JP4724817B2 - Chromatic aberration correction method and optical apparatus capable of correcting chromatic aberration - Google Patents

Description

  The present invention relates to a chromatic aberration correction method and an optical apparatus with corrected chromatic aberration, which are useful in the fields of optical electronics and photonics such as optical communication and optical information processing. More particularly, the present invention relates to a thermal lens type optical path deflection method and apparatus for deflecting light based on a change in refractive index due to a thermal lens effect, and an optical apparatus capable of correcting chromatic aberration.

  All-optical thermal lens forming optical element and light control method that directly modulates the intensity and frequency of light with light using the change in transmittance and refractive index caused by irradiating light to the thermal lens forming optical element There has been a great deal of research. The present inventors have used an organic nanoparticle photothermal lens forming element (see Non-Patent Document 1) in which an organic dye aggregate is dispersed in a polymer matrix with the aim of developing a new information processing technique using an all-optical type optical element. I have studied light control systems. 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. Forming the thermal lens by irradiating control light to a thermal lens forming optical element made of a photoresponsive composition and reversibly changing the transmittance and / or refractive index of signal light in a wavelength band different from the control light An optical control method for performing intensity modulation and / or light flux density modulation of the signal light transmitted through an optical element, wherein the control light and the signal light are converged and irradiated to the thermal lens forming optical element, and Adjusting the optical paths of the control light and the signal light so that regions having the highest photon density in the vicinity (beam waist) of the respective focal points of the control light and the signal light overlap each other in the thermal lens forming optical element. A light control method is disclosed (see Patent Document 1 to Patent Document 7). The thermal lens forming optical element made of a 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 signal light that reversibly forms a thermal lens based on a density change distribution caused by a temperature rise generated in a region where the photoresponsive composition absorbs the control light and a peripheral region thereof, and transmits 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 optical element, and the response time of the signal light with respect to the control light irradiation at the control light power of 2 to 25 mW is described as less than 2 microseconds. (See Patent Document 8). These methods are excellent in controlling light with light and can respond at high speed. However, there is a problem in that the shape of the light beam formed at the time of control light irradiation becomes a donut shape, so that the coupling efficiency to the optical fiber is small. .

  As a method for solving the above problem, the present inventors irradiate the light absorbing layer in the thermal lens forming optical element including the light absorbing layer with the control light and the signal light so as to converge on the light absorbing layer. And 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. Refracted by a thermal lens that is reversibly formed by converging and then diffusing on the light 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. A method of changing (deflecting) the traveling direction of the signal light by changing the rate (Japanese Patent Application No. 2006-46027), the signal light that is not irradiated with the control light and the traveling direction is not changed, and the control light is irradiated The direction of travel is And the obtained (deflected) signal light, and filed an optical path switching method characterized by separately detected (Japanese Patent Application No. 2006-46028 and Japanese Patent Application No. 2006-46029). This method eliminates the problem that the light beam shape of the signal light whose direction of travel has been changed (deflected) is not a donut shape and is close to the original light beam shape, so that the coupling efficiency to the optical fiber is small. Japanese Patent Application Nos. 2006-46027, 2006-46028, and 2006-46029 disclose a method of arranging a plurality of optical fibers close to one ferrule as an incident method of signal light and control light. ing. However, when the lens to be used is not corrected for chromatic aberration, the wavelength of the signal light (for example, 1550 nm) and the wavelength of the control light (for example, 980 nm) are different, and thus the light collected on the light absorption layer in the thermal lens forming optical element is collected. There is a problem in that the light spot is different, the amount of deflection of the signal light cannot be increased, the shape of the deflected signal light becomes a shape causing coma aberration, and the coupling efficiency to the optical fiber used for detection deteriorates.

  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).

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

  In the present invention, when two or more lights having different wavelengths are emitted from the respective emission regions arranged on the same surface and converged using the aspheric single lens, the aspheric single lens is An object of the present invention is to form two or more lights having different wavelengths on the same plane without correcting chromatic aberration.

