JPH0593822A - Polishing method and polishing device for coupled body of optical fiber and optical connector using fixed abrasive grains - Google Patents

Abstract

(57) [Abstract] [Purpose] The purpose is to polish the end face of a combined body of an optical fiber and an optical connector in a short time and with high accuracy. In a polishing method for polishing an end face of a combined body 20 of an optical fiber and an optical connector with fixed abrasives, a powder of cerium oxide, aluminum oxide, chromium oxide, or silicon oxide and a liquid bond are mixed. It is configured to include a step of polishing the end face of the combined body 20 with the accumulated liquid bond grindstone 29. Further, as a device used in this polishing method, a truing device 62 for correcting the polishing surface of the liquid bond grindstone 29 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method for polishing an end face of a combined body of an optical fiber and an optical connector with fixed abrasive grains, and a polishing apparatus used directly for carrying out this polishing method.

[0002]

2. Description of the Related Art In the case of detachably connecting an optical fiber, an optical connector is attached to the end of the optical fiber, and the end faces of the combined body thus formed are abutted against each other for connection. In this case, in order to accurately connect the optical fibers to each other, it is necessary to polish the end faces of the above-mentioned combined body. As a polishing method for polishing the end face of a combined body of an optical fiber and an optical connector with abrasive grains, various types of abrasive grains are placed on a buff or the like to polish the end face of the combined body. The polishing method based on how to use the abrasive grains is referred to as a free abrasive grain polishing method.

[0003]

However, when an optical fiber made of hard quartz glass like the above-mentioned combined body and an optical connector made of soft resin are polished together by a polishing method using free abrasive grains, a soft optical connector is obtained. Is more shaved and the end of the optical fiber is projected. Therefore, the end of this optical fiber is not necessarily polished flat, and in the case of a multi-core optical fiber bundle in which a plurality of optical fibers are bundled, the protruding length of the end of each optical fiber is different. There are many.

When the end portions are joined together by using the thus-polished joints, the end faces of the optical fibers do not come into direct contact with each other, resulting in a large connection loss, which adversely affects the transmission of optical signals. In addition, if the attachment and detachment of the coupled bodies is repeated, the end of the optical fiber may be damaged. Therefore, the end faces of the bonded body must be polished with high accuracy, but the polishing method using loose abrasive grains has a problem that the polishing time becomes long. In order to overcome the above-mentioned drawbacks of the polishing method using loose abrasive grains, it is necessary to perform polishing using a so-called fixed abrasive polishing method.

In this polishing method using fixed abrasive grains, since the grinding force is strong, the time required for polishing is reduced to a fraction, and the end of the optical fiber made of hard silica glass projects from the end of the optical connector. There is nothing to do. However, since the grinding force is strong as described above, polishing scratches, which are marks of polishing, remain on the end surface of the optical fiber after polishing. This flaw adversely affects the transmission of the optical signal.

Therefore, an object of the present invention is to polish an end face of a combined body of an optical fiber and an optical connector in a short time and with high precision.

In view of the above object, the present invention provides a polishing method for polishing an end face of a combined body of an optical fiber and an optical connector with fixed abrasive grains, which comprises cerium oxide,
An optical fiber and an optical connector, comprising a step of polishing an end face of the combined body with a liquid bond grindstone obtained by mixing powder of aluminum oxide, chromium oxide, or silicon oxide and a liquid bond. There is provided a method for polishing a bonded body of the above with fixed abrasive grains.

As a device used directly for carrying out this polishing method, a liquid bond grindstone made by mixing powder of cerium oxide, aluminum oxide, chromium oxide or silicon oxide and liquid bond is attached and rotated. And a holding device for holding the combined body so that the end face of the combined body of the optical fiber and the optical connector faces the polishing surface of the liquid bond grindstone attached to the grinding stone rotating device. A moving device capable of moving the relative position of the end surface of the combined body held by the holding device and the polishing surface of the liquid bond grindstone, and with respect to the polishing surface of the liquid bond grindstone attached to the grindstone rotating device. A polishing apparatus for a combined body of an optical fiber and an optical connector, comprising a truing device movable in a cutting direction and an in-plane direction of the polishing surface. To provide.

[0008]

According to the above-described polishing method, the polishing time is greatly shortened because the method uses fixed abrasive grains. Further, mechanical polishing between silica glass, which is a material of the optical fiber, and cerium oxide, aluminum oxide, chromium oxide, or silicon oxide and a chemical reaction induced by this mechanical energy (hereinafter referred to as mechanochemical reaction) As a result, the surface to be polished by the fixed abrasive grains at the tip of the optical fiber is melted, polishing scratches and work-affected layer disappear, and the surface becomes smooth.

