JPH06118266A - Light terminal component - Google Patents

Abstract

PURPOSE:To easily insert a dielectric multi-layer film filter having the signal light transmission and test light cutoff/reflecting functions to an optical fiber and provide the stable optical characteristic regardless of the skill of a worker when the signal transmission and test are concurrently performed via multiple wavelengths. CONSTITUTION:A light terminal component inserted into a photo-connector adapter is constituted of a coupling sleeve 4 inserted from both sides with precision ferrules 3-1 holding bare fiber sections 2 at the terminals of an optical fiber, and a pair of insert members 5 arranged face to face between a pair of the ferrules 3-1 in the coupling sleeve 4 inserted with a bare fiber 8 at the center. A dielectric multi-layer film filter 6 is deposited on the connection face 9 of two insert members 5. The precision ferrules 3-5 are inserted from both sides into the coupling sleeve 4 arranged with the insert members 5 inside, and the adapter is merely connected to a plug, and the insertion and fixing of the filter 6 is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical terminal component used in the field of optical communication technology, and more particularly to a line end portion of an optical fiber in the case of simultaneously performing signal transmission and testing by wavelength division multiplexing.

[0002]

2. Description of the Related Art As the application of optical communication systems expands, it is necessary and is under study to establish a test monitoring technique for an optical line composed of optical fibers. For this purpose, it is necessary to test the characteristics change and deterioration state of the optical line in use, and as a realization means, a signal and a test light (hereinafter referred to as signal light and test light) are simultaneously obtained by wavelength multiplexing. A transmission method is about to be used.

When performing signal transmission and testing by wavelength division multiplexing, it is particularly necessary to suppress the influence of the test light on the signal light (for example, in the case of digital transmission, the power penalty in the code error rate). To this end, it is inevitable to insert an optical filter that blocks the test light and transmits the signal light. On the other hand, in order to determine whether the signal light reaches the end of the optical line, the test light is blocked and reflected by the optical filter, and the reflected light is analyzed by an optical pulse tester or the like. The detection method is effective.

Therefore, conventionally, a method of inserting a dielectric multilayer filter in which dielectric thin films are laminated into an optical fiber has been studied and put to practical use. FIG. 5 shows a cross-sectional view of a typical basic configuration example. This is to embed a dielectric multilayer filter inside the optical connector. The optical connector is a ferrule part 3 that is directly connected to an optical fiber terminal.
have.

The ferrule part 3 is a cylindrical precision ferrule 3 with good outer diameter dimensional accuracy, roundness, and cylindricity in which the bare fiber portion 2 of the optical fiber core wire 1 is inserted and fixed in the center hole.
-1, a collar tube 3-2 integrally attached to the rear end of the precision ferrule 3-1 and the collar tube 3-2.
And an adhesive 3-3 for fixing the optical fiber core wire 1 and the optical fiber core wire 1. The precision ferrule 3-1 is fitted into the sleeve A having a good inner diameter accuracy from both sides, and the adapter C holding the sleeve A is screwed with the plugs C engaging with the collar tube 3-2 from both sides. By this, the ferrule end faces are brought into contact with each other with high precision.

Such a configuration is well known as a general optical connector, and in the past, a collar tube 3-
After carving a groove 50 penetrating the bare fiber portion 2 in 2, the dielectric multilayer filter 51 is obliquely inserted into this groove 50 (by slightly inclining, reflection of test light is suppressed), Next, an optical adhesive 52 is filled in the void portion of the groove 50.

[0007]

However, in the conventional structure as described above, the collar tube 3-2 and the adhesive 3-
3. It is necessary to form the groove 50 penetrating the bare fiber portion 2, and the depth thereof reaches about 1 mm. Moreover, it is preferable that the width of the groove 50 is as small as possible in order to suppress an increase in loss due to the groove (the thickness of the dielectric multilayer filter 51 is generally about 30 to 50 μm.
The groove width of 0 is about 50 to 70 μm). It is difficult to form such a thin and deep groove in the ferrule part with a uniform width, and at present, the processing cost is most necessary.

