perpendicular to the optical axis, and the signal light distribution deviates greatly from the Gaussian distribution. As a result, the deflection efficiency is deteriorated as a whole.

  Therefore, in the present embodiment, the signal light 1 passes through the hole 3 provided in the optical plate 4 for correcting the shift of the condensing point due to the difference in wavelength between the signal light and the control light, that is, chromatic aberration. The control light 11 is transmitted through the optical flat plate 4 disposed in contact with or close to the exit end face of the seven-core optical fiber 120 while avoiding the hole 3. The hole 3 is preferably tapered in accordance with the opening angle of the signal light 1 emitted from the light emitting end face 101 of the core 100. In addition, as a method for processing the hole 3 in the optical flat plate 4, a sandblasting method, an excimer laser ablation method, or the like is preferably used. In any case, a tapered hole is formed rather than a hole having a constant diameter. Opening is easier to process. Incidentally, when an excimer laser of argon fluoride (ArF) is used, a hole having a diameter of several μm can be formed.

  FIG. 4 a shows the positional relationship between the tapered hole 3 provided in the optical flat plate 4 and the emission side end face of the seven-core optical fiber 120. Needless to say, the tapered hole 3 has a small hole 41 adjacent to the output side end face of the seven-core optical fiber 120 and a large output side hole 42 of the optical flat plate 4. Since the core diameter of the seven-core optical fiber 120 is 9.5 μm and the cladding diameter is 39.0 μm, the diameter of the hole 41 is preferably 10 to 20 μm and the diameter of the hole 42 is preferably about 40 μm. In order to prevent interference between the tapered hole 3 and the signal light 1 emitted while expanding, the thickness t of the optical flat plate 4 may be set to satisfy the following formula [1].

t ≦ (dc) / 2N (1)
(Where c is an average diameter when the exit area is approximated to a circle [core diameter of optical fiber], d is an average distance between the exit areas approximating a circle [distance between adjacent cores], and N is the exit area. (Numerical aperture of light emitted from [core].)

  The numerical aperture N of a single mode optical fiber is usually about 0.11. Therefore, in this embodiment, if d is 39.0 μm and c is 9.5 μm, t may be 134 μm or less.

  On the other hand, the thickness t of the optical flat plate 4 necessary for correcting the chromatic aberration (the focal point of the signal light and the control light is about 50 μm in the light traveling direction) is 980 nm as the material of the optical flat plate 4. When a high refractive index of 1.883 is used, 100 μm is sufficient. This value also satisfies the above equation [1]. Needless to say, in order to maximize the effect of correcting the chromatic aberration with respect to the control light (980 nm), it is preferable to pass the signal light (1550 nm) through the air (hole 3) having a refractive index of 1.

  The core diameter of the single mode optical fiber used is 9.5 μm and can be regarded as a point light source. Since the numerical aperture of the single mode optical fiber used is about 0.11, the signal light 1 from the core 100 of the optical fiber 120 is optical when the optical flat plate 4 for correcting chromatic aberration is brought into close contact with the light emitting end face of the optical fiber 120. The thickness of the signal light on the emission surface of the flat plate 4 (surface opposite to the optical fiber) is about 30 μm. As described above, since the hole of about 40 μm is formed in the exit surface of the optical flat plate 4, the signal light 1 can pass through the hole 3 without interfering with the optical flat plate 4.

  As shown in FIG. 4 b, the signal light passes through the hole of the optical flat plate 4 from the emission end face 101 of the core 100 and is emitted directly into the air. On the other hand, the control light 11 passes from the end surface 2011 of the core 201 through the optical plate 4 having a higher refractive index than the core material, and then exits from the exit surface 2112 of the optical plate 4 into the air. Therefore, as a result of the control light passing through the optical flat plate 4 having a higher refractive index than air, it appears that the control light is emitted from a position where the light travels in the traveling direction of about 50 μm, and the chromatic aberration (signal light and control light The condensing point is corrected by about 50 μm in the light traveling direction. With respect to the control light 12 or other four control lights (not shown), the chromatic aberration is corrected in the same manner as the control light 11.

