JP2002228948A - Optical waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide which can directly control the light quantity of each optical fiber of an optical system using propagation of light based on an optical fiber. SOLUTION: The optical waveguide has the optical fiber which propagates light emitted from a light source, a light transmissive member, and a driving means which brings/separates the light transmissive member into contact with/ from the side face of the optical fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of light propagation through an optical fiber, and more particularly, to an optical waveguide capable of adjusting the amount of propagating light in the propagation of light using an optical fiber.

[0002]

2. Description of the Related Art Optical fibers are used for image reading devices, image recording devices, transmission of various information, and the like. In an optical system utilizing the propagation of light by such an optical fiber, the control of the light amount is usually performed by a method of arranging an ND filter or a stop in an optical path, a method of adjusting the light amount of light emitted from a light source, or the like. .

However, in such an optical system, when the number of optical fibers is large, it is difficult to control the amount of light independently for each optical fiber. For example,
When the number of optical fibers is large, it is disadvantageous in terms of cost and space to provide individual light sources, so that light emitted from one light source is often incident on a plurality of optical fibers. In this case, if the amount of light emitted from the light source is adjusted, the same amount of light changes in a plurality of optical fibers, and independent light amount control cannot be performed. On the other hand, N
By arranging a D filter or the like, it is possible to perform independent light quantity control for each, but in this case, the number of components increases according to the number of optical fibers, and the cost and size of the optical system are increased. It is disadvantageous in such points.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. In an optical system utilizing light propagation through an optical fiber, an ND filter or the like is provided for each optical fiber. It is possible to directly and independently control the light amount without using it, and even when using a large number of optical fibers, it is possible to control the light amount for each optical fiber without increasing the number of parts. The purpose of the present invention is to provide an optical waveguide that performs the following.

[0005]

In order to achieve the above-mentioned object, the present invention provides an optical fiber for transmitting light emitted from a light source, a light-transmitting member, and a light transmitting member. And a driving means for contacting / separating the optical waveguide.

In the optical waveguide of the present invention, it is preferable that a plurality of the light transmitting members are provided, and each of the light transmitting members independently comes into contact with / separates from the side surface of the optical fiber. Further, the light-transmitting member and the driving means have an electrode, an insulating layer formed on the surface of the electrode, and a convex portion separated from the insulating portion at the center, and are held by the insulating layer at an end portion. A transparent electrode having elasticity, a power supply for applying a voltage to the electrode and the transparent electrode, and the electrode so that the convex portion of the transparent electrode contacts a side surface of the optical fiber in a state where no voltage is applied by the power supply. It is preferable that the light transmitting member has a diameter larger than the optical fiber, and is partially cut,
A transparent ring through which the optical fiber is inserted, wherein the driving means is fixed to a first electrode formed integrally with one end face of the cut portion of the ring, and to the other end face of the cut portion of the ring; A second electrode forming an electrode pair with the first electrode, a power supply for applying a voltage to the first electrode and the second electrode, and an insulation for preventing contact between the first electrode and the second electrode. It is preferable to include the conductive member.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical waveguide according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIGS. 1A and 1B are schematic views showing an example of the optical waveguide of the present invention. As shown in FIG. 1A viewed from the diameter direction of the optical fiber, this optical waveguide 10
Basically, it is configured to include an optical fiber 12, a light amount adjusting element 14 in which a plurality is arranged on a side surface of the optical fiber, and a tubular holding member 16 through which the optical fiber 12 is inserted. Such an optical waveguide 10 is provided with each light amount adjusting element 14.
Are independently driven to adjust the amount of light propagated by the optical fiber 12 and to control the amount of light emitted from the emission-side end face of the optical fiber 12 (hereinafter simply referred to as emission).

In the optical waveguide 10 of the present invention, as the optical fiber 12, various types of optical fibers 12 can be used as long as at least a region corresponding to the holding member 16 does not have a clad. In addition, a single mode or a multi-mode (multi-mode) may be used.

