JP3721040B2 - Fiber-type optical device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fiber-type optical element and a manufacturing method thereof, and in particular, has transparent electrodes on end faces and side faces of an optical fiber, and an electric field, voltage, and current are applied to or injected into a functional material by using the electrodes. The present invention relates to a fiber-type optical element that controls polarization and phase, or emits and receives light, and a manufacturing method thereof.
[0002]
[Prior art]
Conventionally, various optical elements using optical fibers, for example, elements for controlling light loss and polarization, have been reported and are commercially available. In most cases, the light from the optical fiber is collimated by a lens to fly into free space, transmitted through an element that has an electro-optic effect, light modulation effect, and filter effect, and then condensed by the lens to be coupled to the output optical fiber. There are many things to ring.
[0003]
For example, a variable optical attenuator and a variable wavelength filter of a type in which an ND filter or a wavelength filter is inserted between two opposing collimators and the position is moved or rotated have been developed. Alternatively, a variable optical attenuator and variable wavelength filter have been developed to control the loss of light by sandwiching a liquid crystal layer sandwiched between two glass plates with transparent electrodes between opposing collimated fibers. Control elements are also commercially available.
[0004]
[Problems to be solved by the invention]
However, since these elements use a collimator, they require labor for alignment of optical fibers, become large, and have a problem that it is difficult to form an array.
[0005]
In addition, in order to couple light from a semiconductor laser or light emitting diode to an optical fiber, or to couple light from an optical fiber to a detector, these elements are mounted on a mount and a lens is arranged. Need to be aligned and labor is required.
[0006]
In an element in which light passes through a transparent electrode, indium tin oxide (hereinafter simply referred to as ITO), which is a transparent electrode, is usually formed on a glass substrate. The transparent electrode ITO has a high transmittance in visible light, but the transmittance decreases as the wavelength becomes longer. In the near-infrared wavelength band 1.55 μm which is a communication wavelength band, due to the influence of the plasma absorption edge by the carrier, There was a problem that the transmittance decreased to 50% even at a film thickness of 40 nm.
[0007]
In₂O_Three, SnO₂There were similar problems with transparent electrodes such as ZnO. Further, when these transparent electrodes are formed on an optical fiber, it is difficult to form a transparent electrode having a high transmittance on the end face of the optical fiber because the heat resistance of the coating of the optical fiber is low.
[0008]
An object of the present invention is to provide an optical element (device) that can be easily aligned and can be miniaturized and arrayed, and a manufacturing method thereof.
[0009]
  Another object of the present invention is to provide an optical fiber in which a transparent electrode is formed on the end face and side face of an optical fiber, and a light emitting element and a light receiving element are provided on the end face.formAn object is to provide an element and a manufacturing method thereof.
[0010]
Another object of the present invention is to provide an optical fiber type element using a transparent electrode having a high transmittance in the visible light / near infrared wavelength band formed on the end face and side face of an optical fiber, and a manufacturing method thereof.
[0011]
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.
[0012]
[Means for Solving the Problems]
The outline of the invention disclosed in the present application will be briefly described as follows.
[0013]
  (1) In the fiber type optical element, the fiber coating has a heat resistance of 100 ° C. or more, and is composed of an optical fiber provided with transparent electrodes on the end surface and side surfaces, and the coating of the fiber is metal or polyimide, The transparent electrode is, Indium tin oxide (ITO), In ₂ O ₃ , SnO ₂ , ZnO, and100 ° C or higher400 ℃ or lessFormed withThe
[0014]
(2) In the fiber-type optical element of the means (1), a pair of optical fibers provided with the transparent electrode on the end surface and side surfaces are opposed to each other with a gap between the end surfaces, and the optical axes of both coincide with each other. The gap between the end faces of the optical fiber is filled or inserted with a material / element having an electro-optic effect or a light modulation effect, and the intensity or polarization of the light is controlled or the wavelength is selected. To do.
[0015]
(3) In the fiber-type optical element of the means (1), the one optical fiber is fixed to a substrate, a groove perpendicular to the optical fiber is provided, a transparent electrode is provided on a wall surface of the groove, and the groove A material / element having an electro-optic effect / light modulation effect is filled in or inserted, and the intensity and polarization of the light are controlled and the wavelength is selected.
[0016]
(4) In the fiber type optical element of the means (2) or (3), the material having the electro-optic effect and the light modulation effect is a nematic liquid crystal, a polymer dispersed liquid crystal, a polymer network liquid crystal, a ferroelectric liquid crystal, One of a cholesteric-nematic phase transition liquid crystal, a dynamic scattering liquid crystal, or an electrochromic material, and the element having the electro-optic effect and the light modulation effect is a semiconductor surface light modulator or an electro-optic crystal surface light. It is a modulator.
[0017]
(5) The fiber type optical element of the means (1) includes any one of an electroluminescence element, a surface emitting laser, and a surface detector on the transparent electrode on the end face of the optical fiber.
