JPH05173088A - Optical waveguide driving device - Google Patents

Abstract

PURPOSE:To obtain a compact and light optical waveguide driving device capable of executing optical scanning by providing the device with an optical waveguide means such as an optical waveguide or an optical fiber supported by a cantilever and at least one electrode or magnetic circuit for deflecting the free end side of the optical waveguide means. CONSTITUTION:This driving device is provided with the optical fiber 1 supported by the cantilever and an electrode group arranged around a deflection area 5 of the fiber 1 and consisting of horizontal deflection electrodes 8a, 8b which are mutually parallel and vertical deflection electrodes 9a, 9b which are mutually parallel. When positive voltage is impressed to any one of the deflecting electrodes and the residual electrodes are grounded, the deflection area 5 of the fiber 1 is attracted by electrostatic attractive force and positioned on a position balanced with restoring force determined by the spring constant of the fiber 1. In this state, light 12 projected from light projection end 2 is deflected. Thus the two-dimensional deflection of light can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of an optical waveguide driving device.

[0002]

2. Description of the Related Art In recent years, computers have been remarkably spread, and have become indispensable for promoting labor saving and high efficiency such as OA, FA and LA. Compu
With the spread of data, there is a strong demand for downsizing, price reduction, and high performance of printers for data output. Especially, optical printers have advantages such as clear printing and low noise. It is definitely increasing.

An important functional element of an optical printer is the convergence and polarization of laser light, and in particular, research and development of an optical deflector that is small in size and capable of performing high precision is required. Optical deflectors that have been put to practical use or have been researched and developed include polygon mirror type using a reflecting mirror, galvanometer mirror type, and cantilever type, and waveguide type using acousto-optical effect. and so on. The polygon mirror type is the most popular optical deflector that uses the side surface of a rotating polyhedron as a reflecting mirror, but it is required to be lightweight and compact in terms of weight and volume. Galvano mirror type and cantilever type have electromagnetic force,
This is a reflecting mirror that uses electrostatic force, and is an advantageous method for reducing size and weight, but there is room for improvement in terms of deflection accuracy.
A diffractive optical deflector that uses the acousto-optic effect of a ferroelectric substance can change the deflection angle with high accuracy by changing the frequency of the high-frequency voltage applied to the comb-shaped electrodes, but the deflection angle is as small as a few degrees and is still in practical use. Has not reached the level of.

Further, all of the light deflection methods only perform one-dimensional scanning of light, and two deflection means must be combined to perform two-dimensional scanning, which complicates the apparatus configuration.

[0005]

However, the polygon mirror used in the conventional optical printer has a problem of downsizing and weight saving. Further, the galvanometer mirror and the cantilever mirror are required to improve the deflection accuracy, and the diffraction type deflector using the acousto-optic effect is required to enlarge the deflection angle. Further, the conventional deflection methods that have been put to practical use have a limitation that it is difficult to two-dimensionally deflect light. The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical waveguide driving device having a small size, a light weight, and a simple structure.

[0006]

According to the present invention, there is provided an optical waveguide driving device comprising a cantilevered optical waveguide means and a driving means for deflecting the free end side of the optical waveguide means. is there. In the present invention, the optical waveguide means may be an optical fiber or cantilever type optical waveguide coated with a conductive thin film.

In the present invention, as the driving means,
One or more electrodes electrically insulated from the optical waveguide means and capable of independently applying a voltage, one or more magnetic circuits for generating a magnetic field, or a piezoelectric element, for example A mechanical drive source is mentioned.

[0008]

In the present invention, when an optical fiber coated with a thin film having conductivity, for example, is used as the optical waveguide means, it is electrically insulated around the emitting end of the optical fiber and independently applied with a voltage. Electrodes (driving means) that can be applied are arranged. Then, the conductive thin film is grounded, and by applying a positive or negative voltage to the driving means fixedly arranged,
Electrostatic force is generated between the optical fiber and the drive electrode, and by selecting the drive electrode and appropriately selecting the applied voltage, the light emission end from the optical fiber can be moved and light scanning is possible. become.

An optical fiber coated with a magnetic thin film
By arranging a magnetic circuit for generating a magnetic field near the light input / output end of this optical fiber, and driving the magnetic circuit here, the optical fiber-by controlling the magnetic field distribution near the output end, Two-dimensional scanning of light entering and exiting the optical fiber is possible.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 Reference is made to FIG. The first embodiment is an apparatus for two-dimensionally deflecting light by two-dimensionally displacing an optical fiber by using electrostatic force.