  In this embodiment, the emitted light from the central core 100 is 1550 nm, and the emitted lights from the peripheral cores 201, 202, 203, 204, 205 and 206 are 980 nm. Therefore, the emitted light 1550 nm from the central core 100 is an optical flat plate. 4 so that the light 980 nm emitted from the peripheral cores 201, 202, 203, 204, 205, and 206 can pass through the hole 3. However, conversely, when the wavelength of the light emitted from the central core is shorter than the wavelength of the light emitted from the peripheral core, it is necessary that the optical plate passes only the light emitted from the central core.

  The lens 8 was an aspherical lens having a focal length of 2 mm and the lens 9 having a focal length of 2.75 mm. In the present embodiment, the signal light is converged (condensed) by two lenses, but it goes without saying that the signal light may be converged (condensed) by one lens. The focal lengths need not be 2 mm and 2.75 mm, but the focal lengths are the same as those described above because of the size reduction, separation of the signal light incident on the light receiving side end face of the 7-core optical fiber 130 and the incidence efficiency. I decided to use it. Here, the imaging magnification formed by the lens 8 and the lens 9 is 1.375.

  Although not described in FIG. 1 of the present embodiment, the control light is cut when the control light passes through the thermal lens forming element 7 and is incident on the light receiving side seven-core optical fiber 130 and affects the subsequent mechanism. Then, a wavelength selection filter that transmits signal light may be installed between the thermal lens forming element 7 and the light receiving side seven-core optical fiber 130.

  As shown in FIG. 3, as the seven-core optical fiber 130 on the light receiving side, as in the case of the seven-core optical fiber 120 on the light emitting side, a single core composed of two types of quartz glass and clad having different refractive indexes is used. One end of seven mode optical fibers is bundled, inserted into a hole of a ferrule 131, fixed with an adhesive 132, and polished so that the incident end surfaces of the seven optical fibers are aligned and become the same plane. The diameters of the peripheral cores 301, 302, 303, 304, 305 and 306 are all 9.5 μm, and the diameters of the central cladding 310 and the peripheral claddings 311, 312, 313, 314, 315 and 316 are all 39.0 μm. It was. In this case, the distance between the core centers of the central core 300 and the peripheral cores 301, 302, 303, 304, 305 or 306 is 39.0 μm, and the distance between the centers of adjacent peripheral cores is also 39.0 μm. .

  As in the case of the seven-core optical fiber 120, the seven single-mode optical fibers constituting the seven-core optical fiber 130 are obtained by etching the clad layer of a single-mode quartz optical fiber having a core diameter of 9.5 μm to a desired thickness with hydrofluoric acid. Using. The portion to be etched was a few mm of the tip of the optical fiber.

  The clad diameter of the single mode optical fiber after etching was calculated from a desired distance perpendicular to the optical axis of the convergence (condensation) point of the signal light and control light converged (condensed) on the light absorption layer 25. In the present embodiment, the clad diameter ω of the optical fiber after etching is 39.0 μm. The cladding diameter ω of the optical fiber after etching is expressed by a distance χ in the direction perpendicular to the optical axis between the convergence point 33 of the signal light converged (condensed) on the light absorption layer 25 and the convergence point 32 of the apparent signal light. There is a relationship of [2].

ω = mχ [2]
Here, m is an imaging magnification formed by the lens 8 and the lens 9 shown in FIG. In the present embodiment, m = 1.375, but the imaging magnification m may be set so that the incident efficiency to the seven-core optical fiber 130 is maximized.

The above χ can be changed by changing the following conditions.
1. 1. Position of light absorption layer of thermal lens forming element with respect to convergence (condensation) point of signal light and control light. 2. Control light power Control light position (distance perpendicular to the optical axis of the condensing point of signal light and control light at or near the light absorption layer)
4). 4. The thickness of the light absorption layer of the thermal lens forming element 5. Control light wavelength and signal light wavelength Dye concentration in the light absorption layer

  One end (not shown) of the light-receiving-side seven-core optical fiber 130 that is not bundled is independent of all seven, the clad diameter is 125 μm, and each of the seven independent optical fibers is, for example, Signal light that is connected to a photodetector such as a photodiode and whose optical path is switched to seven optical fibers is received and detected.

