JP3237728B2 - Multi-core optical fiber cable splicer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection device for connecting optical fibers at a time based on a multi-core collective V-groove method, and more particularly, to a multi-core collective device having an axial alignment mechanism for individual cores. The present invention relates to a connecting device (multi-core optical fiber connecting device).

[0002]

2. Description of the Related Art When connecting optical fibers, it is necessary that the cores of the two optical fibers to be connected exactly match each other. If there is a core misalignment at the connection point, bending between the optical fibers, or a difference in the core diameter or relative refractive index difference between the connected fibers, a large loss occurs at the connection point.

[0003] In order to achieve low-loss connection in optical fiber connection, it is important to obtain a good cut surface and to minimize the axial deviation. Regarding the latter point, several alignment methods are known in order to make the alignment accurate. Among them, the most frequently used is a V that can be connected with low loss by using a simple jig.
This is a bonding method called a groove method. That is, in this method, two optical fiber end faces are set in a V-groove substrate by abutting each other, the optical fibers are pressed from above to perform axis alignment, and then connection by an adhesive or connection by fusion is performed.

The above-mentioned V-groove method can also be applied to a tape core in which a plurality of optical fibers are collectively coated to increase the density of the core. A schematic configuration of a conventional multi-core optical fiber connecting device for performing multi-core batch connection based on the V-groove method will be described with reference to FIG.

In FIG. 12, reference numeral 1 denotes an optical fiber ribbon in which a number of optical fibers 1a are bundled, 2 is a fine moving table, 3 is a clamp member, 4 is a V-groove table, and 5 is a fusing means. . In this figure, the respective components are arranged so as to be symmetric (symmetrical in the drawing) across the melting means 5. A method for connecting two optical fibers using the multi-core optical fiber connecting device having such a configuration will be briefly described below.

[0006] The covering member on the distal end side of the two optical fiber ribbons 1 is peeled off to expose the optical fiber 1a. The optical fiber ribbon 1 is disposed on two fine movement tables 2 arranged symmetrically and facing each other, and is pressed and fixed by the clamp means 3. The clamping means 3 has a hard clamp 3a and a soft clamp 3b. The latter clamp portion 3b presses the vicinity of the tip of the optical fiber 1a guided to the V groove of the V groove base 4. Next, by rotating the micrometer 2a provided on the fine moving table 2,
Is moved back and forth as shown by the arrow A, and the ends of the two optical fibers 1a are brought close to and opposed to each other by a predetermined distance.
Then, the both end portions that are close to each other are melted by the melting means 5 (movable up and down.
Fused by arrow B). By this melting, the tips of the two optical fibers 1 are welded.

In order to prevent axial displacement at the portion where the two optical fibers 1a are connected, two V-grooves symmetrically arranged on the plane of FIG. 12 are formed so that their dimensions are equal to each other. And must be accurately aligned with each other. However, in practice, there is a limit in increasing the precision of the dimension and the alignment of the V-groove, and an axis deviation error easily occurs in the optical fiber 1a. Even if a V-groove can be manufactured with high precision, it is difficult to perform high-precision axis alignment due to the eccentricity of the core of the optical fiber that occurs during the manufacturing process of the optical fiber and dust attached between the V-groove and the optical fiber. Becomes The axial misalignment in the core caused by these causes is the largest factor affecting the connection loss.

FIG. 13 shows the relationship between the amount of axis deviation (μm) and the loss due to axis deviation (dB).

The optical fiber is generally a graded multimode optical fiber having a core diameter of 50 μm and a core having a core diameter of several μm.
And a single-mode optical fiber. In the case of a multi-core connection of graded-type multi-mode optical fibers, a certain degree of axis deviation error is allowed because the core diameter is relatively large. Therefore, the connection loss can be suppressed to 0.1 dB or less even when the shaft alignment is performed only with the V-groove described above. However, since the core diameter of a single-mode optical fiber is several μm, as shown in FIG. 13, the connection loss due to misalignment is much larger than that of a graded-type multimode optical fiber. Is 2 μm, the theoretical loss in the case of the corresponding graded-type multimode fiber is very small at 0.066 dB, whereas the theoretical loss is 2 dB in the case of the single-mode optical fiber. Become larger. Therefore, in order to reduce the connection loss of the single mode optical fiber to 0.1 dB or less, it is necessary to suppress the amount of axial deviation to 0.49 μm or less. This limitation of the axis deviation cannot realize the axis alignment only by the guide of the V-groove, but the axis alignment mechanism (axis) in which the optical fibers of the multi-core optical fiber ribbon are individually aligned. Alignment mechanism) is required.