[0018]
(6) In the fiber-type optical element of the means (5), the electroluminescent element includes organic thin film electroluminescence, inorganic thin film electroluminescence doped with a luminescent element in ZnS, ZnSe, and ZnS phosphor mixed in a binder. The organic dispersion type electroluminescence and the electroluminescence mainly composed of any one of the ultrafine particle Si films.
[0021]
  (7) The fiber coating has a heat resistance of 100 ° C. or more, and is composed of an optical fiber having transparent electrodes provided on the end surface and side surfaces, and the fiber coating is a method for producing a fiber type optical element made of metal or polyimide. , Indium tin oxide (ITO), In on the end face and side face of the optical fiber₂O_Three, SnO₂In addition, a transparent electrode is formed by sputtering or vapor-depositing any one material of ZnO, and the transparent electrode is at least 100 ° C.400 ℃ or lessFormed with.
[0022]
  (8) Said means (7), The pair of optical fibers having the transparent electrode formed on the end face and the side face are opposed to each other with a gap between the end faces, and the optical axes of the two are aligned. In this method, the gap between the end faces of the optical fiber is filled or inserted with a material / element having an electro-optic effect or a light modulation effect.
[0023]
  (9) Said means (8), A jig for arranging the optical fibers to face each other and aligning the optical axes is an optical connector comprising a V-groove, an optical fiber connecting splice, a ferrule, and a sleeve. Consists of any one of the cabbages.
[0026]
That is, the point of the present invention is that it is usually used as an optical fiber connector in order to form transparent electrodes on the end face and side face of the optical fiber so that the optical fiber can be easily aligned and arrayed. The optical fiber bonding splice, V-groove array, microcavity, optical connector and the like are used. Further, the optical fiber is fixed in the groove, a groove is provided perpendicularly to the groove, and a transparent electrode is formed on the wall surface of the groove so that alignment is unnecessary.
[0027]
Furthermore, as a light source / light receiving element for optical fibers, a configuration and a manufacturing method were developed in which the transparent electrode was formed and a layer or element that emits light by voltage, electric field, or current or a layer or element that receives light was formed and installed. Realized a method that is small, easy to array, and easy to align.
[0028]
The present invention can be applied not only to glass fibers but also to plastic fibers as optical fibers.
[0029]
Furthermore, it has been found that the formation temperature of a transparent electrode having a high transmittance is 100 ° C. to 400 ° C. In particular, in the case of ITO, it has been found that when the temperature at which ITO is formed and the heat treatment temperature are increased from 100 ° C. to 400 ° C., the transmittance increases. Furthermore, it has been found that when the substrate temperature is set to 100 ° C. and the heat treatment temperature is set to 300 ° C. to 350 ° C., the transmittance in the visible to near-infrared wavelength band is improved to nearly 100%. The transmittance in the communication wavelength band of 20 nm thick ITO produced by this method is 99% or more.
[0030]
The transparent electrode is not limited to ITO, and the conventionally known In₂0_Three, SnO₂It has been found that the substrate temperature and the heat treatment temperature are optimally 100 to 400 ° C. even for transparent electrodes such as ZnO. Furthermore, when a transparent electrode is formed under the above conditions on a normal optical fiber or an optical fiber inserted into a ferrule, the normal coating layer (protective film) is a UV coating with low heat resistance, and the ferrule and optical fiber adhesive Since the heat resistance is low, the UV coat and adhesive are burnt and blackened. In the present invention, it has been found that a metal coat or a polyimide coat is optimal as a coating material in place of the conventional UV coated fiber having a heat resistance of 100 ° C. or less.
[0031]
The present invention is not limited to the above, and can be applied to all fiber type optical elements in which transparent electrodes are formed on the end face and side face of the optical fiber.
[0032]
Hereinafter, the present invention will be described in detail with reference to the drawings together with embodiments (examples) according to the present invention.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
    Example 1
  FIG. 1 shows an optical attenuator (fiber) according to a first embodiment of the present invention.formFIG. 2 and FIG. 3 are schematic views of the optical attenuator (fiber) shown in FIG.formIt is a figure for demonstrating the preparation methods of an optical element. 1 to 3, 1-1 is an optical fiber core (for example, using glass fiber), 1-2 is an optical fiber coated with a protective film, 1-2A is a protective film made of metal or polyimide (coated) Layer) 1-3 is an ITO transparent electrode formed on the fiber end face and side face, 1-4 is a glass splice holder, 1-5 is a micro glass cavity having a V-groove 1-5A, 1-6 is a splice lid, 1-7 is a metal plate for holding the fiber, and 1-8 is a material having the electro-optic effect or the light modulation effect (for example, polymer network liquid crystal, polymer dispersed liquid crystal, cholesteric-nematic liquid crystal, etc.), 1- 9 is an extraction electrode, and 1-10 is an insulating film.