  The present invention also provides a thermal lens element caused by chromatic aberration when a plurality of light beams having different wavelengths emitted in the vicinity are condensed on the thermal lens forming element by using an inexpensive optical system in which the same chromatic aberration correction is not sufficient. The purpose of this is to correct the difference in the light condensing point, increase the deflection angle of the signal light by the control light, and maintain the energy distribution in the beam section in a Gaussian distribution state without deteriorating the beam shape of the deflected signal light And This makes it possible to deflect light without using complicated and expensive electric circuits and mechanically moving parts with a small and inexpensive optical system, and has extremely few failures and high durability, and polarization dependence. Optical deflection method, optical deflection apparatus, and extinction ratio are extremely low, the light intensity attenuation of signal light is small, the deflection angle can be adjusted greatly with a small control light power, the adjustment is easy and the operation is stable It is also possible to provide a compact optical path switching device and an optical path switching method capable of one input and multiple outputs.

  The present invention has the following features.

(1) Control light and signal light are incident on a light absorption layer in a thermal lens forming optical element including at least a light absorption layer, and the control light and the signal light converge at or near the light absorption layer. And 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, and the wavelength of the control light and the wavelength of the signal light are different from each other. The wavelength band of the signal light is selected from a wavelength band that is absorbed by the light absorption layer, the wavelength of the signal light is selected from a wavelength band that is not absorbed by the light absorption layer, and the control light and the signal light are the control light in the light absorption layer. In the light deflection method, wherein the refractive index is changed by the thermal lens formed reversibly due to the temperature rise occurring in the absorbed region and the surrounding region, and the traveling direction of the signal light is changed. The control light Preliminary the signal light, respectively is emitted from the emission region of each, which are arranged on the same plane, at least one of the control light and the signal light of the thickness t for each wavelength of light of the control light and the signal light passed through a stated optical plate corrected substantial optical path length, common to the control light and the signal light, the control light and the signal light is passed through an optical means for imaging on the same surface This is a chromatic aberration correction method for forming an image.

(2) A region that emits signal light, a region that is provided in the same plane as the signal light emission region, emits one or more types of control light having a wavelength different from that of the signal light, and emits the control light Provided adjacent to or in contact with each of the signal light output region and the signal light output region, and further provided at a position through which only the signal light passes, and opening from the incident side toward the output side according to the opening angle of the signal light. An optical flat plate having a thickness t so that the control light does not interfere with the signal light emitted while expanding through the hole, and the signal light is transmitted, A thermal lens forming optical element including a light absorbing layer that selectively absorbs control light; and a wavelength band that is emitted from the optical flat plate and absorbed by the light absorbing layer at or near the light absorbing layer of the thermal lens forming element. The system selected from Condensing means for condensing light and the signal light selected from the wavelength band that is emitted from the optical flat plate and is not absorbed by the light absorption layer so that the convergence points thereof are different from each other, and the heat The lens-forming optical element is refracted by a thermal lens that is reversibly formed due to a temperature rise in the area where the control light and the signal light have absorbed the control light in the light absorption layer and its peripheral area. And the optical flat plate and the condensing means transmit the signal light and at least one control light on the same plane of the thermal lens forming optical element. a color aberration correcting optics apparatus which Ru is imaged.

  (3) In the chromatic aberration correction method of (1), the thickness t of the optical flat plate is expressed by the following formula [1].

t ≦ (dc) / 2N (1)
(Here, c is an average diameter when the emission area is approximated to a circle, d is an average distance between the emission areas approximating a circle, and N is a numerical aperture of light emitted from the emission area.)

  (4) In the optical device in which the chromatic aberration of (2) is corrected, the thickness t of the optical flat plate is expressed by the following formula [1].

t ≦ (dc) / 2N (1)
(Here, c is an average diameter when the emission area is approximated to a circle, d is an average distance between the emission areas approximating a circle, and N is a numerical aperture of light emitted from the emission area.)

