JPS61110025A - Side leaked light collection apparatus for optical fiber - Google Patents

Abstract

PURPOSE:To achieve a higher reliability of a measuring data, by providing a light receiving section at a specified position of a cylindrical mirror body having a reflecting surface inside. CONSTITUTION:A cylindrical mirror body 1 is made up of a reflecting surface forming layer 3 in which a metal with a high reflectance of light such as Ag and Au deposited or coated on the circumferential surface of a transparent glass tube 2. An optical fiber 4 is forced into the mirror body 1 and a light receiving section 6 is provided at a specified position at one side end of the mirror body 1. Then, as the maximum quantity of light 9 leaked from the optical fiber 4 through which is passing from a light source 5 depending on the position of light at a fine angle to the axis of the optical fiber 4, very limited quantity of light is obtained only by bringing a photodiode, for instance, close to the optical fiber 4. Therefore, leaked light is reflected at the closest distance to the optical fiber 4 to collect with the mirror body 1. So to speak, the mirror body 1 prevents diffusion the leaked light to allow the collection of light. Moreover, the leaked light thus collected is fed to the light receiving section 6 to measure the quantity of the light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device that efficiently collects light leaking from the side surface of an optical fiber.

[Prior art]

Conventionally, attempts have been made to measure light leakage from the side surfaces of optical fibers through which light passes.

For example, two fibers may be aligned in parallel.

A known method is to introduce light from one end of one optical fiber by twisting the fibers together, and measure the light leaking to one end of the other fiber.

However, in the case of this method, @the light itself is faint,
There was a problem that the amount of light was insufficient. Therefore, methods such as increasing the input optical power or increasing the length of the two optical fibers are considered, but if the fibers are long, measurement cannot be easily performed.

There are limits.

Furthermore, since bending the optical fiber slightly increases the amount of light leakage, there is also a method of locally bending the optical fiber. However, if only one part is bent, the amount of light is insufficient and it is necessary to bend several parts, and the equipment becomes complicated, and the optical transmission characteristics of the optical fiber will be affected later. There is.

That is, it is important to increase the amount of light leakage collected by a simple method while keeping the optical fiber in its natural shape.

[Problem that the invention seeks to solve]

The present inventors have conducted intensive studies to provide an optical fiber side condensing device that does not have the above-mentioned drawbacks, especially a device that can condense a large amount of light from the fiber side without deforming the optical fiber.As a result, the present invention has been achieved. It has been reached.

That is, one object of the present invention is to provide an optical fiber side light leakage condensing device with significantly improved light condensing efficiency.

[Means for solving problems]

This object of the present invention is achieved by an optical fiber side light leakage and condensing device comprising a cylindrical mirror body having a reflective surface inside and a light receiving section provided at a predetermined position of the cylindrical mirror body.

The details of the present invention will be explained below with reference to FIGS. 1 and 2. FIG. 1 illustrates an example of a side light leakage condensing device for an optical fiber according to the present invention. In FIG. A cylindrical mirror body.

4 is an optical fiber inserted into a cylindrical mirror, 5 is a light source, and 6
7 is a light receiving section disposed at a predetermined position on one end side of the cylindrical mirror;
is an amplifier, and 8 is a voltmeter.

The reflective surface formed on the inner surface of the mirror body is preferably a regular reflective surface, but may also be a diffuse reflective surface. In order to make it a regular reflective surface, Ag * Aj' rAu, R is added to the inside of the glass tube.
h, (1!u, can be easily obtained by depositing a metal with high light reflectance such as Ti.

The metal forming the regular reflection surface may be any metal other than those mentioned above as long as it has a high reflectance with respect to the wavelength of the light source.

Further, it is possible to appropriately select and design an alloy tube or a plastic tube whose inner surface is plated with the above-mentioned metal, or an aluminum vapor-deposited film formed into a cylindrical shape so that the vapor-deposited surface is the inner surface. When using a transparent glass tube as the glass tube, a reflective surface can also be formed on the outer peripheral surface of the glass tube.

Furthermore, as a diffuse reflection surface used in the present invention.

It can be formed by applying a white paint that diffusely reflects light.

The reason why one cylindrical mirror body is used in the present invention is as follows.

This is because the maximum amount of light leakage 9 from the optical fiber 4 through which the light has passed is located at a position that makes a slight angle with the fiber axis.

This is because the cylindrical mirror body reflects and condenses leaked light from the optical fiber at a close distance.

That is, one cylindrical mirror body prevents leaked light from being diffused and focuses the light. Furthermore, it is effective to provide a light receiving section at a predetermined position of the cylindrical body to measure the amount of light leaked from the condensed light at one end. However, it goes without saying that it is also effective to provide a light receiving section in the middle of one cylindrical mirror body.