[0034]
  Example 1 Optical attenuator (fiberformAs shown in FIGS. 1 to 3, for example, the optical element 1 is an optical fiber 1 coated with an optical fiber core wire 1-1 made of glass fiber and a protective film (coating layer) 1-2A made of metal or polyimide. -2, ITO transparent electrode 1-3 formed on the end face and side face of optical fiber 1-2, glass splice holder 1-4, micro glass cavities 1-5 having V groove 1-5A, glass splice holder 1-4 1-6, metal plate 1-7 for holding fiber, material having electro-optic effect or light modulation effect (for example, using polymer network liquid crystal, polymer dispersed liquid crystal, cholesteric-nematic liquid crystal, etc.) 1-8 And an extraction electrode 1-9 and an insulating film 1-10.
[0035]
  Example 1 Optical attenuator (fiberformAs shown in FIG. 2, first, as shown in FIG. 2 (a), the optical device is manufactured around the optical fiber 1-1, for example, a protective film (covering layer) 1-2A made of polyimide. An optical fiber 1-2 coated with is prepared. Alternatively, an optical fiber in which a metal is coated on the optical fiber core 1-1 may be used. These optical fibers 1-2 have been developed as submarine optical fibers in order to improve reliability, and are easily available.
[0036]
When a bare optical fiber without a protective film (coating layer) 1-2A is used, the side of the optical fiber is scratched and cheap, and the ITO transparent electrode can be formed at temperatures up to 400 ° C. It is difficult to manufacture, and a heat-resistant protective film (coating layer) 1-2 is required for the optical fiber as in the present invention.
[0037]
Next, as shown in FIG. 2B, the polyimide coat (protective film) 1-2A of the optical fiber 1-2 is peeled off with a fiber stripper so that the optical fiber core 1-1 protrudes about several centimeters. At this time, if the stripper temperature is kept high at 700 ° C., the polyimide coat (protective film) 1-2A is easily peeled off. Alternatively, the protective film (coating layer) 1-2 can be peeled off by immersing in sulfuric acid heated to about 100 ° C. In the case of a metal coated fiber, the metal protective film (coating layer) 1-2A can be removed by dipping in an acid such as hydrochloric acid or sulfuric acid.
[0038]
As shown in FIG.2 (b), it cut | disconnects so that the end surface of the optical fiber 1-2 may become flat with a fiber cutter. Desirably, the end face of the optical fiber 1-2 is polished to further improve the characteristics.
[0039]
In this state, it is put into an ITO vapor deposition apparatus or a sputtering apparatus. Next, as shown in FIG. 2C, the optical fiber 1-2 is formed by sputtering or vapor-deposited so that the ITO transparent electrode 1-3 is formed on the end face and the side face. In the case of sputtering, the ITO transparent electrode 1-3 is formed on the entire end face and side face. On the other hand, in the case of vapor deposition, the ITO transparent electrode 1-3 is formed on part of the end face and side face. Since the heat-resistant temperature of polyimide is 400 ° C. and the temperature of metal is higher, the substrate temperature is set to 100 ° C., ITO is formed by sputtering at about 40 nm, and the temperature of the optical fiber 1-2 is set in an oxygen atmosphere to increase the transmittance. Annealing is performed at 350 ° C. for 2 hours and a half.
[0040]
FIG. 4 shows that the transmittance of the transparent electrode in the communication wavelength band is increased by annealing in this way. 4A shows a transmission spectrum before annealing, and FIG. 4B shows a transmission spectrum of 40 nm ITO annealed at 350 ° C. for 150 minutes. It can be seen that the loss of 1.0 dB is improved to a loss of about 0.2 dB at a communication wavelength of 1.55 μm (this spectrum includes reflection loss, and the maximum transmittance in the visible region is almost the same except for the reflection loss). 100% transmittance). Similar effects were obtained at a substrate temperature of 100 ° C. to 300 ° C. and an annealing temperature of 200 ° C. to 400 ° C. Further, the ratio of Sn to In is preferably 0 to 10 wt%.
[0041]
Further, the transparent electrode 1-3 is not limited to ITO, but is conventionally known In₂0_Three, SnO₂Even for transparent electrodes such as ZnO, the substrate temperature and the heat treatment temperature were optimally 100 to 400 ° C.
[0042]
Next, as shown in FIG.2 (d), the optical fiber splice holder 1-4 generally marketed as an optical fiber connector is prepared. Here, four cores are shown, but one, four, eight, and twelve cores are commercially available. The optical fiber is inserted into the V groove 1-5A and the microcavity 1-5 from both sides. Normally, matching oil is applied to a portion where the optical fiber faces, but an optical fiber splice holder (for example, a glass splice holder) 1-4 from which the matching oil is removed is used.