FIGS. 14 and 15 show examples of a high-precision axis aligning mechanism which has been used for single-core connection of a conventional single-mode optical fiber. FIG. 14 is of the stress-strain type, while FIG. 15 is of the lever type.

In either case, the cantilever 6 or the lever 7 is moved by fine movement of the micrometer 8 driven by a motor (not shown), and the V supporting the optical fiber 1a.
The groove base 4 is finely moved two-dimensionally (in the X and Y directions in the figure) to perform axis alignment. Reference numeral 9 denotes a coil spring for buffering.

[0012]

However, the following problems arise when attempting to perform axis alignment at the time of multi-core connection using the above-described single-axis connection axis alignment mechanism.

(I) It is necessary to provide two cantilever beams (or levers), two micrometers and two driving sources (motors) in accordance with the number of optical fibers. For example, in the case of an optical fiber ribbon consisting of 10 optical fibers having an interval of about 0.25 mm, 20 micrometers or the like are required, and it is extremely difficult to construct the above configuration in a space having only such an interval. is there.

(Ii) If dust or the like is present between the V-groove and the optical fiber, high-precision axial alignment is hindered. In order to reduce the influence of dust and the like, a very compact individual axis aligning mechanism is required, but it is difficult because of the above (i).

Therefore, an object of the present invention is to solve the above-mentioned problems and to make each optical fiber core extremely compact and unaffected by dust and the like existing between the optical fiber and a V-groove supporting the optical fiber. An object of the present invention is to provide a connection device for a multi-core optical fiber that can independently and precisely align the axes.

[0016]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a multi-core optical fiber connecting device according to the present invention is provided with a base, and provided on the base and symmetrical about a melting means. In a connecting device for performing multi-core batch connection of a plurality of optical fibers constituting a multi-core optical fiber core wire based on a multi-core batch V-groove method, comprising a group of two members having the same configuration arranged, The member group is disposed so as to be adjacent to and communicate with the V-shaped groove, and a V-groove substrate formed with a plurality of V-shaped grooves for individually holding a plurality of optical fibers, and A plurality of fine adjustment plates formed with a single-core holding groove for supporting the vicinity of the distal end of the optical fiber protruding from one end, and the fine adjustment plates are swingably supported and fixed on the base. Slidably connected to a plurality of substrate supports and a fine adjustment plate, and A plurality of piezoelectric fine adjustment members for finely moving the optical fiber on a two-dimensional plane orthogonal to the central axis of the optical fiber by finely moving the fine adjustment plate, and the fine adjustment plate and the fine adjustment member are slidably connected to each other. A member for
An axis deviation measuring member for measuring the axis deviation of the optical fiber, and a drive control member for driving the piezoelectric adjustment member based on the axis deviation measured by the axis deviation measuring member are provided. It is characterized by having.

[0017]

The plurality of optical fibers are individually held by the plurality of V-shaped grooves. In addition, the optical fibers individually held are placed in a single-core holding groove arranged so that the vicinity of the distal end thereof is adjacent to and communicates with the V-shaped groove, and the axial alignment with the opposing optical fiber is aligned. This is performed by the piezoelectric fine adjustment member and the drive control member. When the axes of the optical fibers are aligned with each other, the tip of the optical fiber is melted by the melting means and connected to the tip of the opposing optical fiber.

[0018]

1 and 2 show an embodiment of a multi-core optical fiber connecting device according to the present invention. The apparatus shown in these figures is for connecting optical fibers based on the V-groove method, similarly to the apparatus shown in FIG. 12 as a conventional example, and is used for fusion-connecting both optical fibers. The means and the means for bringing both optical fibers close to each other are the same as the conventional one.

FIG. 1 is a front view for explaining a schematic configuration of a multi-core optical fiber connecting device according to the present invention, and FIG. 2 is a side view thereof.

In FIG. 1, X, Y and Z are coordinate systems set for convenience in describing the apparatus of the present embodiment.
Each is orthogonal to the other, with the Z axis extending in a direction perpendicular to the plane of FIG. 1 and the X axis extending in a direction perpendicular to the plane of FIG.