The mirror body used in the present invention is preferably a cylindrical mirror body as shown in FIG. 1, but any shape may be used as long as the cross section is cylindrical.
Even polygonal or elliptical shapes as shown in B) are effective.

Further, it is also possible to divide these cylindrical mirror bodies vertically into one part in order to clean the inside thereof.

Further, it is desirable that the cross-sectional area of the cylindrical part is constant in the longitudinal direction, but it can also be formed into a tapered shape. A light collecting section 10 made of a spherical nucleus having a reflective surface 6 inside is provided at a predetermined position on one end side, and a light receiving section 11 is provided on a part of the spherical nucleus.
This is the one with the .

It is effective to attach this spherical nucleus 10 to one end of the cylindrical mirror body. Furthermore, since there is a light-receiving part in a part of one bulb nucleus, when light enters from outside, it is difficult to distinguish it from light leakage from the fiber. Therefore, as shown in FIG. 2, it is preferable that the exit side of the fiber be formed with a cylindrical portion 12 having a diameter slightly larger than the fiber diameter, so that the structure can prevent external light from entering. Note that 16 is a black part for shielding light formed on the circumferential surface of the cylindrical part 12.

The spherical nucleus does not need to be a perfect sphere, and may have any shape as long as the same effect can be obtained.

In addition, the reflective surfaces formed on the inner surface of the spherical nucleus may be the same as those used for the mirror body, and in the example shown in FIG. is formed.

This spherical nucleus effect is effective when used to measure optical fibers with extremely small amounts of light leakage. The reason is the first
In a cylindrical mirror body as shown in the figure.

Although the light intensity is almost large at the center of the cylindrical body, since there is a fiber inside the cylindrical body, it is not possible to provide a light receiving section at the center.

For this reason, as shown in Figure 2, a spherical nucleus with a reflective surface inside is installed to reflect the light from approximately the center of the cylindrical mirror into the spherical nucleus, and a light receiving part provided in a part of the spherical nucleus is used. This is to detect light in the area.

The present invention will be specifically explained below using Examples.

Example 1 Inner diameter is 3.4 rrtm, 5 mm, thickness 1 ann
One cylindrical body was manufactured by applying silver mirror reaction, which is a customary custom processing, to the outside of a 1 m long glass tube to create a regular reflective surface, and having a light-shielding process on the outermost layer. The angle between the length direction of the cylindrical body and the light-receiving surface of the photodiode was set to 25, and a light-receiving section to which one photodiode was attached was provided avoiding the fiber. As shown in FIG. 1, the photodiode in the light receiving section was connected to an amplifier 7, and the output terminal of the photodiode was input to a voltmeter 8 to read the voltage and to measure the light intensity.

An optical fiber with a length of 3 m is passed through the cylindrical body of the device, and the light source is a HeNθ laser with an output of 1.5 mW and a luminous flux of 2 f.
Using a ffn optical fiber, the light enters at a distance of 2 degrees from one end of the optical fiber so that the light travels toward the light receiving section.

The voltage output on the voltmeter was read. The result is the first
Shown in the table.

According to the apparatus of the present invention, as shown in the table.

A light intensity of 20 to 40 mV can be easily obtained.

It has an excellent effect when condensing light leaking from an optical fiber.

Table 1 The following equipment was used.

Light source...Japan Science Engineering ■K
O-FS Photodiode...Hamamatsu Photonics ■S 1336
-8 BQ.

Voltmeter: Takeda Riken TR-6841 Example 2 A glass bulb with an inner diameter of 2 mm and a thickness of 1 mm is placed at one end of a glass tube with an inner diameter of 5 m and 10 mm, a thickness of 1 m, and a length of 20 ports. Attach the core, and as shown in Figure 2, attach a length of 60. Inner diameter 1.2mm, thickness lff1
A glass tube of size m was attached. For the longer glass tube and the spherical nucleus, a regular reflective surface was created on the inside as in Example 1, and for the shorter glass tube, the outermost layer was made without any processing in order to prevent light from entering from the outside. We fabricated a light condensing device by applying light blocking processing to the entire structure. A light receiving section was prepared above the spherical nucleus by attaching one photodiode to a glass tube having an internal diameter of 13 mm and having a regular reflective surface on the inside, and its output end was connected to an amplifier. Furthermore, the output terminal was input to a voltmeter so that the voltage could be read, and the amount of light was measured in the same manner as in Example 1.