  In addition, if there is a photodetector that can be installed with the interval of seven independent light receiving parts approaching about 40 μm instead of the light receiving side seven-core optical fiber 130, the signal light whose optical path is switched can be obtained even if it is used. The state of the optical path switching can be detected.

  The position adjustment of the light-receiving side 7-core optical fiber 130 and the adjustment for improving the efficiency of incidence on the seven optical fiber end faces were performed in the following procedure.

  The position of the core 300 end face and the optical axis of the center fiber of the light receiving side seven-core optical fiber 130 are first adjusted so that unpolarized light, that is, the straight signal light 220 can be received efficiently, and then the center of the light receiving side seven core optical fiber 130 is adjusted. The mounting azimuth angle of the light receiving side 7-core optical fiber 130 is adjusted with the axis as the rotation axis, and then the control lights 11 and 12 emitted from the peripheral optical fibers of the light emitting side 7-core optical fiber or other four control lights (not shown) Increasing the incident efficiency of the light-receiving side seven-core optical fiber 130 to a specific optical fiber core was adjusted by adjusting the intensity and the intensity ratio.

The arrangement of the cores 100 and 201 to 206 of the light emitting side seven-core optical fiber shown in FIG. 2 and the arrangement of the cores 300 and 301 to 306 of the light receiving side light emitting side seven core optical fiber shown in FIG. Since the center position of each core is shifted by about 0.1 to 1 μm, for example, when the control light 11 is emitted only from the core 201, the control light 11 is difficult to manufacture as a “regular hexagon”. By adjusting only the intensity 11, the signal light 1 emitted from the core 100 can be received as the deflected signal light 221 by, for example, the specific optical fiber core 304 of the light-receiving side seven-core optical fiber 130 almost completely. Although it is possible to finely adjust the mounting azimuth angle of the light-receiving side 7-core optical fiber 130, When the control lights 11 and 12 or the other four control lights (not shown) are emitted from “only one” of the lamps 202 to 206 when the intensity is carefully controlled, the deflected signal lights (for example, 222) ) Is not easily received by only one specific optical fiber core (for example, 303) of the seven-core optical fiber 130 on the light receiving side. Therefore, control light with carefully adjusted intensity is emitted from “only one” of cores 202 to 206 other than core 201 from “adjacent one” to realize vector control using two control lights. Thus, the deflected signal light (for example, 222) can be completely received by a specific one (for example, 303 ) of the optical fiber core of the light receiving side seven-core optical fiber 130. Table 1 shows an example of the output side control optical fiber number, the control light power, and the light receiving side optical fiber incident signal intensity. In Table 1, -99 dB is described as the output below the detection limit of the measuring instrument.

  In the adjustment example shown in Table 1, the control lights 11 and 12 are applied to the incident signal intensity of 10.3 dB to the core 300 of the central fiber of the light receiving side seven-core optical fiber 130 when the control light is not irradiated. When the incident light intensity is 6.7 dB to the core 304 of the light-receiving-side seven-core optical fiber 130 and is incident on another specific core, the control lights 12 and 13, 13 and 14, 14 and 15, 15 And 16 or 16 and 11 are simultaneously irradiated, and the incident intensity to a specific core (304, 303, 302, 301, 306 or 305, respectively) of the light receiving side seven-core optical fiber 130 is 6 by vector control. The two control light intensities simultaneously irradiated are adjusted as shown in Table 1 so as to achieve .1 to 6.7 dB. The control lights 13, 14, 15, and 16 are control lights emitted from the peripheral cores 203, 204, 205, and 206 of the seven-core optical fiber 120, respectively.

  In the case of the adjustment example in Table 1, as the so-called “crosstalk”, for example, when the control lights 11 and 12 are irradiated, the weak signal light is detected even in the cores 300, 305, and 306 other than the core 304. The extinction ratio is [(−35 to 37) −6.7] dB, that is, −41 to 43 dB, which sufficiently satisfies the practical extinction ratio (−35 dB). The crosstalk in other cases does not exceed -40 dB.