[0043]
As shown in FIG. 3A, the optical fiber 1-2 is inserted from the left and right sides of the microcavity 1-5, and the length of the gap 1-8A is adjusted while observing with a microscope. The gap 1-8A of the optical fiber 1-2 is filled with the material 1-8 having the electro-optic effect or the light modulation effect. As the material 1-8, for example, polymer-dispersed liquid crystal, polymer network-type liquid crystal, cholesteric-nematic phase transition liquid crystal, dynamic scattering liquid crystal, or the like is used. At this time, if an alignment film is required, the optical fiber is dipped in the alignment film and dried in advance. Usually, in the case of the liquid crystal, an alignment film is not necessary.
[0044]
In the case of a polymer dispersion type or polymer network type liquid crystal, it is solidified by irradiation with ultraviolet rays UV.
[0045]
Next, as shown in FIG. 3B, a takeout electrode 1-9 for taking out the electrode is taken out from the ITO transparent electrode 1-3 on the side surface of the optical fiber 1-2 using an adhesive and a conductive paste.
[0046]
Further, as shown in FIG. 3C, in order to accurately align the optical fiber 1-2, the opening of the glass splice holder 1-4 is covered with a lid 1-6, and the optical fiber 1-2 is Hold with metal crimping plate 1-7 and press down. At this time, when a metal plate is used as the pressing lid 1-6, the thin insulating film 1-10 is bitten as a spacer so that the ITO transparent electrode 1-3 of the optical fiber 1-2 facing the short circuit is not short-circuited. .
[0047]
FIG. 5 shows the characteristics of the optical attenuator manufactured by the above process. The gap of the optical fiber is about 10 μm, and the filled liquid crystal is a polymer network liquid crystal. It operates at a very low voltage of about 1.5 V, power consumption is μW, loss can be controlled from about 10 dB to about 0.2 dB, and there is no polarization dependence. Furthermore, arraying up to 12 cores was very easy, and a small, multi-fiber optical attenuator could be realized.
[0048]
In the manufacturing process, the optical fiber 1-2 was aligned using the glass splice holder (optical fiber splice holder) 1-4. However, the optical fiber 1-2 was placed on the V-groove array of Si, glass, and plastic. The alignment may be performed, or the glass microferrule may be taken out from the glass splice holder 1-4 to perform alignment. Alternatively, the optical fiber 1-2 may be inserted into the ferrule, and the optical fiber 1-2 may be inserted from the left and right sides of the optical connector sleeve for alignment.
[0049]
When cholesteric-nematic phase transition liquid crystal, polymer dispersed liquid crystal, and dynamic scattering liquid crystal were used, the driving voltage was as high as about 10 V, but similar optical attenuator characteristics were obtained.
[0050]
In the above, the liquid crystal material is filled in the groove, but the same effect was obtained with the electrochromic material. Furthermore, III-V semiconductor surface modulators such as InP and GaAs or LiNbO_ThreeThe modulator is inserted so that the transparent electrode formed on the end surface of the optical fiber 1-2 and the electrode on the back surface of the surface modulator are in contact with each other. The light could be modulated and attenuated in the same manner even when the optical fiber 1-2 was sandwiched.
[0051]
(Example 2)
In the first embodiment, a method of manufacturing an optical attenuator that controls the loss of light has been described. In the second embodiment, an optical polarization control element that converts an arbitrary polarization into a polarization in a specific direction will be described. .
[0052]
  Example 2 Optical Polarization Control Element (Fiber) of Example 2formThe manufacturing process of the optical element is shown in FIGS. 6 and 7, 4-1 is a polyimide alignment film, 4-2 is a rubbing roll, 4-3 is a marker indicating a rubbing direction, and 4-4 is a nematic liquid crystal.
[0053]
The same steps as those in FIG. 1 are performed until preparation of the optical fiber, end face cutting, and ITO deposition. The transparent electrode is not limited to ITO, and the conventionally known In₂O_Three, SnO₂A transparent electrode such as ZnO may be used.
[0054]
As shown in FIG. 6A, the optical fiber 1-2 is immersed in a polyimide alignment film solution, dried and cured to form a polyimide alignment film 4-1. Next, as shown in FIG. 6B, the rubbing machine 4-2 is rubbed by adjusting with a fine moving base so that the roll of the optical fiber 1-2 is in contact with the roll. At this time, the rubbing direction of the end face of the optical fiber 1-2 is entered with the marker 4-3 on the side face of the optical fiber.
[0055]
Next, as shown in FIG. 6 (c), the rubbed optical fiber is inserted into a fiber splice (glass splice holder 1-4) in an antiparallel or 90 degree orientation when facing each other and the same as in the first embodiment. Fix it. Next, as shown in the left diagram of FIG. 7A, the liquid crystal is a nematic liquid crystal. When the optical fibers are opposed in antiparallel, a parallel alignment cell is formed, and in the case of 90 degrees, twisted nematic alignment is formed. Is done.
[0056]
When the voltage is turned on, it is oriented parallel to the optical axis as shown in the right figure of FIG. That is, in the case of a parallel alignment cell, it operates as a variable wave plate, and in the case of a twisted nematic liquid crystal, it operates as an optical rotator that rotates the polarization by 90 degrees.