The results are shown in Table M1. As can be seen from the table, the effect of the condensing device using the cylindrical mirror body having a spherical nucleus of the present invention is obvious, and it shows an extremely high light intensity, and the device incorporating the condensing device is well suited for practical use. is possible. In particular, it has an excellent effect when condensing light leakage from an optical fiber with a small amount of light leakage.

Example 3 A condensing device similar to Example 2 was manufactured, and a mixture of 20% white paint and 80% barium sulfate was applied only to the inner surface of the 9-bulb core to create a diffuse reflection surface. I tried the effect. The output end of the photodiode was connected to an amplifier, the output end was input to a voltmeter, and measurements were made in the same manner as in Examples 1 and 2. The results are shown in Table 1. As can be seen from the table, the condensing device consisting of a cylindrical mirror to which two spherical nuclei of the present invention were attached exhibited extremely high light intensity. It can be put to practical use even on a diffuse reflection surface, and is more effective when the required level of light collection is high.

〔Effect of the invention〕

Since the optical fiber side leakage light condensing device according to the present invention is configured as described above, the amount of light leakage from the side is greatly improved, the amount of light is large, and the measurement data is reliable. is obtained. Furthermore, according to the present invention, there is no need to bend the optical fiber at all, so the fiber characteristics are not affected, and by providing at least two light converging points, the optical transmission loss of the fiber can be easily measured. Become.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing one example of the present invention, FIG. 2 is a schematic sectional view showing another example of the present invention, and FIG.
B) is an example of a cross-sectional shape of a mirror that can be used in the present invention. 1: Cylindrical mirror body 3 = Reflection surface 4: Optical fiber 5: Light source 6: Light receiving section 7: Amplifier 8 Two voltmeters Patent applicant Azuma Shi Co., Ltd.