This multi-core optical fiber cable connecting device has a V-shaped groove 10 for supporting the optical fiber 1a in the Z-axis direction.
a formed V-groove substrate 10, base 11, and base 1
A substrate support portion 12 interposed between the V-groove substrate 1 and the V-groove substrate 10 for fixing and supporting the V-groove substrate 10, a main body supported at the substrate support portion at one end so as to be swingable and bent in an L-shape A plurality of fine adjustment plates (optical fiber support members) 13 and a plurality of piezoelectric fine adjustment members 14 are formed.

The fine adjustment plate 13 formed in a substantially L-shape
At the top end, there is a V-shaped groove (single-core holding groove) 13a formed to match the inclination of the inner wall of the V-shaped groove 10a.
Since the single-core holding groove 13a slightly moves along the X-axis and Y-axis directions, no slippage (movement in the Z-axis direction) occurs between the single-core holding groove 13a and the optical fiber. Therefore, even if dust or the like is interposed between the V-groove and the optical fiber, the dust is less likely to be affected.

In the apparatus of this embodiment, four fine adjustment plates 13 are arranged in parallel. Each fine adjustment plate 13 is mounted on the substrate support 1.
2 is rotatably supported by the support pin 12a near the upper end.

FIG. 3 is a schematic side view for explaining a schematic configuration of four fine adjustment plates 13 provided in the apparatus of this embodiment. FIG. 4 is a schematic front view of the fine adjustment plate 13.

As shown in FIGS. 3 and 4, the fine adjustment plate 13 has a portion that contacts the optical fiber (a portion where the single core groove 13a is formed), an arm 13b that supports the V-groove substrate, and
It is composed of a projection 13c provided on the back surface of the arm 13b, and a member 13d having a rectangular bottom surface adhered to the end of the projection 13c and having a triangular front shape. The arrangement position of the protrusion 13c differs depending on the fine adjustment plate 13.

Also, as shown in FIGS. 1 and 2, the piezoelectric fine adjustment members 14 are individually provided on the respective fine adjustment plates 13, so that the individual piezoelectric fine adjustment members 14 will be described later. By finely adjusting the fine adjustment plates 13 individually, it is possible to make fine adjustments so that the tips of the optical fibers 1a maintain a good fusion posture.

FIG. 5 is a view for explaining the configuration of the piezoelectric fine adjustment member 14. As shown in FIG.

The piezoelectric fine adjustment member 14 is composed of two columns erected on the base 11 and symmetrically arranged.
Each pillar is a piezoelectric element 16a or 16b fixedly supported on the base 11, and a member 15a having a pyramid-shaped tip portion placed on the piezoelectric element 16a or 16b and having a bottom surface and a side surface forming a right angle. 15b. Member 15a
The V-shaped support portion is formed by placing the and the member 15b with their slopes facing each other.

Then, an inverted triangular member 13d is placed at the center of the tip (the above-mentioned support portion) of the pair of piezoelectric fine adjustment members 14 configured as described above. The two are not fixed and are in a sliding condition. Inverted triangular member 13d and member 1 attached to the tip of both voltage elements 16d, 16d
A wedge-shaped mechanism is formed between 5a and 15b. As shown in FIG. 2, a spring 17 is mounted between the fine adjustment plate 13 and the base 11, and the fine adjustment plate 13 and the member 13d receive a downward force by this spring to perform piezoelectric fine adjustment. It is pressed by the members 15a and 15b on the member 14.

When a voltage is applied to the piezoelectric element, the piezoelectric element 16
a, 16b are expanded and contracted. Thereby, the support member 13
The upper optical fiber 1a slightly moves, and the axis alignment operation becomes possible. Also. Here, the space is kept between the fine adjustment plates 13, but in reality there is almost no gap, and each of the V-groove substrates 1 and each piezoelectric fine adjustment member 14 are provided.
The grooves are arranged in a form corresponding to the zero V-shaped groove 10a. Further, each piezoelectric fine adjustment member 14 is arranged corresponding to each fine adjustment plate 13, and depends on the arrangement interval of the optical fibers 1a.
It is fixed in parallel on the base 11 with a slight offset. By employing such an axis alignment mechanism, the piezoelectric elements can be arranged very densely, and the axis alignment mechanism can be realized in a very compact manner.