Reference numeral 1 in the figure denotes an optical fiber for propagating light. This optical fiber-1 has a fixing region 3 for fixing the position of the optical fiber-1 to the light emitting end 2.
It is divided into a taper region 4 and a deflection region 5 having a uniform thickness. A jig 6 for fixing the position of the optical fiber-1 is arranged in the fixing region 3. The deflecting region 5 of the optical fiber-1 is covered with a metal thin film (hatched portion in FIG. 1) 7 on its surface, and its diameter is reduced to several mmφ so as to facilitate electrostatic deflection. The metal thin film 7 is grounded.

Around the deflection region 5, two horizontal deflection electrodes 8a and 8b and two vertical deflection electrodes 9a and 9b are fixedly arranged. Here, the horizontal deflection electrodes 8a, 8
b are arranged parallel to each other to form a pair, and the vertical deflection electrodes 9
a and 9b are also arranged in parallel with each other to form a pair. The surface of each deflection electrode is insulated. A bias circuit 10 capable of independently applying a voltage is connected to each of the deflection electrodes. Each of the bias circuits 10 is controlled by a bias control circuit 11 for electrostatically deflecting the deflection area 5 of the optical fiber-1.

In the apparatus having such a structure, for example, when a positive voltage is applied to the vertical deflection electrode 9a and the other vertical deflection electrodes 9b and the horizontal deflection electrodes 8a and 8b are grounded, the deflection area 5 of the optical fiber-1. Is pulled upward by electrostatic attraction and is positioned at a position that balances with the restoring force determined by the spring constant of the optical fiber-1. At this time, the light 12 emitted from the light emitting end 2 is deflected upward. The other deflection electrodes 9b, 8a, 8b are also vertical deflection electrodes 9a.
By applying a voltage in the same manner as above, the deflection region 5 of the optical fiber-1 can be two-dimensionally deflected, and the light can be two-dimensionally deflected.

The optical waveguide driving device according to the first embodiment is arranged such that the cantilevered optical fiber -1 and the horizontal deflection electrodes which are arranged around the deflection area 5 of the optical fiber -1 and are parallel to each other. 8a, 8b and an electrode group including vertical deflection electrodes 9a, 9b parallel to each other. Therefore, by applying a positive voltage to any one of the deflection electrodes and grounding the other remaining deflection electrodes, the deflection region 5 of the optical fiber-1 is attracted by the electrostatic attraction, and the spring of the optical fiber-1 is attracted. It is positioned at a position that balances the restoring force determined by a constant. Further, at this time, the light 12 emitted from the light emitting end 2 is deflected, and two-dimensional deflection of light can be realized. (Embodiment 2) Referring to FIG. The second embodiment is an apparatus for two-dimensionally deflecting light by two-dimensionally displacing an optical fiber by a magnetic force.

Reference numeral 21 in the figure denotes an optical fiber for propagating light. The optical fiber 21 is divided into a fixed region 23 for fixing the optical fiber 21 toward the light emission end 22, a taper region 24, and a deflection region 25 having a uniform thickness.
A jig 26 for fixing the position of the optical fiber 21 is arranged in the fixing area 23. On the surface of the deflection area 25 of the optical fiber-21, a magnetic thin film (hatched portion in FIG. 2)
27 are worn. The light emitting end of the optical fiber-21
Magnetic circuits 28a and 28b are arranged around the vicinity of 22. One magnetic circuit 28a is located below the deflection region 25, and is composed of a core 30a made of a magnetic material having an air gap 29a and an exciting coil 31a. A bias circuit 32 is connected to the exciting coil 31a. Here, by supplying the exciting current 33 from the bias circuit 32 to the exciting coil 31a, a magnetic flux flows to the magnetic circuit 28a. The magnetic flux flows through the core 30a, which is a magnetic material having a high magnetic permeability, but the optical fiber 21
It leaches to the side and attracts the deflection region 25 with the magnetic thin film 27 adhered thereto. The deflection area 25 is positioned at a position determined by the magnetic attraction and the spring constant of the optical fiber-21. At this time, the emission end 22 of the light is deflected downward, and accordingly the emission light 34
Is also deflected downward. By arranging a similar magnetic circuit above the optical fiber 21 and with the air gap 29a facing downward, the emitted light 34 can be deflected upward (not shown in FIG. 2).