  The light receiving adjustment of the non-polarized light, that is, the straight signal light 220 is adjusted only by adjusting the position and the optical axis of the core 300 end face of the center fiber of the light receiving side seven-core optical fiber 130. After adjusting the position and the optical axis of the end face of the core 300 of the center fiber, the intensity and intensity ratio of 11 and 12 emitted from the peripheral optical fiber of the 7-core optical fiber on the light output side or other four control lights (not shown) are adjusted. Thus, it is possible to improve the incident efficiency of the light receiving side seven-core optical fiber 130 to the central optical fiber core.

  FIG. 6 shows the position of incidence (light absorption layer position) of the convergence (condensation) point of the signal light and control light on the light absorption layer 25 of the thermal lens forming element 7 shown in FIGS. An example of measurement data of a separation distance between non-deflected light and deflected light at the position of the device is shown. In FIG. 6, the light absorption layer position of 0 μm is the incident surface of the light absorption layer, and the plus direction is the light traveling direction. In the case of FIG. 6, the separation distance is close to 0 when the incident position (that is, the light absorption layer position) of the convergence (condensing) point of the signal light and the control light to the light absorption layer 25 is 40 to 60 μm. This is the case in the state of FIG. 5b. When the incident position on the light absorption layer 25 is deviated from this, the separation distance increases. When the incident position on the light absorption layer 25 (light absorption layer position) was 200 μm or more, there was no significant change in the separation distance. However, the deflected beam shape was better when the incident position (light absorption layer position) was 500 μm or more. In FIG. 6, the thickness of the light absorption layer 25 is 1000 μm, but even when the light absorption layer 25 is thinner, for example, 500 μm, the same value as in FIG. 6 is shown. It was. That is, even when the thickness of the light absorption layer 25 is 500 μm, the value at the light absorption layer position of 1000 μm (500 μm outside the light absorption layer 25) is almost the same value. This is presumably because the control light is almost absorbed by 500 μm or more and the influence on the light deflection amount is small. In FIG. 6, the positive and negative signs of the separation distance are such that the incident point of the signal light to the light absorption layer 25 is the origin (that is, 0 point) and the deflection direction is positive. The separation distance becomes positive in the state of FIG. 5c, and becomes negative in the state between FIGS. 5a and 5b. The data in FIG. 6 is an example when the focal lengths of the lenses 5, 6, 8, and 9 in FIG. 1 are all 8 mm, but there is no significant difference even in the case of the present embodiment.

  In FIG. 6, a line 38 (solid line connecting diamond points) has a control light power of 15.4 mW, a line 39 (solid line connecting square points) has a control light power of 18 mW, and a line 40 (solid line connecting triangle points) is In this case, the control light power is 20.5 mW. In the measurement of FIG. 6, the thickness of the light absorption layer is 1000 μm, the control light position (distance perpendicular to the optical axis of the signal light and the control light at the condensing point of the first condenser lens 6) is 25 μm, and the dye The concentration was 0.1%, and the light absorption layer had a transmittance of 95% at a wavelength of 1550 nm and a transmittance of 0.1% at 980 nm.

(Comparative Example 1)
In the first embodiment, an experiment similar to that of the first embodiment was performed except that the lens 5 was not used and the signal light and the control light were irradiated to the thermal lens forming element 7 without converging. However, when the control light power is about 18 mW, no deflection of the signal light was observed even when the control light was irradiated. Therefore, when the control light source is changed to Ti: cypher laser and further irradiated with high-power control light (980 nm), the solvent of the dye solution in the thermal lens forming element is detected before the deflection of the signal light is detected. It was confirmed that it was difficult to start boiling and deflect the signal light. Furthermore, the power of the control light was lowered to just before the start of boiling, and the arrangement of the signal light and control light and the distance between the beams until entering the thermal lens forming element were finely adjusted, but the optical path deflection of the signal light was observed. There wasn't. Furthermore, although the arrangement of the signal light and the control light in the light absorption layer in the thermal lens forming element and the distance between the beams were finely adjusted, no optical path deflection of the signal light was observed. That is, when the control light is converged and diffused in the light absorbing layer in the thermal lens forming element so that light absorption does not occur, and it is irradiated as a collimated parallel beam, it is large enough to deflect the optical path of the signal light. The thermal lens is not formed.