[0057]
As shown in FIG. 7B, when the parallel alignment elements are tilted 45 degrees from each other and the two elements are connected, an arbitrary elliptically polarized wave can be converted into a linearly polarized wave in a specific direction. In addition, the polarization control element can change the phase of light and can be operated as a variable phase element.
[0058]
The gap 1-8A between the optical fibers 1-2 was several μm to several tens μm, and the loss was almost 0 dB due to the high transmittance of ITO. In the present invention, an example of four cores is shown in the figure, but a polarization control element of one, four, eight, and twelve cores can be realized by using a commercially available splice.
[0059]
Furthermore, although not shown in the drawing of the second embodiment, when a dielectric mirror is further formed on the ITO on the end face of the optical fiber 1-2, a Fabry-Perot etalon is formed, and a voltage is applied to the liquid crystal. By doing so, it is possible to realize a variable wavelength filter.
[0060]
As described above, the case where the liquid crystal is filled has been described. However, even when an optical crystal plate having an electro-optic effect is inserted and sandwiched between the optical fibers 1-2 with a transparent electrode, the polarization can be controlled.
[0061]
In the second embodiment, the case of nematic liquid crystal has been described. However, the same effect can be obtained by using other liquid crystal, for example, ferroelectric liquid crystal.
[0062]
(Example 3)
In the third embodiment according to the present invention, while the first and second embodiments face a pair of optical fibers, a groove is dug perpendicular to one optical fiber, and then ITO is formed on the end face and side face of the optical fiber. An example is shown.
[0063]
FIG. 8 and FIG. 9 are diagrams showing a production process of the fiber optic element of Example 3, 5-1 is a protective film (coating layer) coated with polyimide or metal, 5-2 is an optical fiber core wire, 5-3 is an insulating substrate on which a V-groove 5-3A is formed, 5-4 is a polyimide for fixing an optical fiber, 5-5 is a groove formed by dicing, 5-6 is a blade of a dicing saw, 5-7 is an ITO transparent electrode formed on the wall and side surfaces, 5-8 is a liquid crystal filled in the groove, and 5-9 is an extraction electrode.
[0064]
As shown in FIG. 8 (a), a fiber optic device of Example 3 is prepared by first preparing an optical fiber in which a protective film (coating layer) 5-1 is coated with an optical fiber core 5-2. Then, a part of the protective film (coating layer) 5-1 is peeled off. The method of peeling was described in Example 1 above. Next, as shown in FIG. 8B, an insulating substrate 5-3 having a V groove 5-3A for fixing an optical fiber is prepared. Next, as shown in FIG. 8 (c), the optical fiber core wire 5-2 from which the protective film (coating layer) 5-1 has been peeled is placed in the V groove 5-3A, and polyimide 5-4 is used at 100 ° C. Warm and melt to about 300 ° C. and heat cure at about 300 ° C. The melting of the polyimide is from 50 ° C to 100 ° C, and the curing is from 200 ° C to 400 ° C. Next, as shown in FIG. 8D, a groove 5-5 having a width of about 50 μm to 100 μm is formed by a dicing saw.
[0065]
Next, as shown in FIG. 9A, ITO transparent electrodes 5-7 are formed on the wall surface and side surfaces by sputtering. In normal sputtering, the ITO transparent electrode 5-7 is formed on the wall surface to the same depth as the groove width. Accordingly, if the aspect ratio of the groove width and depth is 5 or more, the ITO transparent electrode 5-7 will not be short-circuited at the bottom of the groove 5-5. Further, since the core portion through which light passes is about 60 μm from the side surface of the optical fiber, the ITO transparent electrode 5-7 can be formed in the core portion. Since the protective film (coating layer) 5-1 and the fixing agent of the optical fiber are metal or polyimide, the substrate temperature and the heat treatment temperature of sputtering can be 100 ° C. or more and 400 ° C. Here, an ITO transparent electrode 5-7 having a substrate temperature of 100 ° C. and a thickness of about 20 nm was formed, followed by heat treatment at 350 ° C. The ITO film formed on the end face of the optical fiber had a transmittance of 98% or more in the communication wavelength band of 1.55 μm.
[0066]
Next, as shown in FIG. 9B, liquid crystal is filled. Here, the polymer network liquid crystal was filled. Next, as shown in FIG. 9C, the polymer network liquid crystal was cured by irradiating ultraviolet rays UV. As shown in the first and second embodiments, the liquid crystal may be a cholesteric-nematic phase transition liquid crystal, a polymer dispersed liquid crystal, or a dynamic scattering liquid crystal.
[0067]
The optical variable attenuator manufactured by the above process also showed the same characteristics as FIG. Compared with the first embodiment, the third embodiment does not require optical fiber insertion, fixation, and alignment, so a variable optical attenuator can be realized more easily.