ζBn, slope' 3) Tsu? j Manabu Shiga, Commissioner of the Japan Patent Office, 1981, Indication of the case, Patent Application No. 251555, filed in 1982, 2, Name of the invention, Optical fiber side light leakage condensing device 3, Relationship with the amended person case Patent Application Envoy Office 2-2 Nihonbashi Muromachi, Chuo-ku, Tokyo Name
(315) Toshi Co., Ltd. 5, Number of inventions increased due to amendment None Full text amended specification 1, Title of invention Optical fiber side light leakage condensing device 2, Claims (11 Cylindrical shape with a reflective surface on the inside) An optical fiber side light leakage condensing device comprising a mirror body and a light receiving part provided at a predetermined position of the cylindrical mirror body. (2) The light receiving part is a spherical nucleus having a reflective surface inside. A side light leakage condensing device for an optical fiber according to claim (1), which is attached to a condensing section comprising a cylindrical mirror body. 3. Detailed description of the invention [Field of industrial application] This book The present invention relates to a device that efficiently collects light leakage from the side surface of an optical fiber. [Prior Art] Conventionally, attempts have been made to measure light leakage from the side surface of an optical fiber through which light has passed. For example, two A known method is to align two optical fibers in parallel or twist them together, enter light from one end of one optical fiber, and measure the light leaking to one end of the other fiber. In the case of this method, the light leakage itself is faint;
There was a problem that the amount of light was insufficient. Therefore, methods such as increasing the input optical power or increasing the length of the two optical fibers are considered, but if the fibers are long, measurement cannot be easily performed. There are limits. Furthermore, since bending the optical fiber slightly increases the amount of light leakage, there is also a method of locally bending the optical fiber. However, if only a part is bent, the amount of light will be insufficient and it will take some time.
+Not only does it require bending, but it also has drawbacks such as the equipment being complicated and the optical transmission characteristics of the optical fiber being affected later. That is, it is important to increase the amount of light leakage collected by a simple method while keeping the optical fiber in its natural shape. [Problems to be Solved by the Invention] The present inventors have developed an optical fiber side light leakage condensing device that does not have the above-mentioned drawbacks, especially a device that can condense a large amount of light from the side of the fiber without deforming the optical fiber. The present invention was arrived at as a result of intensive study. That is, one object of the present invention is to provide an optical fiber side light leakage condensing device with significantly improved light condensing efficiency. Means for Solving Problem C] An object of the present invention is to reduce side light leakage of an optical fiber consisting of a cylindrical mirror body having a reflective surface inside and a light receiving section provided at a predetermined position of the cylindrical mirror body. This is accomplished by a light concentrator. The details of the present invention will be explained below with reference to FIGS. 1 and 2. FIG. 1 illustrates an example of a side light leakage condensing device for an optical fiber according to the present invention. In FIG. A cylindrical mirror body with a reflective surface inside, 5'
is a reflective surface facing inward, 4 is an optical fiber inserted through the cylindrical mirror body 1, 5 is a light source, 6 is a light receiving section disposed at a predetermined position on one end of the cylindrical mirror body, 7 is an amplifier, 8 is a voltmeter. It is desirable that the reflective surface facing inward formed on the mirror body be a regular reflective surface, but it may also be a diffuse reflective surface.
It can be easily obtained by vapor depositing or coating a metal with high light reflectance such as Rh, Cu, or Ti. The metal forming the reflective surface may be any metal other than those listed above as long as it has a high reflectance for the wavelength of the light source.If a non-transparent tube such as a metal tube or plastic tube is used instead of a transparent glass tube, For this purpose, the inner surface may be plated or coated with the above-mentioned metal or the like. Of course, it goes without saying that the inner surface of the transparent glass tube may be a mirror surface. Furthermore, the metal tube itself is made of materials with high light reflectance, such as gold, silver, iron, and steel. For nickel, chromium, aluminum, and alloys thereof, the inner surface of the strip may be polished to a mirror surface. Further, it is possible to appropriately select and design a film in which aluminum is vapor-deposited into a cylindrical shape so that the vapor-deposited surface is the inner surface. Furthermore, as a diffuse reflection surface used in the present invention. It can be formed by coating the inner or outer surface with a white paint that diffusely reflects light. In the present invention, the reason why a cylindrical mirror body is used is that the maximum amount of light leakage 9 from the optical fiber 4 through which the light passes is located at a position that makes a slight angle with the fiber axis. For example, if a photodiode, phototube, photomultiplier, etc. are simply placed close to the fiber, the amount of light will be extremely small. Therefore, the purpose is to reflect leaked light from the optical fiber at a close distance and collect the light using the cylindrical mirror body. That is, one cylindrical mirror body prevents leaked light from being diffused and focuses the light. Furthermore, a light receiving section is provided at a predetermined position of the cylindrical mirror body to measure the amount of light leaked from the collected light. The predetermined position here means that the light receiving section is effectively provided at one end of the cylindrical mirror body. However, it goes without saying that it is also effective to provide a light receiving section in the middle of the cylindrical mirror body. The mirror body used in the present invention is preferably a cylindrical mirror body as shown in FIG. 1, but it may have any shape as long as it has a cylindrical cross section.
Even polygonal or elliptical shapes as shown in B) are effective. Moreover, it is also possible to vertically divide these cylindrical mirror bodies into nine parts for cleaning the inside. Furthermore, although it is desirable that the cross-sectional area of the cylindrical portion be constant in the longitudinal direction, it may also be formed into a tapered shape. Figure wc2 is a detailed explanation of the present invention, which is composed of a transparent glass bulb core 2' and a reflective surface forming layer 3 at a predetermined position on one end side of a cylindrical mirror body. A light condensing section 1o made of a spherical nucleus having an inward reflecting surface 6' is provided, and a light receiving section 6 is attached to a part of the spherical nucleus. It is effective to attach this spherical nucleus to one end of the cylindrical mirror body. Also, since there is a light-receiving part in a part of the nine bulbs, if light enters from outside, it is difficult to distinguish it from light leakage from the fiber. Therefore 1