(Second Embodiment)
FIG. 7 is a schematic configuration diagram of an optical deflection type optical path switching device according to the second embodiment of the present invention. In the second embodiment of the present invention, the same optical members as those in the first embodiment are given the same numbers.

  7 is provided with a mirror 17 on the exit side of the condenser lens 8 and condenser lenses 18 and 19 on the exit side of the mirror 17, respectively. 1 has the same configuration as that of the deflection optical path switching apparatus according to the first embodiment shown in FIG. 1 except that single-mode optical fibers 20 and 21 for receiving the respective signal lights are provided. Further, the wavelength of the signal light used was 1550 nm, and the wavelength of the control light was 980 nm. However, it goes without saying that the wavelength of the signal light and the wavelength of the control light may be other wavelengths as in the first embodiment.

  In FIG. 7, signal light 1 is emitted from the emission end face 101 of the optical fiber core 100 at the center of the 7-core optical fiber 120, and the optical fiber cores 201, 202, 203, 204, 205, and 206 around the 7-core optical fiber 120. For example, the control lights 11 and 12 are simultaneously emitted from the emission end faces of the cores 201 and 202, the signal light 1 and the control lights 11 and 12 have different wavelengths, and the signal light 1 is the wavelength of the signal light and the control light. The control lights 11 to 12 are arranged in contact with the exit end face of the seven-core optical fiber 120 so as to pass through the hole 3 provided in the optical flat plate 4 for correcting the deviation of the condensing point, that is, the chromatic aberration. The optical plate 4 is transmitted through the hole 3 so that the signal light 1 and the control lights 11 and 12 are collected as a common optical means for image formation. Passes through the lens 5 and 6, is imaged on the incident surface or the light-absorbing layer 25 of the light absorbing layer 25 of the thermal lens forming device 7. The light absorption layer 25 of the thermal lens forming element 7 has a light absorption spectrum characteristic that does not absorb the wavelength of the signal light 1 and absorbs the wavelengths of the control lights 11 and 12. When the control lights 11 and 12 are not irradiated, the signal light 1 travels straight through the thermal lens forming element 7 and travels straight as the signal light 220, and when the control lights 11 and 12 are irradiated, the light absorbing layer of the thermal lens forming element 7. By the refractive index change accompanying the temperature rise occurring in the area where the control light 11 and 12 is absorbed by 25 and the peripheral area thereof, that is, by the refractive index distribution (this is referred to as the thermal lens effect) in which the refractive index decreases as the temperature increases. The signal light 1 is emitted as signal light 221 whose optical path is deflected and deflected. The signal light that has passed through the thermal lens element 7 is collimated by the condenser lens 8. When the control lights 11 and 12 are not irradiated, the signal light 1 travels straight without being reflected by the mirror 17, is collected by the condenser lens 18, and enters the single mode optical fiber 20. When the control lights 11 and 12 are irradiated, the signal light 1 is optically deflected, reflected by the mirror 17 as the signal light 221, condensed by the condenser lens 19, and enters the single mode optical fiber 21. The azimuth angle is adjusted and the positions and inclinations of the single-mode optical fibers 20 and 21 are adjusted with the central axis of the seven-core optical fiber 120 as the rotation axis so that the incidence efficiency to the single-mode optical fiber is maximized. By adjusting the strength, the adjustment can be performed more easily and accurately.

  In FIG. 7, the signal light 1 and the control lights 11 and 12 are emitted from a seven-core optical fiber, but a three-core optical fiber 140 shown in FIG. 8 may be used. For example, the signal light 1 is emitted from the core 400, and the control lights 11 and 12 are emitted from 401 and 402. In FIG. 8, as the three-core optical fiber 140, one end of three single-mode optical fibers composed of a core and a clad made of two types of quartz glass having different refractive indexes are bundled and inserted into a hole of a ferrule 141 and bonded. It is fixed with the agent 142 and polished so that the output end faces of the three optical fibers are aligned and become the same plane. For example, the diameter of the core 400 is about 9.5 μm, the diameter of 401 to 402 is about 6.5 μm, The diameters of the clads 410 to 412 are all 39.0 μm. In this case, the distance between the cores is also 39.0 μm.