According to the above polishing apparatus, the combination of the optical fiber and the optical connector is held by the holding device, and the combination is moved with respect to the polishing surface of the liquid bond grindstone attached to the grindstone rotation driving device. Is relatively moved and pressed by an appropriate pressure, and is abraded as the liquid bond grindstone is rotated by the operation of the grindstone rotation drive device. Since this liquid bond grindstone is very fragile, the region used for polishing not only polishes the bonded body that is the object to be ground, but, conversely, it is ground by this bonded body. A truing device is used to correct the unevenness of the polishing surface of the liquid-bonded grindstone that has been ground. The combined body held by the holding device can be moved by the moving device with respect to the new polishing surface of the liquid bond grindstone that is scraped and corrected by the truing device in this manner, and the liquid polishing wheel can be brought into contact with the new polishing surface.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on the embodiments shown in the accompanying drawings. First, referring to FIGS. 5 and 6, the optical connector 10 is an end portion of a tape-shaped multi-core optical fiber bundle 12 in which four optical fibers 14 made of quartz glass are aligned and integrated. A hole 10a for inserting the exposed portion of the fiber 14 is formed. The adhesive 16 is applied in the holes, the ends of the exposed tape-shaped multi-core optical fiber bundle are inserted and combined, and the combined body 20 shown in FIG. 6 is assembled. Then, in order to completely fix the four optical fibers 14 protruding from the tip surface 10b of the optical connector 10, the adhesive 16 is applied to the tip surface 10b of the optical connector 10.

A method of flattening the tip of the combined body will be described below. Since the optical connector 10 is made of plastic and the optical fiber 14 is made of quartz glass as described above, the hardness of the both is greatly different. Therefore, in the conventional polishing method using loose abrasive grains, the optical fiber 14 is moved to the end face 1 of the optical connector 10 by polishing the bonded body.
It projects from 0b. The experimental results that support this are shown in Figure 1.
2 shows. A diamond abrasive grain is placed on the buff to set a polishing rate V to 100 mm / sec, and a plastic material and a glass material are pressed under various pressing pressures P (gw / mm ² ) to obtain a polishing amount M (nm / nm / unit of time). sec) and the time t (sec) required to reach a predetermined polishing amount were measured.

From these results, it can be seen that the plastic materials and the glass materials have different polishing efficiencies, and the former is polished faster. On the other hand, FIG. 11 shows a result of an experiment in the case of the polishing method using the fixed abrasive grains of the diamond resin bond grindstone having the roughness of 2000, and the polishing speed V is 2000 mm / sec. In this case, the polishing efficiency of the plastic material and the glass material is the same. Therefore, the optical fiber 14 does not project from the end surface 10b of the optical connector 10. Further, for example, the pressing pressure P is 20 gw / mm
^As can be seen by comparing the cases of ² , the time t until reaching the predetermined polishing amount is shorter in the case of using fixed abrasive grains, and there is a difference of about 10 times.

Under the above preliminary experiment, in the present invention, the end face of the above-mentioned bonded body 20 is polished by a polishing method using fixed abrasive grains. First, as shown in FIG. 7, the end face of the coupling body 20 is ground by the diamond electrodeposition grindstone 22 in which the diamond 26 is electrodeposited on the surface of the metal plate 24, and the optical fiber 14 protruding from the end face 10b of the optical connector. Scrap off the end portion of the adhesive 16 and the adhesive 16. In the present specification, this grinding may also be referred to as polishing. This first polishing step has a roughness of 200.
A No. 0 diamond electrodeposition grindstone was used. Roughness is 1000
The number may be in the range from No. to 3000.

Next, a second polishing step for polishing the end faces of the combined body 20 is shown in FIG. In this process, the resin 32 is used as a bond and the diamond resin bond grindstone 28 in which the diamond abrasive grains 30 are bonded is used for polishing. In this second polishing step, a diamond resin bond grindstone with a roughness of 2000 was used. The roughness may be in the range of 1000 to 3000.

Further, in the third polishing step, the roughness is 400
The end face of the combined body is polished using a No. 0 diamond resin bond grindstone as in the second polishing step. Roughness is 3000
The number may be in the range from No. to 5000.

As a fourth polishing step, cerium oxide (Ce
The end face of the bonded body is polished by a liquid bond grindstone having a high density and low bonding force characteristic, which is obtained by mixing powder of O ₂ ) and liquid bond. Unlike the third polishing step, this polishing step can eliminate the polishing scratches in the third polishing step on the tip end surface of the optical fiber due to the mechanochemical reaction described above.

By this mechanochemical reaction, the conjugate 2
The end surface of 0 can be polished and finished with high precision. The roughness of the cerium oxide powder used in the fourth polishing step is 700.
Although it is 0, it may be in the range of 3000 to 10000.