Hereinafter, a method of axial tuning using the above-described apparatus will be described with reference to FIGS. In this embodiment, it is assumed that a bias voltage is applied to both the piezoelectric elements 16a and 16b in the extending direction (the direction of the arrow in the drawing) in the initial state. (In addition, in these figures, the dotted line indicates the position before the movement.) Therefore, as shown in FIG.
Optical fiber 1a held in the single-core holding groove 13a
Is slightly moved upward (in the direction of the arrow), a voltage is applied so as to extend both piezoelectric elements 16a and 16b.
When moving the piezoelectric element 16a downward as shown in FIG. 7, the bias voltage may be controlled so as to contract both piezoelectric elements 16a and 16b.

Also, as shown in FIG. 8 when moving slightly upward to the upper right, and as shown in FIG. 9 when moving slightly upward to the upper left, as shown in FIG.
b is operated. In the case of lateral movement, the voltage applied to both piezoelectric elements 16a and 16b is controlled so that one piezoelectric element 16b is contracted and the other piezoelectric element 16a is extended as shown in FIG. In this manner, the end (see FIGS. 1 and 2) on the side where the individual optical fibers 1a supported by the V-groove substrate 10 are to be fused is placed within a plane perpendicular to the central axis of the optical fiber. Axial alignment can be performed by finely moving it dimensionally (in a direction along the X or Y axis).

FIG. 11 shows an example of the configuration of a control circuit for aligning the axes of the optical fibers 1a using the multi-core optical fiber connecting device having such a configuration. Here, for simplicity of explanation, members not directly related to control are omitted. In FIG. 11, reference numeral 31 denotes an axis deviation measuring device for measuring the amount of axial deviation between end faces of optical fibers facing each other, and 32 denotes a well-known PID based on the amount of axis deviation inputted from the axis deviation measuring device 31. This is a controller that causes the operation amplifier (amplifier) 33 to generate an amplifier drive power supply corresponding to an appropriate fine movement amount for each optical fiber 1a by control or the like.

As the above-mentioned axis deviation amount measuring apparatus, there are a combination of an ITV television and an image processing system, and a means for minimizing the axis deviation by the maximum value of the power passing through the core of the optical fiber 1a to be connected. Conceivable. In addition, a method of monitoring an image of transmitted light from two opposite directions to an optical fiber held at an opposite position by a TV camera and performing image processing to obtain an axis shift amount is used. Is also good.

In a state where the end faces of the opposing optical fibers are brought close to each other and positioned near the fusion, the amount of axial misalignment between both optical fiber tips is measured by an axial misalignment measuring device, and the axial misalignment is measured. If the amount is not so large, it is possible to achieve the purpose only by holding one of the core wires with a normal V-groove and operating only one device.

If the initial axial deviation is relatively large, first, one of the bases is finely adjusted so that the sum of the two values of the axial deviations of all the core wires is minimized. In advance, the control may be performed by driving only the piezoelectric element of one of the bases or by slightly moving the piezoelectric elements of both bases facing each other.

When the amount of axis deviation is obtained as described above, the amount of axis deviation is input to a controller, an amplifier drive voltage is generated by a controller such as a PID, and this is input to an amplifier. An element drive voltage is applied to each piezoelectric element. By repeating this loop, the amount of axis deviation can be made substantially zero.

[0038]

As described above, the multi-core optical fiber connecting device according to the present invention has a base and the same structure provided on the base and arranged symmetrically about the melting means. A connection device for performing multi-core batch connection of a plurality of optical fibers constituting a multi-core optical fiber core wire based on a multi-core batch V-groove method, comprising:
The member group is arranged so as to be adjacent to and communicate with the V-shaped groove, and a V-groove substrate formed with a plurality of V-shaped grooves for individually holding a plurality of optical fibers, and A plurality of fine adjustment plates formed with a single-core holding groove for supporting the vicinity of the distal end of the optical fiber protruding from one end, and the fine adjustment plates are swingably supported and fixed on the base. A plurality of substrate supports and a plurality of piezoelectric elements which are slidably connected to the fine adjustment plate, and finely move the fine adjustment plate to finely move the optical fiber on a two-dimensional plane orthogonal to the central axis of the optical fiber; A fine adjustment member, a member for slidably connecting the fine adjustment plate and the fine adjustment member, an axis shift amount measurement member for measuring the axis shift amount of the optical fiber, and an axis shift amount measurement member. For driving the piezoelectric adjustment member based on the measured axis deviation. A plurality of optical fibers individually held by a plurality of V-shaped grooves, and the vicinity of the tip of each individually held optical fiber is adjacent to the V-shaped groove. And placed in a single-core holding groove arranged so as to communicate with, while aligning the axis by the piezoelectric fine adjustment member and the drive control member, melting the optical fiber tip by the melting means and the opposing optical fiber tip. Since the connection can be made, it is possible to connect the multi-core optical fiber core wires, which has been difficult in the past, with high accuracy, and the optical fiber can be connected on a two-dimensional plane orthogonal to the central axis of the optical fiber. The fine adjustment allows the axis to be aligned without being affected even if dust or the like is present between the V-shaped groove and the optical fiber. An effect that can be achieved transfected discrete axis alignment mechanism.