(5) The chromatic aberration correction method according to (1) or (3), wherein the signal light, the signal light, and at least one control light having different wavelengths are respectively emitted on the same plane. The emission region is a core of a plurality of optical fibers having a core / cladding structure in which end faces are arranged on the same surface and bundled.

(6) The optical device capable of correcting chromatic aberration according to (2) or (4), wherein signal light and at least one control light having different wavelengths are emitted on the same plane. The arranged emission regions are cores of a plurality of optical fibers having a core / cladding structure in which each end face is arranged on the same surface and bundled.

  According to the present invention, when two or more lights having different wavelengths are emitted from the respective emission regions arranged on the same plane and converged using the aspheric single lens, the aspheric single unit is used. Even if the lens does not correct chromatic aberration, it is possible to form an image of two or more lights having different at least one wavelength on the same plane.

  According to the present invention, when a plurality of signal light and control light having different wavelengths are emitted from the respective emission regions arranged on the same plane and converged using an aspherical single lens, the aspherical surface Even if a single lens is not corrected for chromatic aberration, it can be focused and irradiated on the same plane, and the change in refractive index caused by control light irradiation can be efficiently applied to the signal light. It is possible to deflect with low power without deteriorating the shape of the signal light. Further, the optical path can be switched using the deflection of the signal light. Furthermore, the deflected signal light is output from the thermal lens forming optical element in the same shape as the beam cross-section before condensing, and can be taken out by entering the optical fiber arranged in a minute form, so it is compact and can be used in multiple directions. An optical switch that switches the optical path is possible. In addition, since a low-power semiconductor laser can be used, a small and inexpensive device can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, “chromatic aberration” refers to a difference in image point position on the optical axis from one color to another, and axial chromatic aberration.

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

  FIG. 3 a schematically shows an emission side end face of the seven-core optical fiber 120 of the seven-core optical fiber 120.

  Further, FIG. 5 schematically shows the spread of the signal light 1 and the control light 21 emitted from the light emission side end face of the seven-core optical fiber 120.

  In FIGS. 1, 3a, and 5, two or more single mode optical fibers are bundled as light sources that emit two or more lights having different wavelengths from the respective emission regions arranged on the same plane. Using the 7-core optical fiber 120 in which the light exit end face of each optical fiber is polished to be in the same plane, the core of each optical fiber is the exit area, and the exit end face 101 of the core 100 of the optical fiber at the center of the 7-core optical fiber 120 is used. The signal light 1 is emitted, the control light 21 is emitted from the exit end face of the optical fiber core 201 around the seven-core optical fiber 120, the signal light 1 and the control light 21 have different wavelengths, and the signal light 1 is the signal light and the control light. So as to pass through the hole 3 provided in the optical flat plate 4 for correcting the shift of the condensing point, that is, the chromatic aberration due to the difference in wavelength of The control light 21 is transmitted through the optical flat plate 4 arranged in contact with the emission end face of the seven-core optical fiber 120 so as to avoid the hole 3, and the signal light 1 and the control light 21 are common for image formation. The light passes through the condenser lenses 5 and 6 as optical means and forms an image on the light absorbing layer 71 of the thermal lens forming element 7 or on the same plane in the vicinity thereof. The light absorption layer 71 of the thermal lens forming element 7 does not absorb the wavelength of the signal light 1 and has a light absorption spectrum characteristic that absorbs the wavelength of the control light 21. When the control light 21 is not irradiated, the signal light 1 travels straight through the thermal lens forming element 7. When the control light 21 is irradiated, the light absorbing layer 71 of the thermal lens forming element 7 absorbs the control light 21 and its region. The optical path of the signal light 1 is deflected by the refractive index change accompanying the temperature rise that occurs in the peripheral area, that is, the refractive index distribution in which the refractive index decreases as the temperature increases (this is called the thermal lens effect). The signal light 2 is emitted.