The method of determining the polishing conditions in each of the above polishing steps will be described by taking the third polishing step as an example. Figure 9
When the polishing rate V is 1000 mm / sec, the pressing pressure P of the bonded body 20 to the diamond resin bond grindstone is P.
And the surface roughness Ra of the polished end face of the bonded body. The target surface roughness Ra in the third polishing step is 0.0
5 (μm), for example, with a diamond resin bond grindstone with a roughness of 4000, the pressing pressure P is 30 g.
It must be less than w / mm ² .

FIG. 10 shows the relationship between the pressing pressure P and the polishing efficiency M. The target polishing efficiency M in the third step is 50 nm / sec, and the polishing rate V is 100.
In the case of 0 mm / sec, the target value Pa = 0.05, M
= 50 nm / sec is not achieved. Polishing speed V is 20
In the case of 00 mm / sec, the pressing pressure P is 26 g with a diamond resin bond grindstone having a roughness of 4000.
If w / mm ² or more, polishing efficiency M is 50 nm / sec
The above is achieved. The polishing conditions for the third step were set as described above. Polishing conditions are similarly set in the other steps.

In the following, a polishing apparatus used for carrying out the above-described polishing method will be described with reference to FIGS. 1 and 2. A column 42 is erected on the rear part of the machine base 40, and a polishing grindstone (a liquid bond grindstone in this case) 29 is attached to the upper part of the column 42, and the liquid bond grindstone 29 is attached to a spindle having a horizontal axis by a motor M1. A grindstone rotation drive device 52 that rotates as a center is provided.

In front of the column 42, there is a front-back direction Z.
A linear guide 44 extending in the direction is fixed to the machine base 40. A slider 46 is attached on the guide 44 and can move on the linear guide 44. Further, on the slider 46, a saddle 4 which is movable in the left-right direction X direction via a linear guide 47.
8 is attached. A holding device 50 holding the combined body 20 is fixed on the saddle 48.

A motor M2 is attached at an appropriate height position of a fixing member 74 which is erected on the machine base 40,
The pinion gear 70 is fixed to the tip of the output shaft. On the other hand, a rack 72 is fixed on the holding device 50 so as to mesh with the pinion gear 70.

When the piston of the cylinder-piston device 56 mounted at the height position of the saddle 48 from the machine base 40 projects forward, the saddle 48 is moved forward in the Z direction together with the slider 46. Conjugate 2 at this position
The holding device 50 holds 0. After the holding work, when the piston is retracted, the saddle 48 can freely move in the Z direction together with the slider 46.

A weight 58 acts on the holding device 70, and when the piton moves backward as described above, it moves rearward in the Z direction together with the slider 46, and the tip end surface of the combined body 20 holds the liquid bond grindstone 29. The weight 58 is pressed against the polishing surface with a pressure corresponding to the weight of the weight 58. The pressing pressure may be adjusted by adjusting the position of the slider 46 in the Z direction instead of the weight.

Since the liquid bond grindstone 29 has a low bonding force characteristic as described above, when the bonded body 20 is polished, the polishing region is recessed by the bonded body. Therefore, it is necessary to correct the polishing surface of the liquid bond grindstone 29. Hereinafter, an apparatus for that purpose will be described. A Y-direction guide 66 capable of moving the L-shaped member mounting base 68 in the vertical Y direction by the motor M4 is mounted on the upper portion of the column 42. The Y-direction guide 66 is attached to the Z-direction guide 64 so as to be movable in the Z-direction by the motor M3.

An L-shaped member 60 having a truing tool 62 attached to the tip thereof is fixed to the L-shaped member mounting base 68. The Z direction guide 64 moves the truing tool 62 in the thickness direction of the liquid bond grindstone 29 to adjust the cutting depth, and the Y direction guide 66 controls the truing tool 62.
Can be moved inward of the polishing surface of the liquid bond grindstone 29 to correct the entire polishing surface to a flat surface.

Reference numeral 54 indicates a working fluid unit, which supplies the working fluid to the polishing surface during polishing of the combined body 20. Water was used as the processing liquid. The polishing apparatus described above has been described for the liquid bond grindstone in the fourth polishing step in the polishing method of the present invention, but it can be used in each of the first to third steps, and in the actual polishing operation, the above polishing can be performed. Four devices are lined up and each device is assigned to each process.

Next, the polishing method will be described in detail with reference to FIGS. 3 and 4. FIG. 3 corresponds to a view of the polishing grindstone 29 and the combined body 20 as seen from the direction B of FIG. The combined body 20 is held by the holding device 50, and by the action of the rack 72 and the pinion gear 70, the position 20A and the position 2 shown in FIG.
Linearly move L in the X direction between 0C. The motor M2 is controlled to reciprocate between them. During this time, the grinding wheel 29 is rotating about the central axis 52C. Therefore, the region between the circles L1 and L2 on the polishing surface of the polishing grindstone 29 is effectively used as the polishing region.