The magnetic circuit 28b is located in the lateral direction of the optical fiber 21, and is composed of a core 30b made of a magnetic material having an air gap 29b and an exciting coil 31b. A bias circuit 35 is connected to the exciting coil 31b. Here, by causing the exciting current 36 to flow from the bias circuit 35 to the exciting coil 31b, a magnetic flux flows to the magnetic circuit 28b. Here, from the bias circuit 35 to the exciting coil
The magnetic flux induced by the exciting current 36 flowing through 31b flows through the core 30b, which is a magnetic material having a high magnetic permeability,
At the portion of the air gap 29b, it seeps out to the optical fiber-21 side and pulls the optical fiber-21. Along with this, the light emitting end 22 moves in the horizontal direction toward the magnetic circuit side, and the emitted light 34 is also deflected in the horizontal direction. By arranging the magnetic circuit 28b on the side opposite to the magnetic circuit 28b, horizontal deflection is possible in the same manner.

A bias circuit for exciting the exciting coils 31a, 31b is controlled by a bias control circuit 37, and the emitted light 34 can be two-dimensionally deflected by controlling the excited states of the magnetic circuits 28a, 28b. .. Further, in FIG. 2, the magnetic circuits 28a and 28b are arranged at two positions below and on the side of the optical fiber 21 for simplification, but they may be arranged vertically and horizontally to perform two-dimensional deflection of the emitted light 34. It is possible.

The optical waveguide drive apparatus according to the second embodiment is provided with a cantilevered optical fiber 21 as described above, and magnetic circuits arranged below and laterally below the deflection region 25 of the optical fiber 21. It is configured to include 28a and 28b.
Therefore, a bias circuit is added to the exciting coil 31a (or 31b).
A magnetic circuit can be generated by passing an exciting current from 32 (or 35).
A magnetic flux flows through 28a (or 28b), and the magnetic flux permeates to the optical fiber-21 side in the air gap part of the core, and the magnetic thin film.
The deflection area 25, on which 27 has been applied, is attracted. At this time, the light emitting end 22 of the light is deflected downward (or laterally), and the emitted light 34 is also deflected downward (or laterally) accordingly. That is, by controlling the excitation states of the magnetic circuits 28a and 28b, the emitted light 34
The two-dimensional deflection of can be realized.

In the second embodiment, for the sake of simplicity, the magnetic circuits are arranged at two positions below and in the lateral direction of the deflection area of the optical fiber. However, the present invention is not limited to this. It is also possible to arrange and perform two-dimensional deflection of emitted light. (Example 3)

First, a method for manufacturing an electrostatic deflection electrode manufactured by micromachining using the LIGA process and fine electric discharge machining will be described with reference to FIGS. 3 and 4. However, this case is a case where eight deflection electrodes are concentrically provided on a silicon substrate.

(1) First, after forming the thermal oxide films 42a and 42b on the upper and lower surfaces of the silicon substrate 41, the thermal oxide film 42a on the upper surface of the substrate is formed.
A metal film 43 made of Au is formed thereon (see FIG. 3A). This metal film 43 is made of, for example, Au / Cr, Pt / Ti.
It may be a multilayer film. Subsequently, the metal film 43 is selectively etched by a photolithography technique to form a metal film pattern.
43a is formed (see FIG. 3B).

(2) Next, 3 corresponding to the height of the deflection electrode
After applying a thick resist 44 having a thickness of about 00 μm on the thermal oxide film 42a and the metal film pattern 43a, the resist 44 corresponding to the deflection electrode is removed by X-ray exposure so that its cross-sectional shape is substantially vertical. An opening 44a is formed by opening (see FIG. 3C). Next, the opening 44 of the resist 44
Ni is embedded in a by plating to form a plurality of cylindrical deflection electrodes 45 at the same time (see FIG. 3D).

(3) Next, the resist 44 is removed. Here, the plurality of deflection electrodes 45 are formed in a state of being electrically connected to each other (see FIGS. 3E and 4). In FIG. 4, 46 is a metal film pattern 43.
This is a region where a does not exist. Then, using a fine electric discharge machining method, a metal film pattern 43a, a thermal oxide film 42a, a substrate 41
Then, the thermal oxide film 42b is hollowed out to form a circular through hole 47 (see FIG. 3F). At this point, the deflection electrodes 45 are electrically separated.

(4) Next, a lead wire 48 is connected to the metal film pattern 43a by a wire bonding method to manufacture an optical fiber deflector 49 (see FIG. 3G). As a result, by pulling out the lead wire 48 from the metal film pattern 43a, a voltage can be independently applied to each deflection electrode 45.

As shown in FIG. 5, an optical fiber 50 having a diameter of several μm and a surface coated with a metal thin film is inserted into the through hole 47 of the optical fiber-deflecting device 49 obtained as described above. The base portion 51 of the optical fiber 50 is fixed by a fixing jig 52. The deflecting device 49 is also fixed after inserting the optical fiber 50.