  As the seven-core optical fiber 120, 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, inserted into the hole of the ferrule 121, and fixed with an adhesive 122, For example, the central core 100 and the peripheral cores 201, 202, 203, 204, 205, and 206 have a diameter of 9.5 μm and a central cladding. 110 and peripheral claddings 211, 212, 213, 214, 215, and 216 all had a diameter of 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.

  The seven single-mode optical fibers constituting the seven-core optical fiber 120 were used by etching a clad layer of a single-mode quartz optical fiber having a core diameter of 9.5 μm 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 71. 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 six peripheral optical fibers are connected to six light sources (not shown) of the control lights 21 to 26, respectively.

  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.

  As the light source of the control lights 21 to 26, for example, a maximum of six semiconductor lasers having an oscillation wavelength of 980 nm and an output of 10 to 20 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.

  There are no particular restrictions on the wavelengths and outputs of the signal light and control light, and any of those available according to the application can be selected and used.

  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 71 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.

  When the control light is absorbed by the light absorption layer of the thermal lens forming optical element 7, 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. Further, since the light is condensed and incident, the change in the refractive index in the vicinity of the condensing point is large. Since the signal light is incident close to the control light, the signal light is deflected due to the change in the refractive index caused by the control light (the traveling direction is bent). The deflection angle changes almost in proportion to the intensity of the control light.

  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 has not yet been collected in the vicinity of the condensing point of the control light, and the influence of the refractive index on the signal light is light. Depending on the cross-sectional position perpendicular to the axis, 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 21 is transmitted through the optical flat plate 4 arranged in contact with the emission 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 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, in the tapered hole 3, the hole 30 adjacent to the emission side end face of the seven-core optical fiber 120 is small, and the emission side hole 31 of the optical flat plate 4 is large. 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 30 is preferably 10 to 20 μm, and the diameter of the hole 31 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. 5, 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 21 passes through the optical plate 4 having a higher refractive index than the core material from the end surface 2011 of the core 201 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.

  Also for the control lights 22 to 26, the chromatic aberration is corrected in the same manner as the control light 21.

(Second Embodiment)
FIG. 2 is a schematic configuration diagram of an optical deflection type optical path switching device according to a 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. In FIG. 2, the difference from the first embodiment is that the signal light that has passed through the thermal lens element 7 is received by the condenser lenses 8 and 9, collimated, and then incident on the light receiving side optical fiber 130. is there. Other configurations are the same as those of the first embodiment. The lens 8 was an aspheric lens having a focal length of 2 mm, and the lens 9 was an aspheric lens 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.

  3A is a cross-sectional view taken along the line A-A ′ in FIG. 2, and schematically shows the light emission side end face of the seven-core optical fiber 120.

  FIG. 3B is a cross-sectional view taken along line B-B ″ in FIG. 2, and schematically shows the light receiving side end face of the seven-core optical fiber 130.

  When the signal light 1 is emitted from the central core 100 of the seven-core optical fiber 120 and the control lights 21 to 26 are not irradiated, the signal light 1 is collected by the condenser lenses 5 and 6, the thermal lens forming element 7, and the condenser lenses 8 and 9. And enter the central core 300 of the seven-core optical fiber 130. Such incident on an arbitrary core of the seven-core optical fiber 130 can be detected by providing a photodetector at each of the emission-side ends (not shown; independently present) of the seven-core optical fiber 130. It goes without saying that the photodetector may be installed directly without using the seven-core optical fiber 130.

  The adjustment of the selective incidence of the light receiving side optical fiber 130 on the cores 300 to 306 is performed by first adjusting the position of the core 300 that detects the straight signal light 1, and then adjusting the control light power of the control lights 21 and 22, for example. The incident efficiency to the core 301 was improved. If there is a shift in the rotation direction around the center of the central cores 100 and 300 on the light emitting side and the light receiving side of the seven-core optical fiber, if only one control light is incident, the light enters the light receiving side core. Can not be enough. The deviation in the direction perpendicular to the optical axis can be adjusted by changing the intensity of the control light, but the rotation direction cannot be adjusted. Therefore, adjustment of incidence on the light receiving side core was performed as follows.