As shown in the figure, the exit side of the fiber is formed with a glass tube 12 having a diameter slightly larger than the fiber diameter and smaller than the inner diameter of the cylindrical mirror body 1, and the outer peripheral surface of the glass tube 12 is coated with black paint 13 to allow external light to pass through. It is preferable to have a structure that prevents people from joining the party. Note that 13 is a black part for shielding light formed around the cylindrical part 12. The spherical nucleus does not need to be a perfect sphere, and may have any shape as long as the same effect can be obtained. The spherical nucleus may have a divided structure. Also, the inwardly facing reflective surface formed in the spherical nucleus. It may be the same as that used for the mirror body, and in the example shown in FIG. 2, a transparent glass tube 2. Transparent glass bulb core 7 and transparent glass tube 12
are integrally formed. This spherical nucleus effect is effective when used to measure optical fibers with extremely small amounts of light leakage. The reason is the first
In a cylindrical mirror body as shown in the figure. The light intensity is high at the center of the cylindrical mirror body, but since there is a fiber inside the cylindrical mirror body, it is not possible to provide a light receiving part in the stop part. For this reason, as shown in Figure 2, a spherical nucleus with a reflective surface inside is installed to reflect the light from approximately the center of the cylindrical mirror into the spherical nucleus, and a light receiving part provided in a part of the spherical nucleus is used. This is to detect light in the area. The present invention will be specifically explained below using Examples. Example 1 Inner diameter: 3.4 mm, 5 m, thickness: 1 mm, length: 11 mm
One cylindrical mirror body was fabricated by applying a silver mirror reaction, which is a normal mirror process, to the outside of the + transparent glass tube to create a reflective surface facing inward, and with a light-shielding process on the outermost layer. The angle between the length direction of the cylindrical mirror body and the light-receiving surface of the photodiode was set to 2A, and a light-receiving section with one photodiode attached was provided avoiding the fiber. As shown in FIG. 1, a device was manufactured in which the photodiode in the light receiving section was connected to an amplifier 7, and its output terminal was input to a voltmeter 8 to read the voltage and measure the light intensity. An optical fiber with a length of 3 m is passed through the cylindrical body of the device, and the light source is a HeNe laser, output 1.5 + nW, luminous flux 2 m.
The light enters at a distance of 2 degrees from one end of the optical fiber so that the light travels toward the light receiving section. The voltage output on the voltmeter was read. The result is the first
Shown in the table. As shown in the table, 9 according to the apparatus of the present invention. A light intensity of 20-40 mV can be easily obtained. It has an excellent effect when condensing light leaking from an optical fiber. Table 1 The following equipment was used. Light source - Nihon Kagaku Engineering ■NgO-2
8 Photodiode ~ Hamamatsu Photonics ■51556-8
8Q Voltmeter...Takeda Riken TR-6841 Example 2 One end of a transparent glass tube with an inner diameter of 5 am and 10 mm, thickness 1 ae, and a length of 20 mm, an inner diameter of 2 cm, and a thickness of 1 m.
Attach a transparent glass bulb core of
A glass tube with a thickness of 1 ml was attached. For the longer glass tube and the spherical nucleus, create a reflective surface facing inward as in Example 1, and for the shorter glass tube, to prevent light from entering from the outside, paint the outermost layer with black paint. We fabricated a light condensing device by applying light blocking processing to the entire structure. A light receiving section was made above the spherical nucleus by attaching one photodiode to a glass tube with an inner diameter of 13 mm, and its output end was connected to an amplifier. Furthermore, the output terminal was input to a voltmeter so that the voltage could be read, and the amount of light was measured in the same manner as in Example 1. The results are shown in Table 1. As can be seen from the table, the effect of the light condensing device using the cylindrical mirror body having a spherical nucleus according to the present invention is obvious, and it shows extremely high light intensity, and a device incorporating the light condensing device is sufficiently effective for practical use. It is possible. In particular, there is an excellent effect when condensing the leaked light of the optical 7-eyeper, which has a small amount of leaked light. Example 3 A condensing device similar to Example 2 was manufactured, and a mixture of 20 g of white paint and 80 g of barium sulfate was applied only to the inner surface of the core of the glass bulb to create a diffuse reflection surface facing inward. We tried the effect of different reflective surfaces. The output end of the photodiode was connected to an amplifier, the output end was input to a voltmeter, and measurements were made in the same manner as in Examples 1 and 2. The results are shown in Table 1. As can be seen from the table, the condensing device consisting of a cylindrical mirror to which the spherical nucleus of the present invention was attached exhibited extremely high light intensity. Practical use is also possible for diffuse reflection surfaces. [Effects of the Invention] Since the optical fiber side light leakage condensing device according to the present invention is configured as described above, the amount of light leakage from the side is greatly improved, and the amount of light is increased, so that measurement data cannot be reflected. You can get something reliable. Furthermore, according to the present invention, there is no need to bend the optical fiber at all, so it does not affect the fiber characteristics, and the optical transmission loss of the fiber can be easily measured by providing a small number of light focusing points (two points in each case). 4. Brief description of the drawings Fig. 1 is a schematic cross-sectional view showing one example of the present invention, Fig. 2 is a schematic cross-sectional view showing another example of the present invention, Fig. 3 (A), ( B)
1 illustrates an example of a cross-sectional shape of a mirror body that can be used in the present invention. 1: Cylindrical mirror body 2.12: Transparent glass tube 2/:
Transparent glass bulb core 3: Reflective surface forming layer 3/, reflective surface
4: Optical fiber 5: Light source 6:
Light receiving section 7: Amplifier 8: Voltmeter 9: Leakage light 10: Light collecting section Patent applicant Toshi Co., Ltd. g

Claims (2)

[Claims] (1) A side light leakage and condensing device for an optical fiber, comprising a cylindrical mirror body having a reflective surface inside and a light receiving section provided at a predetermined position of the cylindrical mirror body. (2) Side leakage light condensing of the optical fiber according to claim (1), wherein the light receiving section is attached to a cylindrical mirror body via a condensing section consisting of a spherical nucleus having a reflective surface on its inner surface. Device.