Thus, the optical waveguide driving device according to the third embodiment has a cantilevered optical fiber 50 and a plurality of optical fibers 50 which deflect the light emitting direction toward the light emitting end side of the optical fiber 50. It is configured to include a columnar deflection electrode 45. Therefore, the two-dimensional deflection of light can be realized as in the case of the first embodiment. (Embodiment 4) First, a method of manufacturing an electrostatic deflecting device will be described with reference to FIGS.

(1) First, a plurality of first pads made of AI (aluminum) are formed on the back surface of the N-type silicon substrate 61.
62 are formed radially (see FIGS. 6A and 7). However, FIG. 7 is a rear view of FIG. Next, the first
With the surface where the pad 62 is formed facing down,
61 is held on a quartz holder (not shown) at room temperature, the upper part is heated by a halogen lamp 63, and held at about 1200 ° C. for several minutes. During the heating, a steep temperature gradient is formed in the thickness direction of the substrate 61, and AI and silicon become a eutectic alloy 64, which moves upward along this temperature gradient to move the P-type silicon layer 65 inside the substrate. Is formed so as to penetrate (FIG. 6).
(See (B)).

(2) Next, after the P type silicon layer 65 is formed up to the front surface side of the substrate 61, both surfaces of the substrate 61 are once lapped and then polished and planarized. Next, insulating film 66
After depositing a and 66b on both sides of the substrate 61, contact holes are formed on the insulating film 66a corresponding to the second pad formation planned portion.
The line 67 is formed (see FIG. 6C). Further, after depositing AI on the contact hole 67 by a sputtering method,
A second pad (deflection electrode) 68 which makes ohmic contact with the silicon layer 65 is formed by heat treatment (see FIG. 6D).

(3) Next, the insulating film 66 is formed by fine electric discharge machining.
a, the substrate 61 and the insulating film 66b are hollowed out to form a circular through hole
Forming 69. As a result, eight P-type silicon layers 65 electrically separated by PN junction are exposed on the side surface of the through hole 69. Subsequently, a lead wire 70 is connected to each of the deflection electrodes 68 by a wire bonding method to manufacture an electrostatic deflection device 71 (see FIGS. 6E and 8).

The electrostatic deflector 71 shown in FIGS. 6 (E) and 8 is shown.
As shown in FIG. 9, an optical fiber 72 having a diameter of several μm and a surface coated with a metal thin film is inserted into the through hole 69 of FIG. The root portion 73 of the optical fiber 72 is fixed by a fixing jig 74. The electrostatic deflection device 71 is also fixed after the optical fiber 72 is inserted.

Thus, the optical waveguide driving device according to the fourth embodiment has a cantilevered optical fiber 72 and a plurality of optical fibers 72 for deflecting the light emitting direction toward the light emitting end side of the optical fiber 72. It is configured to include a columnar deflection electrode 45. Therefore, the two-dimensional deflection of light can be realized as in the case of the first embodiment. (Fifth Embodiment) First, a method of manufacturing a fine optical waveguide will be described with reference to FIG.

(1) First, a concave groove 82 having a hemispherical cross section is formed on a silicon substrate 81 having a (100) crystal plane by isotropic etching using a resist or an insulating film such as a thermal oxide film as a mask (FIG. 10 (A)). Here, a substrate made of a compound semiconductor such as GaAs may be used instead of the silicon substrate because of its good cleavage property. Continuing,
After removing the mask, the low refractive index insulating (glass) film 8
3. A high-refractive-index insulating (glass) film 84 is sequentially deposited so that the lowest position 85 of the high-refractive-index insulating film 84 substantially coincides with the height of the surface of the substrate 81 (see FIG. 10 (B)). ).

(2) Next, the high-refractive-index insulating film 84 and the low-refractive-index insulating film 83 are polished to leave these insulating films only in the concave groove 82 (see FIG. 10C). Next, after depositing the low melting point low refractive index film 85 on the entire surface, the low melting point low refractive index (glass) film 85 is left only in the region where the concave groove 82 exists by photolithography (FIG. 10 (D), ( See E)). Here, FIG. 10 (E) is a perspective view of FIG. 10 (D). The low refractive index insulating film 83, the high refractive index insulating film 84, and the low melting point low refractive index film 85 form an optical waveguide. The direction of the concave groove 82 formed on the substrate 81 and the pattern forming direction of the low melting point low refraction film 85 are selected to be the <110> direction.