Further, both the step of inserting the dielectric multilayer filter 51 into the groove 50 and the step of injecting the adhesive 52 have to rely on manual work, and the optical characteristics depend on the skill of the operator. Therefore, there is a problem in that the test light blocking characteristic and the reflection characteristic and the signal light transmitting characteristic cannot be stably realized. Therefore, it is an expensive part that is extremely poor in manufacturability.

The present invention has been made to solve the above problems, and an object thereof is to easily provide a dielectric multilayer filter having a function of transmitting a signal light and a test light blocking / reflecting to an optical fiber. An object of the present invention is to provide an optical terminal component that can be inserted and that can stably realize a filter function having excellent optical characteristics regardless of the skill of an operator.

[0010]

In order to achieve the above object, the present invention has the following constitution. That is, insert the optical terminal parts that are inserted inside the optical connector adapter that connects the optical connector plugs into each other, and the fitting sleeve into which the ferrule that holds the end of the optical fiber is inserted from both sides and the optical fiber. And a pair of nesting members facing each other between the pair of ferrules in the fitting sleeve, and a dielectric multilayer filter is vapor-deposited on the facing joint surfaces of the two nesting members. Further, it is preferable that the opposing joint surfaces of the two nesting members be slightly inclined with respect to the surface orthogonal to the optical fiber axis.
Moreover, the number of nesting members is not limited to two, and may be one. In this case, 1 between the pair of ferrules in the mating sleeve.
A plurality of nesting members are arranged, and a dielectric multilayer filter is vapor-deposited on the joining surface of one of the nesting members facing one ferrule. It is preferable that the joining surfaces of the nesting member and the ferrule facing each other are slightly inclined with respect to the surface orthogonal to the optical fiber axis, as described above.

[0011]

In the above-mentioned structure, two nesting members, each having a dielectric multilayer filter deposited on the opposing joint surfaces, are inserted into the central portion of the sleeve, and the ferrule is provided on both sides of the sleeve in the same manner as a general optical connector. The insertion of the dielectric multilayer film filter into the optical connector is completed simply by inserting it from and connecting it to the adapter with a plug. The filter can be created by simply depositing a dielectric multilayer film on the polished end face of the nesting member, and there is no need for a very mass-producible manufacturing process such as engraving grooves on the optical fiber or inserting filters into these small grooves. Becomes Further, the same effect can be obtained when the number of nesting members is one, but the number of parts can be reduced and
Since the connection end face of the ferrule is different on the side opposite to the dielectric multilayer film filter side, both ferrules cannot be connected without this nesting member, and there is an advantage that illegal use of an optical line can be prevented. Further, the dielectric multilayer filter transmits the signal light of wavelength λ ₁ and blocks and reflects the test light of wavelength λ ₂ , but by reflecting the test light slightly by tilting the facing surface of the nesting member. It is possible to suppress the amount of light and correspond to an optical pulse detector having high sensitivity.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an illustrated embodiment. It should be noted that the same or corresponding parts as in the conventional case are designated by the same reference numerals. 1 is a longitudinal sectional view showing a first embodiment of an optical terminal component of the present invention, FIG. 2 is a sectional view showing the assembling steps in order, FIG. 3 is an exploded perspective view thereof, and FIG. 4 is a second embodiment of the present invention. It is a longitudinal cross-sectional view showing an example.

[Embodiment 1] In FIG. 1, a ferrule portion 3 connected to an optical fiber core wire has an outer diameter dimension in which a bare fiber portion 2 of the optical fiber core wire 1 is inserted into a center hole as in the conventional case. A cylindrical precision ferrule 3-1 with good accuracy, roundness, and cylindricity, a collar tube 3-2 integrally attached to the rear end of the precision ferrule 3-1, and this collar tube 3- 2 and the optical fiber core wire 1 are fixed by an adhesive 3-3. The ferrule part 3 can use an existing one.