Further, as shown in FIG. 3, since the grinding wheel 29 rotates and the combined body 20 moves linearly, the polishing direction when the tip end surface of the combined body 20 is at the position 20A is the line L2 shown in FIG. And the polishing direction at the position 20C is the direction indicated by the broken line L3. That is, the polishing direction gradually changes during this period. When the angle θ shown in FIG. 3 is 45 degrees, the polishing directions L2 and L3 shown in FIG. 4 are orthogonal to each other. This is preferable as a polishing method.

The above explanation is about the polishing of the end face of the combined body of the tape-shaped multi-core optical fiber bundle and the optical connector.
The same applies to a combination of a single-core optical fiber and an optical connector. Further, aluminum oxide, chromium oxide, or silicon oxide may be used instead of cerium oxide in the above examples.

[0031]

As is apparent from the above description, according to the present invention, since the polishing method uses fixed abrasive grains, the polishing time is considerably shortened and the end portion of the optical fiber projects from the end face of the optical connector. There is nothing to do. Further, since a liquid bond grindstone of cerium oxide, aluminum oxide, chromium oxide, or silicon oxide is used, polishing scratches do not remain on the end face of the optical fiber, and polishing can be performed with high precision. Further, according to the present polishing apparatus, since the apparatus itself is equipped with the dresser for the polishing grindstone, the polishing work proceeds smoothly.

[Brief description of drawings]

FIG. 1 is a side view of a polishing apparatus according to the present invention.

2 is a front view of a rack and a pinion gear taken along the line BB in FIG.

FIG. 3 is an explanatory diagram of a method for polishing a combined body by the polishing apparatus of FIG.

FIG. 4 is an explanatory diagram of a result of polishing the end faces of the combined body by the polishing method shown in FIG.

FIG. 5 is a plan view showing a state in which an optical fiber and an optical connector are individually manufactured.

FIG. 6 is a plan view of a combined body of an optical fiber and an optical connector.

FIG. 7 is an explanatory diagram of a first-stage polishing process according to the present invention for the combined body of FIG. 6;

FIG. 8 is an explanatory view of a second step and a third step of polishing the combined body of FIG. 6 according to the present invention.

FIG. 9 is a result of preliminary experiments relating to determination of polishing conditions, and is a graph showing a relationship between pressing force and surface roughness.

FIG. 10 is a result of preliminary experiments relating to determination of polishing conditions, and is a graph showing a relationship between pressing force and polishing efficiency.

FIG. 11 is a graph showing the results of preliminary experiments in the polishing method using fixed abrasives according to the present invention.

FIG. 12 is a graph showing the results of preliminary experiments in a polishing method using loose abrasive grains.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Optical connector 12 Tape-shaped multi-core optical fiber bundle 14 Optical fiber 16 Adhesive 20 Combined body 22 Electrodeposition grindstone 28 Diamond resin bond grindstone 29 Liquid bond grindstone

Claims (4)

[Claims] 1. A polishing method for polishing an end face of a combined body of an optical fiber and an optical connector with fixed abrasive grains by mixing powder of cerium oxide, aluminum oxide, chromium oxide, or silicon oxide with a liquid bond. A method of polishing a fixed body of a bonded body of an optical fiber and an optical connector, comprising a step of polishing an end face of the bonded body with a firm liquid bond grindstone. 2. In the polishing method using the fixed abrasive,
The polishing grindstone is rotated and used, and the combined body is linearly moved within the plane of the polishing surface while pressing the combined body against the polishing surface of the rotating polishing grindstone.
A method of polishing a combined body of an optical fiber and an optical connector according to claim 1 with fixed abrasive grains. 3. A grindstone rotation drive device for mounting and rotating a liquid bond grindstone made by mixing powder of cerium oxide, aluminum oxide, chromium oxide, or silicon oxide and a liquid bond, an optical fiber and an optical connector. And a holding device for holding the combined body so that the end surface of the combined body faces the polishing surface of the liquid bond grindstone attached to the grindstone rotating device, and the end surface of the combined body held by the holding device. A moving device capable of moving the relative position of the liquid bond grindstone to the polishing surface, and a cutting direction and an in-plane direction of the polishing surface of the liquid bond grindstone attached to the grindstone rotating device. A polishing device for a combined optical fiber and optical connector, comprising a movable truing device. 4. A first linear guide for moving the holding device holding the combined body linearly within a polishing surface of a liquid bond grindstone attached to the grindstone rotating device, and the moving device with respect to the grind surface. 4. A polishing apparatus for a combined body of an optical fiber and an optical connector according to claim 3, further comprising a second linear guide that linearly moves in a cutting direction.