[0068]
Example 4
In the first and second embodiments, the optical element in which the liquid crystal is filled between the opposing optical fibers is shown. In the fourth embodiment according to the present invention, the formation of the light emitting element on the end face of one optical fiber will be described. . That is, a semiconductor laser or a light emitting diode is usually used as a light source for an optical fiber, but a method of forming an electroluminescence (EL) element at the tip of an optical fiber as a low-speed light source will be described.
[0069]
First, in the same manner as in the above embodiment, ITO serving as a lower electrode of EL is formed on the end face and side face of a fiber having a polyimide coating and a metal coating. The conditions for forming ITO are the same as in Examples 1 and 2. The transparent electrode is not limited to ITO, and the conventionally known In₂0_Three, SnO₂Even for transparent electrodes such as ZnO, the substrate temperature and the heat treatment temperature were optimally 100 to 400 ° C.
[0070]
There are various types of EL. In the old days, ZnS was used as a base material, and a light emitting center such as Mn, Tb, Sm, etc. was added to SiO.₂And Ta₂0_FiveAC-driven inorganic thin film EL with a double insulation structure sandwiched between insulating layers such as, a DC-driven inorganic thin film EL in which ZnS: Cu, Mn is directly deposited on a transparent electrode, or a phosphor such as ZnS: Cu, Cl There is an AC-driven organic dispersion type EL in which is dispersed in an organic binder.
[0071]
Further, there is electroluminescence using a Si fine particle thin film as a light emitting layer. The Si light emitting element has been conventionally produced by making single crystal Si porous, but recently, a light emitting layer can be produced on a glass substrate by CVD or vapor deposition.
[0072]
Newly, A1q_ThreeThere is an organic thin film EL composed of an organic light emitting layer represented by the above. The modulation rate of the organic thin film EL is several MHz, and is used for FTTH as a very inexpensive light source. Recently, the organic thin film EL is sometimes referred to as an organic light emitting diode, which falls within the scope of the present invention.
[0073]
The formation temperature of these ELs is from room temperature to about 400 ° C., and it is necessary to use the heat-resistant coated optical fiber of the present invention and the technology for forming ITO thereon.
[0074]
In addition, although there exist vapor deposition, a sputtering method, etc. about the formation method of the said electrode layer, a light emitting layer, etc., there is also a method using a solution-type material, and it is simple. That is, for example, a first layer such as an electrode is formed relatively deeply in a solution (dip) to form a fiber first, and then formed as a second layer. By soaking it shallowly, it is possible to provide a region where the first layer is exposed far from the fiber tip and the electrode can be taken out, and a region where the two layers overlap. Furthermore, for example, the electrode material for the third layer can be provided with an electrode layer that is not directly connected to the first electrode but sandwiches the light-emitting layer therebetween by soaking it shallower than in the case of the two layers. In this manner, a light emitting element having an EL layer on a fiber can be easily formed by gradually decreasing the depth of immersion in a solution material. This forming method can be applied not only to the case of three layers as described above, but also to the case of providing a hole / electron transport layer, a hole / electron injection layer, a buffer layer, etc. on both sides or one side of the light emitting layer. It is clear.
[0075]
  Fiber of Example 4formA typical structure of the main part of the optical element is shown in FIGS. Here, as a typical EL, Alq_ThreeThe structure of organic thin film EL which uses as a light emitting layer is shown. 10A is an external view, FIG. 10B is a cross-sectional view taken along line AA ′ shown in FIG. 10A, and FIG. 10C is a view showing a light emission state. Is a glass fiber (optical fiber), 6-2 is a protective film (coating layer) made of polyimide or metal, 6-3 is an ITO transparent electrode, and 6-4 is Alq._Three6-5 is a back electrode, 6-6 is a back extraction electrode, 6-7 is a light emitting state, and 6-8 is an optical fiber core. The upper electrode is taken out by bonding or a prober. Here, the organic light emitting layer is shown as a single organic thin film, but may be a multilayer organic thin film. In addition to Al, Mg, In, or the like is used for the back electrode.
[0076]
When a voltage is applied between the side ITO electrode of the optical fiber and the back electrode, the light emitting layer formed at the tip of the optical fiber emits light, and the light enters the core of the optical fiber and is transmitted. The response speed of the EL is several MHz, and high-speed transmission like a semiconductor laser is impossible, but it is effective as a low-cost and small-sized light source for a low-speed optical fiber network of an access system.
[0077]
(Example 5)
In the fourth embodiment, the light emitting device in which the EL layer is formed on the transparent electrode on the end face of the optical fiber has been described. Here, the structure and manufacturing method of the device in which the surface emitting laser or the surface detector is attached are shown in FIG. Description will be made with reference to a), (b) and (c). Here, as a typical EL, Alq_ThreeThe structure of organic thin film EL which uses as a light emitting layer is shown.