  The present invention can be effectively used in the fields of optical communication and optical information processing.

1 is a schematic configuration diagram of an optical deflection type optical path switching device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line A-A ′ of FIG. 1, schematically illustrating a light emission side end surface of a seven-core optical fiber 120. FIG. 2 is a cross-sectional view taken along line B-B ′ in FIG. 1, schematically showing a light receiving side end face of a seven-core optical fiber 130. FIG. 4 is a diagram illustrating a positional relationship between a tapered hole 3 provided in an optical flat plate 4 and an emission side end face of a seven-core optical fiber 120. 4B is a cross-sectional view taken along line C-C ′ in FIG. 4A, schematically illustrating the spread of the signal light 1 and the control light 11 emitted from the light emission side end surface of the seven-core optical fiber 120. It is a figure explaining deflection of signal light. It is a figure explaining deflection of signal light. It is a figure explaining deflection of signal light. It is a graph which shows the relationship between the separation distance of non-deflected light and deflected light. It is a schematic block diagram of the light deflection type optical path switching device concerning a 2nd embodiment of the present invention. 3 is a diagram schematically illustrating a light emission side end face of a three-core optical fiber 140. FIG.

Explanation of symbols

  1 signal light emitted from the central core 100 of the 7-core optical fiber 120, 2 signal light deflected in the optical path by the thermal lens forming element 7, 3 holes provided in the optical flat plate 4, 4 optical flat plates, 5, 6 condenser lenses, 7 thermal lens forming element, 8, 9 condensing lens, 11, 12 control light emitted from peripheral cores 201, 202 of 7-core optical fiber 120, 17 mirror, 18, 19 condensing lens, 20, 21 single mode optical fiber, 25 Light absorption layer, 29 Light intensity distribution of control light near the convergence (condensation) point, 30 Light intensity distribution of control light away from the convergence (condensation) point, 31 Convergence (condensation) of control light Point, 32 Signal light deflected by irradiation with control light appears to converge from the light receiving side as if apparently converged (condensed), and 33 control light is not emitted. Signal light convergence (condensation) point, 38 solid line connecting diamond points, 39 solid line connecting square points, 40 solid line connecting triangle points, 41 tapered hole (small), 42 tapered hole (large) , 100 7-core optical fiber 120 central core, 101 core 100 emitting end face, 110 7-core optical fiber 120 center clad, 120 light emitting side 7-core optical fiber, 121 7-core optical fiber 120 ferrule, 122 adhesive, 130 light receiving side 7-core optical fiber, 131 7-core optical fiber 130 ferrule, 132 adhesive, 140 3-core optical fiber, 141 3-core optical fiber 140 ferrule, 142 adhesive, 201, 202, 203, 204, 205, 206 7-core optical fiber 120 Peripheral core, 211, 212, 213, 214, 215, 21 7-core optical fiber 120 peripheral cladding, 221 and 222 signal light deflected by the thermal lens forming element 7, 300 7-core optical fiber 130 central core, 301, 302, 303, 304, 305, 306 7-core optical fiber 130 periphery Core, 310 7-core optical fiber 130 center clad, 311, 312, 313, 314, 315, 316 7-core optical fiber 130 peripheral clad, 400, 401, 402 3-core optical fiber 140 core, 410, 411, 412 3-core optical fiber 140 clad, 1001 traveling direction of light, 2011 exit end face of peripheral clad 201 of seven-core optical fiber 120, 2112 exit surface of control light 11 exiting from optical flat plate 4.