  1. First, the vertical and horizontal positions of the light-irradiating side seven-core optical fiber 120 and the light-receiving side seven-core optical fiber and the positions in the rotation direction around the centers of the central cores 100 and 300 are roughly matched.

  2. Next, the light receiving side 7-core optical fiber is completely irradiated with the central core 300 of the light receiving side 7-core optical fiber 130 without irradiating the control light so that the straight signal light 1 emitted from the center core 100 of the emission side 7-core optical fiber 120 can be completely received. Move the position of 130 in the direction of the three axes to make fine adjustments.

  3. Next, the control light 21 is emitted from one of the peripheral cores of the emission-side 7-core optical fiber 120, for example, the core 201, and the optical path of the signal light 1 emitted from the central core 100 of the emission-side 7-core optical fiber 120 is deflected. The seven-core optical fiber 130 is rotated with the central axis of the central core 300 as the center of rotation, and the deflected signal light 221 is precisely received by one of the peripheral cores of the light-receiving-side seven-core optical fiber 130, for example, the core 301. Adjust to. Next, the control light 21 is turned off, the control light 22 is emitted from the peripheral core 202 of the emission-side seven-core optical fiber 120, and the light intensity is finely adjusted, whereby the deflected signal light 222 is received by the reception-side seven-core optical fiber 130. The peripheral core 302 is adjusted so that it can receive light completely. If the signal light cannot be completely received by the core 302 only by the intensity of the control light 22 due to the processing accuracy of the seven-core optical fibers 120 and 130, the peripheral core adjacent to the core 202 from which the control light 22 is emitted The control light 21 or 23 is also emitted from the 201 or 203 (with a lower intensity than the control light 22), and fine adjustment is performed so that the core 302 can receive the signal light completely. In the same manner, adjustment is performed so that the signal light can be completely received by the peripheral cores 303 to 306 of the light receiving side seven-core optical fiber 130 by irradiation of the control lights 23 to 26 in the same manner.

  As described above, as described in the present embodiment, the signal light 1 has the holes 3 provided in the optical flat plate 4 for correcting the shift of the focal point due to the difference in wavelength between the signal light and the control light, that is, chromatic aberration. The control lights 21 to 26 pass through the optical flat plate 4 arranged in contact with the emission end face of the seven-core optical fiber 120 so as to avoid the hole 3, so that the output-side seven-core optical fiber 120 is transmitted. The optical path of the signal light 1 emitted from the central core 100 can be deflected and adjusted so that it can be completely received by the peripheral cores 303 to 306 of the light receiving side seven-core optical fiber 130.

  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. It is a schematic block diagram of the light deflection type optical path switching device concerning a 2nd embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line A-A ′ of FIG. 2, and schematically shows a light emission side end surface of a seven-core optical fiber 120. FIG. 3 is a cross-sectional view taken along line B-B ′ in FIG. 2, 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. FIG. 5 is a cross-sectional view taken along line C-C ′ in FIG. 4, schematically illustrating the spread of the signal light 1 and the control light 21 emitted from the light emission side end face of the seven-core optical fiber 120.

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 condenser lens, 21, 22, 23, 24, 25, 26 control light emitted from the peripheral cores 201, 202, 203, 204, 205 and 206 of the 7-core optical fiber 120, 30 Tapered hole (small), 31 Tapered hole (large), 71 Light absorption layer, 100 7-core optical fiber 120 central core, 101 Core 100 emission end face, 110 7-core optical fiber 120 central cladding, 120 Light emission Side 7-core optical fiber, 121 7-core optical fiber 120 ferrule, 122 adhesive, 130 light-receiving side 7-core optical fiber 131, ferrule of 7-core optical fiber 130, 132 adhesive, 201, 202, 203, 204, 205, 206 peripheral core of 7-core optical fiber 120, 211, 212, 213, 214, 215, 216 peripheral cladding of 7-core optical fiber 120 , 221, 222 Signal light deflected in the optical path by the thermal lens forming element 7, central core of 300 7-core optical fiber 130, peripheral core of 301, 302, 303, 304, 305, 306 peripheral core of 7-core optical fiber 130, 310 7-core optical fiber 130 Center cladding, 311, 312, 313, 314, 315, 316 peripheral cladding of the seven-core optical fiber 130, 1001 light traveling direction, output end surface of the peripheral cladding 201 of the seven-core optical fiber 120, 2112 control from the optical flat plate 4 Emitting surface of the light 21.