[0078]
FIG. 11 is a view showing the structure of an element in which a surface emitting laser and a surface PD are attached to the tip of an optical fiber according to a fifth embodiment of the present invention, FIG. 11 (a) is an external view, and FIG. 11 (b) is (a). FIG. 11C is a cross-sectional view taken along line AA ′ shown in FIG. 11, and FIG. In FIG. 11, 7-1 is an optical fiber (glass fiber), 7-2 is an ITO transparent electrode, 7-3 is a core of the optical fiber 7-1, 7-4 is a protective film (coating layer) made of polyimide or metal. 7-5 is an extraction electrode from the side surface of the optical fiber, 7-6 is a light emitting region of the surface emitting laser, 7-7 is an extraction electrode on the back surface of the surface emitting laser, 7-8 is a substrate of the surface emitting laser, 7-9 Is a solder bump or conductive adhesive connected to the electrode on the surface of the surface emitting laser.
[0079]
Conventionally, in order to couple a semiconductor laser, a detector, and an optical fiber, the semiconductor laser is mounted on a dedicated mount, an electrode is taken out by bonding, and is aligned with the optical fiber to couple light. For this reason, it is difficult to reduce the size of the module, and further labor is required for alignment.
[0080]
In the present invention, transparent electrodes are formed on the end face and side face of an optical fiber, and the end face of the optical fiber is used as a surface emitting laser or detector mount. Since the transparent electrode is formed on the end surface and the side surface of the optical fiber, the surface element can be attached to the end surface and the electrode can be taken out from the side surface of the optical fiber.
[0081]
As shown in FIGS. 11 (a) and 11 (b), solder bumps or conductive paste (conductive adhesive 7-9) is attached to the electrodes on the surface of the surface emitting laser chip (substrate), and the ITO transparent electrode 7-2. Is attached to the tip of the optical fiber 7-1 formed on the end face and side face. In the case of solder, it is bonded by heating from 100 ° C. to 200 ° C., and in the case of a conductive paste, it is bonded at a temperature of several tens of degrees C. to 200 ° C. Alternatively, an electrode is formed so that the light emitting side (surface side) electrode of the surface emitting laser is higher than the light emitting layer, and pressed so as to contact the end face of the optical fiber 7-1. Filled between surface emitting lasers or surface detectors and heat bonded.
[0082]
As another pasting method, there is a method using a transparent conductive coating material. That is, the transparent electrode material is formed between the fiber 7-2 coated with a transparent electrode such as ITO and the surface emitting laser substrate 7-8, including the surface emitting laser light emitting region 7-6. Applying and filling, baking only with heat treatment at 200 to 400 ° C. or using vacuuming together, and bonding. According to this method, it is not necessary to mount and fill the solder bumps and the transparent adhesive with high accuracy, and the bonding process becomes easier.
[0083]
At that time, alignment is performed so that the light emitting region 7-6 of the surface emitting laser and the core 7-3 of the optical fiber 7-1 coincide. The size of the surface emitting laser is about 250 μm square, the light emitting region 7-6 is 10 μm to 50 μm, the extraction electrode can be arranged within 100 μm square, and the end face of the optical fiber 7-1 is usually 125 μmφ, It can be attached to the end face region of the optical fiber 7-1.
[0084]
Further, when a multimode fiber having a large core of 50 to 1200 μm is used as an optical fiber, it becomes easier to mount a surface emitting laser or the like. That is, if the core of the optical fiber is 50 to 1200 μm, a surface emitting laser or the like can be easily mounted. Also, the end face of the fiber coated with a transparent electrode such as ITO is processed in advance so that the structure is not flat, for example, the core region is recessed, thereby facilitating mounting and bonding of the surface emitting laser, and It can be easily mounted by a proper position.
[0085]
The surface emitting laser is caused to emit light by passing a current between the electrode 7-5 attached to the side surface of the optical fiber 7-1 and the electrode 7-7 attached to the back surface of the surface emitting laser, and the core of the optical fiber 7-1. 7-3 can output light. In this manner, a small module can be easily manufactured by simply attaching a surface emitting laser chip (substrate) to the tip of the optical fiber 7-1.
[0086]
Furthermore, arraying is possible by using a surface emitting laser array or an optical fiber array. Although only the surface emitting laser has been described here, there is a merit of miniaturization and arraying even if a surface type PD is attached to the tip of the optical fiber 7-1.
[0087]
Although the invention made by the present inventor has been specifically described based on the embodiment (example), the invention is not limited to the embodiment (example), and departs from the gist thereof. Of course, various changes can be made without departing from the scope.
[0088]
【The invention's effect】
The effects obtained by the invention disclosed in the present application will be briefly described as follows.
[0089]
According to the present invention, when optical fibers are opposed to each other and a material having optical modulation and electro-optic effect is inserted between the optical fibers, the optical axes of the optical fibers are easily matched, so that downsizing and arraying are easy it can.
[0090]
Further, a light source / detector can be easily produced on the end face of the optical fiber. In addition, an optical device in which transparent electrodes with high transmittance are formed on the end face and side face of the optical fiber can be realized.