Claims (10)

Control light and signal light are incident on the light absorption layer in the thermal lens forming element including at least the light absorption layer,
Two or more of the control lights are incident simultaneously,
In accordance with a desired optical path switching request, the presence or absence of irradiation and the irradiation intensity are determined for each of the two or more control lights,
The control light and the signal light are irradiated so as to converge at or near the light absorption layer, and the positions of the convergence points of the control light and the signal light are different in the direction perpendicular to the optical axis. Irradiated and
The wavelength of the control light is different from the wavelength of the signal light, the wavelength of the control light is selected from a wavelength band that is absorbed by the light absorption layer, and the wavelength of the signal light is from a wavelength band that is not absorbed by the light absorption layer. Chosen,
The control light and the signal light are converged and incident on the light absorption layer or in the vicinity thereof, so that the presence or absence of each of the two or more control lights in the light absorption layer and each According to the irradiation intensity, the direction of the signal light is changed by the refractive index change caused by the temperature rise occurring in the area where the control light is absorbed and the surrounding area, that is, the thermal lens,
The signal light whose traveling direction is changed in accordance with the presence / absence of each of the two or more control lights and the intensity of each of the control lights is incident on a specific light receiving means determined according to the desired optical path switching request. A vector-controlled optical path switching method.   The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed after being irradiated with the control light have an apparent convergence point in or near the light absorption layer. The vector-controlled optical path switching method according to claim 1, wherein the vector-controlled optical path switching methods are separated from each other.   The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed while being irradiated with the control light are converged or condensed by the same optical means, respectively, and the desired optical path 3. The vector-controlled optical path switching method according to claim 1, wherein the light is received by a specific light receiving means determined in response to the switching request.   The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed while being irradiated with the control light are converged or condensed by the same optical means, respectively, and the desired optical path 4. The vector-controlled optical path switching according to claim 1, wherein the light is received by an optical fiber provided as a specific light receiving means determined according to the switching request. 5. Method. Apparent convergence point of the signal light incident on the optical fiber, which is not irradiated with control light and whose signal direction is not changed, and one or more signal lights whose optical paths are switched in or near the light absorption layer distance, according to the optical fiber distance as the light receiving means 請 Motomeko 4 you, characterized in that the signal light is a distance obtained by dividing the imaging magnification of the optical means for converging or focusing light to the optical fiber vector Controlled optical path switching method. A signal light source that emits signal light of one or more wavelengths;
Two or more control light sources that simultaneously emit control light having a wavelength different from that of the signal light,
A control light source that is irradiated with the presence or absence of irradiation and the irradiation intensity determined for each of the two or more control lights according to a desired optical path switching request;
A thermal lens forming element including a light absorbing layer that transmits the signal light and selectively absorbs the control light;
Condensing means for condensing the control light and the signal light in the light absorbing layer or in the vicinity thereof by converging each of the convergence points in a direction perpendicular to the optical axis,
The thermal lens forming element is configured such that the two or more control lights and the signal light are converged and incident on the light absorption layer or in the vicinity thereof, whereby the two or more control lights in the light absorption layer are incident. Depending on the presence / absence of each light irradiation and the intensity of each light irradiation, the signal light travel direction is changed by a refractive index change caused by a temperature rise that occurs in the region that absorbs the control light and its surrounding region, that is, a thermal lens. ,
A vector-controlled optical path switching device comprising light receiving means for selectively receiving the signal light in response to the desired optical path switching request.   The thermal lens formed in the light absorbing layer of the thermal lens forming element is composed of a signal light whose traveling direction is not changed without being irradiated with the control light and a signal light whose traveling direction is changed after being irradiated with the control light. 7. The vector-controlled optical path switching device according to claim 6, wherein apparent convergence points at or near the light absorption layer are separated from each other.   The signal light whose traveling direction is not changed without being irradiated with the control light and the signal light whose traveling direction is changed while being irradiated with the control light are converged or condensed by the same optical means, respectively, and the desired optical path 8. The vector-controlled optical path switching device according to claim 6, wherein the light is received by a specific light receiving means determined in response to the switching request.   9. The vector-controlled optical path switching device according to claim 6, wherein the light receiving means is an optical fiber. The apparent convergence point distance of the signal light incident on the optical fiber whose signal direction is not changed and one or more signal lights whose optical paths are switched in the light absorbing layer or in the vicinity thereof is the distance between the light receiving optical fibers. vector controlled optical path switching apparatus as claimed in 請 Motomeko 9 you being a distance divided by the imaging magnification of the optical means for converging or condensing the signal light to the optical fibers.

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