In contrast to the ferrule portion 3 as described above, the optical terminal component of this embodiment comprises a fitting sleeve 4, two nesting members 5, and a dielectric multilayer filter 6. The nesting member 5 is a cylindrical member having the same diameter as the precision ferrule 3-1 and the same outer diameter dimensional accuracy, roundness, and cylindricity, and the material thereof is also stainless steel, zirconia, or the like. An insertion hole 7 is bored in the central axis of such a nesting member 5, and a bare fiber 8 cut to a predetermined length is inserted and fixed in the insertion hole 7.

The facing surfaces of the pair of nesting members 5 are polished with a slight inclination with respect to the surface orthogonal to the optical fiber axis, and the dielectric multilayer filters 6 are vapor-deposited on the inclined surfaces 9, respectively. This dielectric multilayer filter 6 is
This is an interference film filter used in multiplexers, demultiplexers, etc.By appropriately selecting the material and number of layers of the dielectric film, the signal of wavelength λ ₁ is transmitted and the test light of wavelength λ ₂ is transmitted. It can be blocked / reflected. The joining surface of the nesting member 5 facing the precision ferrule 3-1 is polished to form the convex spherical surface 10 in the same manner as the convex spherical surface 11 of the precision ferrule 3-1.

The reason why the surface on which the dielectric multilayer film is deposited is the inclined surface 9 is to suppress the reflection of the test light. That is, the optical pulse tester used for detecting breakage of the optical fiber has high sensitivity, and if the dielectric multilayer filter 6 is arranged at right angles to the optical fiber axis, the amount of reflection becomes large, which is not preferable. On the other hand, in splicing a single mode optical fiber, in order to reduce reflected light, the splicing surface is inclined at 8 to 10 °.
Since the reflected light is also required to some extent, the inclination angle is set to about 2 °. The convex spherical surfaces 10 and 11 are used for joining optical fibers to each other, and by increasing the adhesion between the end faces, Fresnel reflection loss or the like at the joining surface can be reduced.

The fitting sleeve 4 is the same as the conventional fitting sleeve, although it is longer by the length of the nesting member 5.
A slit 4a parallel to the optical fiber axis is provided in a cylinder having an inner diameter slightly larger than the outer diameter of the precision ferrule or a cylinder having an inner diameter smaller than the precision ferrule (see FIG. 3) to reduce the connection error by the spring effect. Use one.

Next, the procedure for assembling the optical terminal component according to the first embodiment will be described (see FIGS. 2 and 3). (1) Nesting assembly The bare fiber 8 is inserted into the insertion hole 7 of the nesting member 5 which has been precisely processed. (2) Adhesion / Fixing The adhesive 12 is filled and then cured to fix the nesting member 5 and the bare fiber 8.

(3) Polishing One end face of the nesting member 5 is convexly spherically polished, and the other end face is obliquely polished to form the inclined surface 9 and the convex spherical surface 10. For this polishing, polishing equipment conventionally used for polishing optical connectors can be applied, and no special dedicated polishing device is required. (4) Vapor Deposition The dielectric multilayer filter 6 is vapor-deposited on the inclined surface 9 that has been obliquely polished. Since this process can be performed on 100 to 1000 nesting members 5 at the same time, the deposition cost per one is negligible.

(5) Assembly Using the optical adhesive 13, the pair of nesting members 5 are bonded together. (6) Insertion of fitting sleeve Insert the assembled pair of nesting members 5 into the center of the fitting (splitting) sleeve 4. At the time of connecting the optical fibers, the precision ferrule 3-1 is inserted from both sides of the fitting sleeve 4 containing the nesting member 5, and the plug is screwed to the adapter, and the connecting work is completed.

As described above, a large number of the pair of nesting members 5 can be manufactured at the same time, and the problem of mass productivity, which has been a conventional problem, can be solved. Furthermore, the angle of oblique polishing can be controlled with extremely high precision compared to the conventional one,
The crossing angle between the bare fiber 8 and the dielectric multilayer filter 6 can be kept constant. Therefore, the degree of dependence on the skill of the worker is less than in the conventional case. Moreover, without changing the ferrule part 3 of the existing optical connector,
The filter can be inserted and fixed in the optical fiber. It is necessary to use a new adapter.