[Brief description of the drawings]
FIG. 1 shows a fiber according to Example 1 of the present invention.formIt is a perspective view which shows schematic structure of an optical element.
FIG. 2 shows the fiber shown in FIG.formIt is a figure for demonstrating the preparation methods of an optical element.
FIG. 3 shows the fiber shown in FIG.formIt is a figure for demonstrating the preparation methods of an optical element.
Fig. 4 Transmittance of transparent electrode in communication wavelength bandTheShowing transmission spectrumLe(A) is the transmission spectrum before annealing, (b) is the transmission spectrum of 40 nm ITO annealed at 350 ° C. for 150 minutes.
FIG. 5 shows a fiber according to the first embodiment.formIt is a figure which shows the characteristic of the optical attenuator which is an optical element.
6 is a diagram showing a manufacturing process of an optical polarization control element of Example 2 according to the present invention. FIG.
7 is a diagram showing a manufacturing process of the optical polarization control element of Example 2. FIG.
FIG. 8 is a diagram showing a manufacturing process of the fiber optic device of example 3 according to the present invention.
FIG. 9 is a diagram showing manufacturing steps of the fiber optic device according to the third embodiment of the present invention.
FIG. 10 shows a fiber according to Example 4 of the present invention.formIt is a figure which shows the typical structure of the principal part of an optical element.
FIG. 11 is a diagram showing the structure of an element in which a surface emitting laser and a surface PD are attached to the tip of an optical fiber according to a fifth embodiment of the present invention.

Claims (9)

In the fiber type optical element, the fiber coating has a heat resistance of 100 ° C. or more, and is composed of an optical fiber provided with transparent electrodes on the end face and side face,
The fiber coating is made of metal or polyimide, and the transparent electrode is made of any one of indium tin oxide (ITO), In ₂ O ₃ , SnO ₂ , and ZnO, and is 100 ° C. or more and 400 ° C. A fiber-type optical element formed as described below .   A pair of optical fibers provided with the transparent electrode on the end surface and side surfaces are opposed to each other with a gap between the end surfaces, and the optical axes of both are aligned, and in the gap between the end surfaces of the optical fiber, 2. A fiber-type optical element according to claim 1, wherein a material / element having an electro-optic effect and a light modulation effect is filled or inserted, and the intensity and polarization of the light are controlled and the wavelength is selected. .   The one optical fiber is fixed to the substrate, a groove perpendicular to the optical fiber is provided, a transparent electrode is provided on the wall surface of the groove, and the groove is filled with a material / element having an electro-optic effect / light modulation effect 2. The fiber-type optical element according to claim 1, wherein the fiber-type optical element is inserted to control the intensity and polarization of the light or to select a wavelength.   The material having the electro-optic effect and the light modulation effect is any one of nematic liquid crystal, polymer dispersed liquid crystal, polymer network liquid crystal, ferroelectric liquid crystal, cholesteric-nematic phase transition liquid crystal, dynamic scattering liquid crystal, or electro 4. The device according to claim 2, wherein the element that is a chromic material and has the electro-optic effect and the light modulation effect is a semiconductor surface light modulator or an electro-optic crystal surface light modulator. 5. Fiber type optical element.   2. The fiber-type optical element according to claim 1, wherein one of an electroluminescence element, a surface emitting laser, and a surface detector is provided on a transparent electrode on an end face of the optical fiber. The electroluminescence element is one of organic thin film electroluminescence, inorganic thin film electroluminescence in which ZnS or ZnSe is doped with a light emitting element, organic dispersion type electroluminescence in which a ZnS phosphor is mixed in a binder, or ultrafine Si film The fiber-type optical element according to claim 5 , wherein the fiber-type optical element is mainly composed of one electroluminescence. The fiber coating has a heat resistance of 100 ° C. or more, and is composed of an optical fiber provided with transparent electrodes on the end surface and side surfaces, and the coating of the fiber is a method for producing a fiber-type optical element made of metal or polyimide,
A transparent electrode is formed on the end face and side face of the optical fiber by sputtering or vapor-depositing any one of indium tin oxide (ITO), In ₂ O ₃ , SnO ₂ , and ZnO, and the transparent electrode Is formed at 100 ° C. or higher and 400 ° C. or lower . A pair of optical fibers in which the transparent electrode is formed on the end surface and side surfaces are opposed to each other with a gap between the end surfaces, and the optical axes of both are aligned, and in the gap between the end surfaces of the optical fiber, The method for producing a fiber-type optical element according to claim 7 , wherein a material / element having an electro-optic effect and a light modulation effect is filled or inserted. The jig for arranging the optical fibers to face each other with their optical axes aligned is composed of any one of a V-groove, an optical fiber splice, a ferrule and an optical connector comprising a sleeve, and a microcavity. The method for producing a fiber-type optical element according to claim 8 , characterized in that:

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