JPH1031130A - Ferrule for diagonal pc and its polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the eccentricity of a polishing surface in spite of a change in stock removal during the polishing of the end face of the ferrule for a diagonal PC. SOLUTION: The ferrule 60 for the diagonal PC is chamfered at its front end, and its chamfering angle is specified to 30 to 40 deg., for example, 35 deg.. The ferrule 60 for the diagonal PC is pressed at a prescribed angle of inclination onto the polishing sheet 53 of a polishing surface plate 51 and relative trochoid curvilinear motion is applied between the ferrule 60 for the diagonal PC and the polishing surface plate 51, by which the end face 61 of the ferrule 60 for the diagonal PC is formed gradually to a spherical surface. As a result, the eccentricity of the polishing surface is suppressed even if the stock removal changes during the polishing of the end face of the ferrule 60 for the diagonal PC. The spherical end face having the desired shape is thus formed on the ferrule. The ferrule with the high-performance optical fiber is thereby easily obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oblique PC ferrule and a method for polishing the same.

[0002]

2. Description of the Related Art An optical connector used in optical fiber communication is required to have a small insertion loss and a small amount of return light. At present, as an optical connector that most meets this requirement, the end face of the optical fiber held by the ferrule together with the ferrule end face is slanted with respect to a plane perpendicular to the axis of the optical fiber and polished to a convex spherical surface.
The optical connector called "C connector" is the most powerful.

The end face of this connector has been conventionally formed as follows. A conventional method will be described with reference to a conventional optical fiber end face polishing apparatus shown in FIG. In the apparatus for polishing an end face of an optical fiber shown in FIG. 5, 1 is a ferrule holding an optical fiber in a small through hole at the center of its axis, and 2 is a ferrule holding jig for holding the ferrule 1 by inwardly inclined by a standardized angle Θ. , 11 is a base, 3 is a polishing platen provided on the base 11, 4 is an elastic body stuck on the polishing platen 3, 5 is a polishing sheet stuck on the elastic body 4. . The polishing platen 3 rotates and revolves by a drive mechanism (not shown). The polishing platen 3 has a conical shape in which the angle formed by a plane perpendicular to the axis of rotation (rotation or revolution) from the outer periphery to the center and at right angles increases by a small angle Δ. The ferrule 1 is pressed against the polishing sheet 5 by a ferrule holding jig 2 forming a ferrule holding portion and a pressing shaft 40. The ferrule holding jig 2 is not rotated by the rotation of the polishing platen 3 by the support rod 41.

In the above-mentioned polishing apparatus, as shown in FIG. 6, the axis 1A of the ferrule 1 is inclined by an angle γ with respect to the surface of the polishing sheet 5, and passes through the axis 1A on the polishing surface of the ferrule 1 at this time. Assuming that the angle between the tangent and the axis 1A is β, γ does not coincide with β. This is because the polishing is performed using the chamfered ferrule.

[0005] This will be described with reference to FIG. The end face 1B of the polished ferrule 1 is convex, and its vertex A
Is the midpoint of the length D (M1 = M2). But,
Since the ferrule 1 has a chamfered portion, the point B at which the axis 1A of the ferrule 1 intersects with the convex surface does not become the center of the length D, and in this case, L ₁ <L ₂ . Therefore, B
The tangent at the point will have a difference of δ from the plane of the polishing sheet 5. Here, δ = β−γ.

[0006]

SUMMARY OF THE INVENTION To solve this problem,
Therefore, it is conceivable that the surface plate is previously inclined by δ. I
However, as shown in FIG. 8, δ becomes δ as polishing proceeds.
₁To δ_TwoOr become larger (in some cases smaller
The value of δ may change when the polishing amount changes.
It changes with it. Eccentricity increases when δ changes
As a result, gaps occur when connecting optical fibers,
The reflection and loss of optical signals due to the air layer caused by this
The problem of increase arises. A1 and A2 polished surface in the figure
N at the midpoint of _Two= N_Two'Also N₁= N₁'. sand
In other words, as the polishing progresses, the middle point of the polished surface becomes A₁From A
_TwoMove on to

SUMMARY OF THE INVENTION An object of the present invention is to provide a ferrule for oblique PC and a method for polishing the same, which can reduce the change in the value of δ.

[0008]

Means for Solving the Problems To solve the above problems, the inventor of the present invention has proposed that as the diameter D of the polishing surface increases as the polishing of the ferrule end surface progresses, the radius R of the concave portion of the polishing sheet increases. Focusing on the effect of suppressing the increase in the value of δ occurs, as the polishing of the ferrule end surface proceeds, to suppress the increase in δ, by setting the end face shape of the ferrule so that the diameter of the polished surface increases ,
Diagonal PC that keeps δ almost constant regardless of the amount of polishing
The present invention proposes an end face shape of a ferrule for use and a method of polishing a ferrule using the end face shape.