As shown in a partial schematic cross-sectional view (diameter cross section of the optical fiber 12) of FIG. 1B, each light amount adjusting element 14 is fixed to an inner surface of a holding member 16. The holding member 16 is inserted through the optical fiber 12 such that the inner surface of the holding member 16 has a predetermined gap with the side surface of the optical fiber 12. In the illustrated example, as a preferred embodiment, a spacer 18 (preferably a refractive index) is used. Is optical fiber 12 or less)
Is used to maintain the gap between the two.

As long as the holding member 16 can be insulated from the light amount adjusting element 14, a diameter corresponding to the diameter of the optical fiber 12, the size of the light amount adjusting element 14 (particularly the size in the diameter direction of the optical fiber 12), and the like, Various tubular members having a length corresponding to the position of the light amount adjusting element 14 in the longitudinal direction of the optical fiber can be used, and may be light-transmissive or light-shielding. However, it is preferable that the holding member 16 has such a rigidity that the transparent electrode 24 described later does not needlessly contact the side surface of the optical fiber 12 when the optical waveguide 10 receives an external force or the like.

The light quantity adjusting element 14 includes a fixed electrode 20 fixed to the inner surface of the holding member 16, an insulating layer 22 laminated on the upper surface of the fixed electrode 20 (center side of the optical fiber 12), and fixed on the upper surface of the insulating layer 22. Transparent electrode 24 and power supply 26 for applying a voltage to fixed electrode 20 and transparent electrode 24
Is configured.

The material for forming the fixed electrode 20 and the insulating layer 22 is not particularly limited, and various materials can be used.
For example, silicon (Si) is used for the fixed electrode 20, and silicon oxide (SiO ₂ ) is used for the insulating layer 22, respectively. The transparent electrode 24 forming an electrode pair with the fixed electrode 20 is an elastic plate spring-like electrode formed of a transparent conductive material having a refractive index equal to or higher than that of the optical fiber 12, and is, for example, ITO (Indium Tin Oxide). ). In the illustrated example, the transparent electrode 24 has a convex portion 24a formed by bending a leaf spring at the center, and is fixed to the insulating layer 22 at the end in the direction of forming the irregularities. It is separated from the insulating layer 22.

The light amount adjusting means 14 includes a power source 26
1B is not driven, and as shown by the solid line in FIG. 1B, the projection 24 a of the transparent electrode 24 is held on the inner surface of the holding member 16 so as to contact the side surface of the optical fiber 12. .

In the optical waveguide 10 of the illustrated example, such a member and the light amount adjusting element 14 formed by the power source 26 are used.
Is a MEMS (Micro Electro Mechani
calSystem). Further, such a light amount adjusting element 14 may be manufactured by a known method using a manufacturing technique of a micromachine or a semiconductor device.

In the optical waveguide 10 of the illustrated example, when the power supply 26 is not driven (off), each light amount adjusting element 14 has a convex portion of the transparent electrode 24 as shown by a solid line in FIG. 24a is in contact with the side surface (boundary surface) of the optical fiber 12. Therefore, in this state, the refractive index of the boundary surface of the optical fiber 12 has changed, and the component of the light transmitted through the optical fiber 12 that has entered the contact position of the transparent electrode 24 is the boundary surface of the optical fiber 12. And is released to the outside. That is, the amount of light propagated and emitted by the optical fiber 12 is reduced by this amount.

On the other hand, when the power supply 26 is driven (on) and a voltage is applied between the fixed electrode 20 and the transparent electrode 24,
Static electricity is generated between the two portions, which are insulated by the insulating layer 22 and have both ends fixed and having a gap formed by the convex portions 24a. This static electricity causes the fixed electrode 20 and the transparent electrode 2
4, an attractive force is generated between the transparent electrodes 24 and
Is pulled by the fixed electrode 20, and as a result,
As shown by the dotted line in FIG. 1B, the convex portion 24a moves away from the boundary surface of the optical fiber 12. Therefore, the power supply 26
The light component emitted from the contact portion of the transparent electrode 24 at the time of turning off the optical fiber 12
And is emitted by
The amount of light that is propagated to the optical fiber 12 and emitted therefrom is larger than that in the off state.