[Brief description of the drawings]

FIG. 1 is a front view for explaining a schematic configuration of a multi-core optical fiber connecting device according to the present invention.

FIG. 2 is a side view of the device shown in FIG.

FIG. 3 is a side view of a fine adjustment plate provided in the multi-core optical fiber connection device according to the present invention.

FIG. 4 is a front view of the fine adjustment plate shown in FIG. 3;

FIG. 5 is a side view of a piezoelectric fine adjustment member provided in the multi-core optical fiber cable connecting device according to the present invention.

FIG. 6 is a view for explaining a fine adjustment operation by a piezoelectric fine adjustment member provided in the multi-core optical fiber connecting device according to the present invention.

FIG. 7 is a diagram for explaining a fine adjustment operation by a piezoelectric fine adjustment member provided in the multi-core optical fiber connecting device according to the present invention.

FIG. 8 is a diagram for explaining a fine adjustment operation by a piezoelectric fine adjustment member provided in the multi-core optical fiber connecting device according to the present invention.

FIG. 9 is a view for explaining a fine adjustment operation by a piezoelectric fine adjustment member provided in the multi-core optical fiber connecting device according to the present invention.

FIG. 10 is a diagram for explaining a fine adjustment operation by a piezoelectric fine adjustment member provided in the multi-core optical fiber connecting device according to the present invention.

FIG. 11 is a schematic diagram of an axis alignment control circuit provided in the multi-core optical fiber cable connection device according to the present invention.

FIG. 12 is a diagram for explaining a schematic configuration of a conventional multi-core optical fiber cable connecting device.

FIG. 13 is a diagram illustrating a characteristic curve showing a relationship between an axis shift amount and a connection loss due to the axis shift.

FIG. 14 is a perspective view for explaining a schematic configuration of a conventional single-body alignment device.

FIG. 15 is a perspective view for explaining a schematic configuration of a conventional single-body alignment device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tape core wire 1a optical fiber 10 V-groove substrate 10a V-shaped groove 11 base 13 fine adjustment plate (optical fiber support member) 13a single-core holding groove 13c protrusion 13d inverted triangular member 14 piezoelectric fine adjustment member 15a, 15b trapezoid Shape member 16a, 16b Piezoelectric element 17 Spring 31 Axis misalignment measuring device 32 Controller 33 Amplifier

Continuation of front page (56) References JP-A-63-150603 (JP, A) Aoshima et al. , "Compact Mass Axis Alignment Device with Piezoelements for Optical Fibers", IEEE Photonics Technology Letters, (USP), Survey, April 1992, April 1992. Field (Int.Cl. ⁷ , DB name) G02B 6/00-6/02 G02B 6/10 G02B 6/16-6/26 G02B 6/30-6/44

Claims (1)

(57) [Claims] 1. A multi-core V-groove method based on a multi-core batch V-groove method, comprising a base, and two members having the same configuration and provided on the base and symmetrically arranged around a melting means. In a connection device for performing multi-core collective connection of a plurality of optical fibers constituting a core optical fiber, the member group includes a V-groove formed with a plurality of V-shaped grooves for individually holding the plurality of optical fibers. A plurality of substrates, each of which has a single-core holding groove that is disposed adjacent to and communicates with the V-shaped groove and that supports the vicinity of the distal end of the optical fiber protruding from one end of the V-shaped groove. A fine adjustment plate, swingably supporting the fine adjustment plate, and a plurality of substrate supports fixed on the base, slidably connected to the fine adjustment plate, and By finely moving the fine adjustment plate, the optical fiber is A plurality of piezoelectric fine adjustment members for finely moving on a two-dimensional plane orthogonal to a central axis; a member for slidably connecting the fine adjustment plate and the fine adjustment member; And a drive control member for driving the piezoelectric adjustment member based on the amount of axis deviation measured by the axis deviation amount measurement member. Multi-core optical fiber cable connecting device.