When the signal transmission and the test were carried out by wavelength multiplexing using the optical terminal parts produced as described above, the transmission loss in the signal light (wavelength λ ₁ = 1310 nm) was 0.3 dB, and the test light (wavelength was At λ ₂ = 1550 nm, the transmission loss is 54 dB and the return loss is 10.4 dB.
Only the signal light was transmitted, and the reflection of the blocked test light could be suppressed to an appropriate value. The transmission loss of the signal light could be reduced to about half that of the conventional one.

[Embodiment 2] As shown in FIG. 4, one nesting member 5 is used. Although the shape and configuration of the nesting member 5 is exactly the same as that of the one nesting member of the first embodiment,
Precision Ferrule 3-1 'on Dielectric Multilayer Filter 6 Side
The slanted surface 9 of the nesting member 5 by obliquely polishing the joint end surface.
The inclined surface 14 corresponding to

With such a structure, the number of components can be reduced, and the assembly of (5) in the manufacturing process described above is not required, so that the assembly process can be simplified. Furthermore, since the pair of ferrules 3-1 to be connected have different joining end surfaces, they serve as an interface between the two connector members, and there is an advantage that illegal use of an optical line can be prevented.

[0025]

As described above, according to the present invention, the nesting member is arranged in the fitting sleeve into which the ferrule is fitted, and the dielectric multilayer filter is deposited on the end surface of the nesting member. It is extremely easy to insert and fix the filter required to block / reflect the test light.
Mass production will greatly reduce the processing cost of optical terminal parts. Further, a stable filter function can be realized regardless of the skill of the operator, and an optical terminal component having excellent optical characteristics such as transmission characteristics can be stably obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of an optical terminal component according to the present invention.

FIG. 2 is a vertical cross-sectional view sequentially showing an assembling process of the optical terminal component of FIG.

FIG. 3 is an exploded perspective view of the optical terminal component shown in FIG.

FIG. 4 is a vertical sectional view showing a second embodiment of the optical terminal component of the present invention.

FIG. 5 is a vertical cross-sectional view showing a conventional optical connector structure to which a filter function is added.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber core wire 2 Bare fiber 3 Ferrule part 3-1 Precision ferrule 3-1 'Oblique-polished precision ferrule 3-2 Collar tube 3-3 Adhesive 4 Fitting sleeve 5 Nesting member 6 Dielectric multilayer film filter 7 Insertion Hole 8 Bare Fiber 9 Inclined Surface 10, 11 Convex Spherical Surface 12 Adhesive 13 Optical Adhesive 14 Inclined Surface

Claims (4)

[Claims] 1. An optical terminal component to be inserted into an optical connector adapter for connecting optical connector plugs to each other, wherein a ferrule for holding an end of an optical fiber as a center is fitted from both sides, and an optical sleeve. The fiber comprises a pair of nesting members inserted in the center and facing each other between the pair of ferrules in the fitting sleeve,
An optical terminal component, characterized in that a dielectric multilayer filter is vapor-deposited on the opposing joint surfaces of these two nesting members. 2. The optical terminal component according to claim 1, wherein the facing joint surfaces of the two nesting members are inclined with respect to a surface orthogonal to the optical fiber axis. 3. An optical terminal component to be inserted into an optical connector adapter for connecting optical connector plugs to each other, wherein a ferrule for holding the end of an optical fiber at the center is fitted from both sides, and an optical sleeve. A fiber is inserted in the center of the fitting sleeve, and is formed between the pair of ferrules in the fitting sleeve. A nesting member is disposed between the pair of ferrules. Optical terminal parts characterized by being used. 4. The optical terminal component according to claim 3, wherein the facing surfaces of the nesting member and the ferrule are inclined with respect to the surface orthogonal to the optical fiber axis.