Further, the power supply 26 is turned off from the on state.
Then, the attractive force due to the static electricity disappears, and the transparent electrode 2
4 returns to its original state due to its own elasticity, and is in the state shown by the solid line in FIG.

That is, according to the optical waveguide 10 shown in FIG. 1, the light amount of the light propagated by the optical fiber 12 can be adjusted by turning on / off the drive power supply. If 26 is turned on, all light incident on the optical fiber 12 is propagated and emitted from the emission end face, and the amount of emitted light can be reduced according to the number of light amount adjustment elements 14 with the power supply 26 turned off. . For example, 32 independently drivable light amount adjusting elements 14
, The power supply 2 of all the light amount adjusting elements 14
The light amount of the light emitted from the optical fiber 12 can be adjusted in 33 steps, including the state where 6 is off.

As is apparent from the above description, according to the optical waveguide of the present invention, in the optical system utilizing the light propagation by the optical fiber 12, the ND filter is not used for each optical fiber 12 and the light source The amount of light emitted from each optical fiber 12 can be independently controlled for each optical fiber 12 without adjusting the amount of light.

The optical waveguide 10 of the present invention is not limited to having a plurality of light quantity adjusting elements 14 (light transmitting members) as described above, but may have one light quantity adjusting element 14. However, as described above, by having a plurality of light amount adjusting elements 14 and driving each independently,
It is more preferable that the amount of light emitted from the optical fiber 12 can be adjusted stepwise according to the number of the light amount adjusting elements 14 that can be independently controlled. Further, in the illustrated example, a power supply is provided for each of the light amount adjusting elements 14, but the present invention is not limited to this, and a single power supply may be shared by a plurality of light amount adjusting elements 14. Good.

In the illustrated example, the light amount adjusting elements 14 are arranged corresponding to the circumferential and longitudinal side surfaces of the optical fiber 12, but the present invention is not limited to this. , May be arranged only in the circumferential direction or only in the longitudinal direction. Further, instead of the tubular holding means 16, a flexible band-shaped supporting means is used,
Similar light amount adjusting element 14 or further spacer 18
May be formed, and this band may be wound around the optical fiber 12 (either circumferentially or spirally) to form the optical waveguide of the present invention.

FIG. 2 is a schematic view showing another example of the optical waveguide of the present invention. In FIG. 2, the same members as those of the optical waveguide 10 shown in FIG.
Mainly in different parts.

FIG. 2 shows a cross section of the optical fiber 12 in the diameter direction. This optical waveguide 30 basically has the same optical fiber 12 and the light amount adjusting means 32 as in the above-described example. It is composed. In this example, at least a portion of the optical fiber 12 corresponding to the optical path adjusting means does not have a clad.

The light amount adjusting means 32 basically includes a transparent ring 34, a first electrode 36 and a second electrode 38, an insulating material 40, and the same power supply 26 as described above. The transparent ring 34 is a ring-shaped member formed of a light-transmitting material having a refractive index equal to or higher than that of the optical fiber 12, having a diameter larger than that of the optical fiber 12, and partially cut / removed. Has the same elasticity as a so-called ring spring. A first electrode 36 is provided at one end of the cut portion of the transparent ring 34.
However, a second electrode 38 is fixed to the other end, and forms an electrode pair separated by a predetermined distance. In addition, an insulating material 40 for preventing contact between the two electrodes is disposed in a portion of the second electrode pair 38 facing the first electrode 36. Further, the power supply 26 for applying a voltage to both the first electrode 36 and the second electrode 38 is connected.

The light amount adjusting means 32 includes a power source 26
2A, the transparent ring 34 is inserted through the optical fiber 12 without contact between the inner surface of the transparent ring 34 and the side surface of the optical fiber 12 as shown in FIG. , Held by known means.

Also in this optical waveguide 30, the light quantity adjusting element 32 is a MEMS driven by static electricity, and, similarly to the previous example, using a known material and a micromachine or a semiconductor device manufacturing technique. What is necessary is just to manufacture by a well-known method.

In the optical waveguide 30, the light amount adjusting element 32
When the power supply 32 is off, the transparent ring 34 is not in contact with the side surface (boundary surface) of the optical fiber 12 as shown in FIG.
All the components of the light incident on 2 are propagated and emitted.