Claims (6)

The control light and the signal light are incident on the light absorption layer in the thermal lens forming optical element including at least the light absorption layer,
The control light and the signal light are irradiated so as to converge at or near the light absorption layer, and 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,
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 have a refractive index changed by a heat lens formed reversibly due to a temperature rise occurring in a region where the control light is absorbed in the light absorption layer and a peripheral region thereof, In the light deflection method characterized by changing the traveling direction of the signal light,
Further, the control light and the signal light are respectively emitted from the respective emission regions disposed on the same plane, and at least one of the control light and the signal light is a wavelength of the light of the control light and the signal light The optical path length is corrected by passing an optical flat plate having a thickness t every time,
A chromatic aberration correction method, wherein the control light and the signal light are imaged on the same plane by passing through an optical means for image formation common to the control light and the signal light. An area for emitting signal light;
An area for emitting one or more types of control light having a wavelength different from that of the signal light, which is provided in the same plane as the emission area of the signal light;
Provided adjacent to or in contact with each of the region emitting the control light and the region emitting the signal light, and further provided at a position allowing only the signal light to pass through, and exiting from the incident side according to the opening angle of the signal light An optical flat plate having a tapered hole whose opening increases toward the side, and having a thickness t so that the control light and the signal light emitted while expanding through the hole do not interfere with each other;
A thermal lens forming optical element including a light absorbing layer that transmits the signal light and selectively absorbs the control light;
The control light selected from the wavelength band emitted from the optical flat plate and absorbed by the light absorbing layer on or near the light absorbing layer of the thermal lens forming element, and the light absorbing layer emitted from the optical flat plate Light collecting means for condensing the signal light selected from a wavelength band that does not absorb, so that the convergence points are different from each other,
Have
The thermal lens forming optical element is formed by a thermal lens that is reversibly formed due to a temperature rise that occurs in the area where the control light and the signal light absorb the control light in the light absorption layer and in the peripheral area. , The refractive index changes, changes the traveling direction of the signal light,
Further, the optical plate and the focusing means, the signal light and at least one of said control light, possible chromatic aberration correction, wherein the benzalkonium is focused on the same plane of the heat lens forming optical element Optical device. 2. The chromatic aberration correction method according to claim 1, wherein the thickness t of the optical flat plate is expressed by the following formula [1].
t ≦ (dc) / 2N (1)
(Here, c is an average diameter when the emission area is approximated to a circle, d is an average distance between the emission areas approximating a circle, and N is a numerical aperture of light emitted from the emission area.) The optical apparatus capable of correcting chromatic aberration according to claim 2, wherein the thickness t of the optical flat plate is expressed by the following equation [1].
t ≦ (dc) / 2N (1)
(Here, c is an average diameter when the emission area is approximated to a circle, d is an average distance between the emission areas approximating a circle, and N is a numerical aperture of light emitted from the emission area.)   A core / cladding system in which signal light, at least one control light having a different wavelength and each of the control light beams are emitted and arranged in the same plane, each end face being arranged on the same plane and bundled The chromatic aberration correction method according to claim 1, wherein the chromatic aberration correction method is a core of a plurality of optical fibers having a structure.   A core / cladding system in which signal light, at least one control light having a different wavelength and each of the control light beams are emitted and arranged in the same plane, each end face being arranged on the same plane and bundled 5. The optical device capable of correcting chromatic aberration according to claim 2, wherein the optical device is a core of a plurality of optical fibers having a structure.

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