(3) Next, the substrate 81 is etched with an alkaline anisotropic etching solution using the low melting point and low refraction film 85 as a mask to form a waveguide type cantilever 86 (see FIG.
10 (F)). Here, as the anisotropic etching solution, for example, an ethylenediamine, NH ₄ OH / H ₂ O ₂ based etching solution is used for a silicon substrate.
Subsequently, heat treatment is performed to soften the low-melting point low-refractive index film 85, round the convex portions, and shape the cross section of the waveguide type cantilever 86 into a shape close to a circle (see FIG. 10G).

In the optical waveguide driving device according to the fifth embodiment, however, the waveguide type cantilever 86, which is one of the components, is formed of a thin film, so that the mass is small and the optical fibers of the third and fourth embodiments are the same. By replacing it, it is suitable for high-speed two-dimensional deflection. (Example 6)

FIG. 11 shows an example of a mechanical driving means which is one constitution of the optical waveguide driving device according to the present invention. This mechanical drive means is composed of a support 91, a first bimorph piezoelectric element 92 attached to the side wall of the support 91, and a second bimorph piezoelectric element 93 attached to the upper surface of the support. Has been done. The piezoelectric elements 92 and 93 are configured to cross each other, and the second member 94 of the type that expands in the opposite direction from the first member 94a of the type that contracts when a voltage is applied.
b. In addition, reference numeral 95 in the drawing denotes a light emitting end of the optical fiber. Further, the piezoelectric elements 92 and 93 move as shown by arrows.

[0037]

As described above in detail, according to the present invention, the optical waveguide means supported in a cantilever manner and the driving means for deflecting the free end side of the optical waveguide means are provided, so that the conventional optical waveguide means is provided. It is possible to provide an optical waveguide driving device which is small and lightweight, and which can scan the light entering and exiting the end of the optical waveguide.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an apparatus for two-dimensionally deflecting light by two-dimensionally displacing an optical fiber using electrostatic force according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an apparatus for two-dimensionally deflecting light by two-dimensionally displacing an optical fiber by a magnetic force according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing, in the order of steps, a method for manufacturing an electrostatic deflection electrode, which is manufactured by micromachining using a LIGA process and fine electric discharge machining, according to a third embodiment of the present invention.

FIG. 4 is a plan view of FIG.

FIG. 5 is an explanatory view of a state in which an optical fiber having a surface coated with a metal thin film is inserted into the through hole of the optical fiber deflector shown in FIG.

6A to 6C are cross-sectional views showing a method of manufacturing an electrostatic deflection device according to a fourth embodiment of the present invention in the order of steps.

FIG. 7 is a rear view of FIG.

FIG. 8 is a rear view of FIG.

FIG. 9 is an explanatory view showing a state in which an optical fiber whose surface is coated with a metal thin film is inserted into a through hole of the electrostatic deflection device of FIG. 6 (E).

FIG. 10 is an explanatory view showing the method of manufacturing the optical waveguide according to the fifth embodiment of the present invention in the order of steps.

FIG. 11 is a schematic explanatory view of a mechanical driving means which is one configuration of the optical waveguide driving device according to the sixth embodiment of the present invention.

[Explanation of symbols]

1, 21, 50, 72 ... Optical fiber, 2, 22 ... Light emitting end,
3, 23 ... Fixed area, 4, 24 ... Taper area, 5, 25 ... Deflection area, 6, 26, 52, 74 ... Fixing jig, 7, 27 ... Conductive thin film, 8a, 8b ... Horizontal deflection Electrodes, 9a, 9b ... Vertical deflection electrodes, 10 ... Bias circuit, 11, 37 ... Bias control circuit,
28a, 28b ... Porcelain circuit, 29a, 29b ... Air gap, 30
a, 30b ... core, 31a, 31b ... coil, 32, 35 ... bias circuit, 33, 36 ... exciting current, 41, 61, 81 ... silicon substrate, 45, 66 ... deflection electrode, 47 ... through hole, 48 ... Lead wire,
49 ... Optical fiber-deflecting device, 62 ... First pad, 64 ... Eutectic alloy, 65 ... P-type silicon layer, 82 ... Concave groove, 83 ... Low refractive index insulating film, 84 ... High refractive index insulating film, 85 ... Low melting point refractive index film, 86
... Waveguide type cantilever.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01S 3/107 8934-4M

Claims (3)

[Claims] 1. An optical waveguide drive device comprising: a cantilevered optical waveguide means; and a drive means for deflecting the free end side of the optical waveguide means. 2. The optical waveguide driving device according to claim 1, wherein the driving means is at least one electrode electrically insulated from the optical waveguide means and capable of independently applying a voltage. 3. The optical waveguide driving device according to claim 1, wherein the driving means is at least one magnetic circuit for generating a magnetic field.