When the power supply 32 is turned on and a voltage is applied between the first electrode 36 and the second electrode 38, static electricity is generated between the two electrodes separated by a predetermined distance, thereby generating an attractive force. As shown in FIG.
And the second electrode 38 attract each other and approach each other. In the illustrated example, since the insulating material 40 is disposed on the second electrode 38, they do not come into contact with each other, and no short circuit occurs. As shown in FIG. 2B, when the diameter of the transparent ring 34 is reduced due to the proximity of the two electrodes, the transparent ring 34 comes into contact with the side surface, that is, the boundary surface of the optical fiber 12. Thereby, the refractive index of the boundary surface of the optical fiber 12 changes,
Of the propagated light, the component incident on this contact position is
The light is refracted, passes through the boundary surface of the optical fiber 12, and is emitted to the outside of the optical fiber 12. In other words,
The amount of light emitted from the optical fiber 12 is reduced.

Further, the power supply 26 is turned off from the on state.
Then, the attractive force due to the static electricity disappears, the transparent ring 34 returns to its original state by its own elasticity, and the state shown in FIG.

That is, also in the optical waveguide 30 shown in FIG. 2, the amount of light propagated and emitted by the optical fiber 12 can be adjusted by turning on / off the driving power supply. Also, as described above, FIG. 2 shows a cross-sectional view of the optical fiber 12 in the diameter direction, and therefore, only one light amount adjusting means 32 is shown. A plurality of light amount adjusting means 3 in the direction
2 may be provided, so that the amount of light emitted from the optical fiber 12 can be adjusted stepwise. In addition, one power supply 2 is
6 may be shared.

Although the optical waveguide of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various improvements and modifications may be made without departing from the spirit of the present invention. Is, of course.

[0033]

As described in detail above, according to the optical waveguide of the present invention, even if a large number of optical fibers are used in an optical system utilizing the propagation of light by optical fibers, individual The amount of light emitted from the optical fiber can be adjusted independently.

[Brief description of the drawings]

FIG. 1 is an example of an optical waveguide of the present invention, in which (A) is a schematic diagram viewed from a diameter direction of an optical fiber, and (B) is a partial schematic cross-sectional view cut in a diameter direction of the optical fiber.

FIGS. 2A and 2B are schematic sectional views of another example of the optical waveguide of the present invention, which are cut in the diameter direction of the optical fiber.

[Explanation of symbols]

 Reference Signs List 10, 30 Optical waveguide 12 Optical fiber 14, 32 Light amount adjusting element 16 Holding member 18 Spacer 20 Fixed electrode 22 Insulating layer 24 Transparent electrode 26 Power supply 34 Transparent ring 36 First electrode 38 Second electrode 40 Insulating material

Claims (4)

[Claims] 1. An optical waveguide comprising: an optical fiber for transmitting light emitted from a light source; a light transmitting member; and driving means for contacting / separating the light transmitting member from / to a side surface of the optical fiber. Wave path. 2. The optical waveguide according to claim 1, comprising a plurality of said light transmitting members, wherein each of said light transmitting members independently comes into contact with / separates from the side surface of the optical fiber. 3. The light-transmissive member and the driving means include: an electrode; an insulating layer formed on the surface of the electrode; and a convex portion at the center and separated from the insulating portion. Retained, a transparent electrode having elasticity, a power supply for applying a voltage to the electrode and the transparent electrode, and contacting the convex portion of the transparent electrode with a side surface of the optical fiber in a state where no voltage is applied by the power supply. The optical waveguide according to claim 1, further comprising: a support member configured to support the electrode. 4. The optical transmission member is a transparent ring having a diameter larger than that of the optical fiber and partially cut through the optical fiber. A first electrode integrally formed with one end face of the cut portion, a second electrode forming an electrode pair with the first electrode, formed constantly on the other end face of the cut portion of the ring, The optical waveguide according to claim 1, further comprising: a power supply that applies a voltage to the first electrode and the second electrode; and an insulating member that prevents contact between the first electrode and the second electrode. .