According to various experiments, as shown in FIG. 9, when the chamfer angle of the ferrule is 30 degrees or less, the vertex of the convex sphere moves to the 9 degrees side as polishing proceeds. That is, δ decreases. When the chamfer angle is 40 degrees or more, the vertex of the convex spherical surface moves to the 7 degrees side. That is, δ increases. It was confirmed that when the chamfer angle of the ferrule was set to a value within the range of 30 to 40 degrees, the change in δ due to the progress of polishing could be effectively suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a polishing method for polishing an end face of a ferrule for oblique PC according to the present invention. FIG.
Reference numeral 51 denotes a polishing platen, and a polishing sheet 53 is adhered on the polishing platen 51 via an elastic body 52. The polishing sheet 53 allows the end surface 6 of the oblique PC ferrule 60 to be fixed.
1 is polished to form a desired spherical shape. Therefore, the conventional polishing apparatus shown in FIG. 5 can be used as the polishing apparatus.

The oblique PC ferrule 60 has an unpolished oblique PC ferrule 60 as shown in FIG. 2, and its tip is chamfered.
In the present embodiment, the angle is 35 °. The ferrule 60 for oblique PC shown in FIG.
The end face 61 of the oblique PC ferrule 60 is gradually formed into a spherical surface by pressing it upward at a predetermined inclination angle γ to give a relative trochoid curve motion between the oblique PC ferrule 60 and the polishing platen 51.

In this case, at the beginning of polishing, as shown in FIG.
D1 of the polished surface 53A generated by pressing
Is small, and the radius R1 of the polished surface 53A is also small.

As the polishing proceeds, the diameter D2 of the polishing surface 53A becomes larger than D1 as shown in FIG.
Is also larger than R1. Here, since the chamfer angle of the oblique PC ferrule 60 is set to an appropriate value of 35 °, the increase in δ caused by the increase in the diameter D of the polished surface is caused by the increase in δ due to the increase in the radius R.
Is reduced very effectively by the action of reducing, after all, even if the polishing amount changes with the progress of polishing, δ
Is kept substantially constant.

Therefore, the eccentricity of the spherical portion of the end face of the ferrule due to the polishing can be extremely small, and the two oblique P ferrules when the oblique PC ferrule is connected can be suppressed.
The air gap generated between the end faces of the C ferrule can be eliminated, and the reflection and loss of the optical signal can be reduced. The end face shape of the ferrule that can expect such an effect is shown in FIG.
The chamfer angle is 30 ° ~
It was in the range of 40 °.

[0016]

According to the present invention, as described above, the oblique PC
During polishing of the end face of the ferrule for use, the eccentricity of the polished surface is suppressed even if the amount of polishing changes, and a spherical end face having a desired shape can be formed on the ferrule, so that a high-performance ferrule with an optical fiber can be easily obtained. Can be.

[Brief description of the drawings]

FIG. 1 is a view showing a polishing method when polishing an end surface of a ferrule for oblique PC according to the present invention.

FIG. 2 is a front view showing an unpolished state of a ferrule used for performing the polishing method shown in FIG. 1;

FIG. 3 is an explanatory diagram for explaining a state of a polished surface when the amount of polished ferrule is small in the ferrule polishing method shown in FIG. 1;

FIG. 4 is an explanatory diagram for explaining a state of a polished surface when a polishing amount of a ferrule is increased in the ferrule polishing method shown in FIG. 1;

FIG. 5 is a sectional view showing a conventional ferrule polishing apparatus.

FIG. 6 is an explanatory diagram for explaining the relationship between the inclination of the end face and the inclination angle of the ferrule when a conventional polishing method is used.

FIG. 7 is an explanatory diagram for explaining a state of displacement between the center of the ferrule and the center of the polished surface.

FIG. 8 is an explanatory diagram for explaining how a center of a polished surface changes according to a change in a polishing amount.

FIG. 9 is a diagram for explaining movement of a vertex of a convex spherical surface of a ferrule end surface.

[Explanation of symbols]

 52 Elastic body 53 Polishing sheet 53A Polishing surface 60 Ferrule for oblique PC 61 End face

Claims (2)

[Claims] 1. A ferrule for an oblique PC, wherein a ferrule for an oblique PC is provided with a chamfered portion at a tip portion, and an angle of the chamfered portion is set to a value within a range of 30 ° to 40 °. 2. The method for polishing an end face of a ferrule for an oblique PC according to claim 1, wherein the end face of the ferrule for an oblique PC is placed on a polishing sheet placed on an elastic body.
The end surface is formed into a convex spherical surface by relatively moving the polishing sheet and the oblique PC ferrule while pressing the ferrule for C so that the axis of the ferrule for C makes a predetermined angle with the perpendicular line formed on the plane of the polishing sheet. A method for polishing a ferrule for oblique PC, characterized in that: