JP5074805B2 - Assembly method of mechanical splice - Google Patents

Description

  The present invention relates to a mechanical splice for abutting and connecting opposing optical fibers.

  Conventionally, as a device for connecting optical fibers, mechanical splices are known that are fixed in a state in which end faces of optical fibers are butted together (see, for example, Patent Documents 1 and 2).

  In the techniques described in Patent Documents 1 and 2, first, the end surfaces of both optical fibers to be connected are removed to treat the end surfaces, inserted into the grooves of the support portions, and the end surfaces of both optical fibers are brought into contact with each other, Both optical fibers are aligned by pressing with a hard member. At this time, the optical fibers are bent so that the contact surfaces are pressed by a repulsive force to extend the optical fibers so that the connection can be made reliably.

JP 59-218415 A JP 2000-56178 A

  By the way, in the mechanical splice described in Patent Document 1, in order to ensure the alignment accuracy of the optical fiber, it is necessary to remove the coating and align and fix the glass fiber based on the outer diameter. Therefore, after removing the coating, it is necessary to clean the exposed glass fiber and cut it into a predetermined length, which increases the number of man-hours for the connection work. Further, since the glass is exposed by peeling off the coating of the optical fiber, the operator's hand or the like may be damaged during the connection work.

  Furthermore, since the coating is removed and the glass is used, the glass portion may be damaged during the connection work. In such a case, the strength of the optical fiber is reduced, and in the worst case, there is a possibility of disconnection.

  In addition, since the mechanical splice is usually made of a resin material such as PPS or epoxy, when the glass fiber is inserted along the V-groove of the mechanical splice substrate at the time of connection, the edge of the glass scrapes the resin. There is a possibility of connecting in a state where dust is involved, and the initial characteristics are difficult to stabilize.

  Also, in the mechanical splice that has been connected, the linear expansion coefficient of the optical fiber is different from the linear expansion coefficient of the resin mechanical splice body. There is a risk of inviting.

  Furthermore, since the connection cannot be confirmed, there is a possibility that the connection work is completed in a state where the end face of the optical fiber is not sufficiently abutted.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanical splice and a mechanical splice assembly method capable of reducing connection man-hours while improving work safety and improving connection reliability.

  The mechanical splice according to the present invention for solving the above-mentioned problems is a connection having a fiber fixing portion for fixing each of the opposed optical fibers on the substrate, and a butting portion for connecting the optical fibers while aligning each other. And a bending portion in which a bending space allowing the bending of the optical fiber is formed between the connection portion and the fiber fixing portion, and the connection portion is the light introduced into the connection portion. The fiber is configured to be housed in a state of being bent toward the abutting portion.

  In the mechanical splice according to the present invention, it is preferable that the connection portion is provided with a pressing portion that bends the optical fiber toward the butting portion.

  In the mechanical splice according to the present invention, it is preferable that the pressing portion has a predetermined clearance with respect to the optical fiber at the abutting portion.

  Further, in the mechanical splice according to the present invention, an insertion taper portion that guides the optical fiber to a bottom portion of the connection portion along the insertion direction is provided at a portion corresponding to both ends of the optical fiber in the longitudinal direction in the pressing portion. It is preferable to be provided.

  Moreover, in the mechanical splice according to the present invention, it is preferable that a step is provided between a bottom portion of the connection portion and a bottom portion of the bending portion, and the butt portion is provided at the bottom portion of the connection portion.

  In the mechanical splice according to the present invention, it is preferable that the abutting portion is formed of a groove having a V-shaped or U-shaped cross section.

  In the mechanical splice according to the present invention, it is preferable that the bending portion is provided only on one side with respect to the connection portion.

  In the mechanical splice according to the present invention, it is preferable that the connection portion is provided with an air escape groove connected to the butt portion.

  In the mechanical splice according to the present invention, it is preferable that a refractive index matching material is provided inside the connecting portion.

  In order to solve the above problems, the mechanical splice assembly method according to the present invention includes a fiber fixing portion for fixing each of the opposed coated optical fibers on a substrate, and alignment with the optical fibers coated. A method of assembling a mechanical splice having a connection portion that is connected while being abutted, and inserting a coated optical fiber from one of the mechanical splices and inserting a coated optical fiber from the other, A step of abutting the optical fibers in a bent state at a connecting portion; a step of bending at least one of the optical fibers between the connecting portion and the fiber fixing portion; and And a step of fixing to the fixing portion.

  According to the present invention, at the connection portion, the optical fibers with the coatings are aligned, bent and connected toward the abutting portion, and at least one light is connected between the connection portion and the fiber fixing portion. The fibers are bent to fix both optical fibers to the fiber fixing part. Therefore, the end of the optical fiber can be stably positioned in the abutting portion by bending the optical fiber toward the abutting portion at the connecting portion. Furthermore, since the optical fiber is bent in the bending space and biased toward the other optical fiber, the connection state between the optical fibers can be maintained with high reliability.

  Hereinafter, an example of an embodiment of a mechanical splice and an assembly method of the mechanical splice according to the present invention will be described in detail based on the drawings.

  1 is a schematic configuration diagram showing an embodiment of a mechanical splice according to the present invention, FIG. 2 is a perspective view of the mechanical splice showing a state in which a clamp spring is removed, FIG. 3 is an exploded perspective view of the mechanical splice, and FIG. Is a cross-sectional view taken along the axis of the connecting portion, FIG. 4B is an enlarged cross-sectional view at the position BB in FIG. 4A, FIG. 5 is a cross-sectional view showing the state of the optical fiber in the connecting portion, and FIG. 7 is a perspective view of the connection lid as viewed from above, FIG. 7 is a perspective view of the connection lid as viewed from below, FIG. 8 is an exploded perspective view showing an assembled state of the connection lid and the fixing lid, and FIG. FIG. 9B is an explanatory diagram showing a moving state of the optical fiber when the bent portion is rectangular.

  As shown in FIGS. 1 and 2, the mechanical splice 10 of the present embodiment has an overall rectangular substrate 20 over its entire length, and the upper surface 20a (the upper surface in FIG. 1) of the substrate 20 A straight V-groove-shaped guide groove 21 is formed along the longitudinal direction, that is, the axial direction of the optical fibers 11 and 12 to be connected (the left-right direction in FIG. 1). Thereby, the optical fibers 11 and 12 can be guided on the same axis in a state of being opposed to each other.

  Corresponding to the left and right ends of the substrate 20, fiber fixing portions 30R and 30L for fixing the optical fibers 11 and 12 to be connected are provided, and the optical fibers 11 and 12 are pressed against the guide grooves 21 of the substrate 20, respectively. Fixing lids 31 </ b> R and 31 </ b> L are provided to face the substrate 20.

  Further, adjacent to the fiber fixing portion 30 </ b> L, a connection portion 40 that connects the optical fibers 11 and 12 while being aligned is provided, and a connection lid 41 that faces the substrate 20 is provided. The connection portion 40 is configured to be housed in a state where the optical fibers 11 and 12 introduced into the connection portion 40 are bent.

  Further, a bent portion 51 is formed between the connecting portion 40 and the right-side fiber fixing portion 30R. The bent portion 51 is formed to allow the optical fiber 11 to bend and generate a pressing force between the optical fibers 11 and 12. 50 is provided. The substrate 20, the fixed lids 31R and 31L, and the connection lid 41 are made of hard plastic such as PPS resin or epoxy resin.

  The upper surfaces of the left and right fixed lids 31R and 31L, the upper surface of the connection lid 41, and the height position (the thickness from the lower surface of the substrate 20) of the upper end surface 20c of the substrate 20 in the bent portion 50 are substantially on the same plane throughout the entire length. A clamp spring 13 having a U-shaped cross-section is provided over almost the entire length of the substrate 20 so that the fixing lids 31R and 31L and the connection lid 41 are sandwiched and joined together with the substrate 20 and the optical fibers 11 and 12 are pressed and fixed. Yes. Note that pressing portions 31b and 41a having horizontal surfaces are provided on the upper surfaces of the fixed lids 31R and 31L and the upper surface of the connection lid 41, respectively, so that the clamp springs 13 can securely hold the pressing portions 31b and 41a. The material of the clamp spring 13 is, for example, beryllium copper.

  As shown in FIG. 3, the above-described guide grooves 21 corresponding to the left and right fiber fixing portions 30 </ b> R and 30 </ b> L and the bending portion 50 are provided in a straight line on the upper surface 20 a of the substrate 20, and correspond to the connection portion 40. A V-groove 42 is provided. Further, in the bent portion 50, both side walls 20b of the substrate 20 have almost the entire height of the mechanical splice 10, and a bent space 51 having a V-shaped cross section with the guide groove 21 as the bottom at the lower end in the central portion. Is formed.

  Note that conical tapered portions 23 having the guide grooves 21 as apexes are formed on both end surfaces of the substrate 20. Also, the same tapered portion 31 a is provided on the end surfaces of the fixed lids 31 </ b> R and 31 </ b> L, and a conical shape is formed together with the tapered portion 23. This facilitates insertion of the optical fibers 11 and 12 into the guide groove 21.

  As shown in FIGS. 3 and 4, the connection portion 40 on the upper surface of the substrate 20 is provided with a rectangular recess 45 having a depth H, and a V groove 42 for alignment is provided at the bottom of the recess 45. ing. The V-groove 42 has a step 42 a (height H) between the guide groove 21 of the left fixed portion 30 </ b> L and the bottom of the bending space 51 of the bending portion 50, and is provided in the bending space 51 and the upper surface 20 a of the substrate 20. It is provided at a position lower than the guide groove 21 that is present. The V groove 42 may be a U groove having a U-shaped cross section.

  On the other hand, as shown in FIGS. 6 and 7, an overall rectangular pressing portion 43 that fits into a recess 45 provided in the connection portion 40 is provided on the lower portion of the connection lid 41 so as to protrude downward. . A slit 46 for guiding the optical fibers 11 and 12 is provided in a concave shape along the axial direction at the center of the holding portion 43, and the optical fibers 11 and 12 are inserted into the V-groove along the insertion direction at both ends of the slit 46. An insertion taper portion 46a (see FIGS. 5 and 7) leading to 42 is provided. In addition, an air escape groove 43 a orthogonal to the insertion direction is provided on the lower surface of the pressing portion 43 from the slit 46 to the outer surface. Thus, an air escape path is formed when the optical fibers 11 and 12 are inserted along the slit 46, and the optical fibers 11 and 12 can be easily inserted without causing a compression resistance of the air.

  As shown in FIG. 5, the optical fibers 11 and 12 are pressed by the lower end 46 b of the insertion taper portion 46 a and a downward bending force acts, and the connection position 44 is a butt portion between the optical fibers 11 and 12. In FIG. 4, since the optical fibers 11 and 12 are urged toward the V-groove 42 (downward in FIG. 5), the optical fibers 11 and 12 and the slit 46 are interposed as shown in FIG. Clearance β is provided. For this reason, the optical fibers 11 and 12 are aligned at the connection position 44 without being pressed.

  In order to reduce the axial displacement and reduce the connection loss, it is desirable to reduce the clearance β. However, since the formation accuracy of the V-groove 42 and the formation accuracy of the connection lid 41 are both resin molded products, several It is difficult to obtain a dimensional accuracy of μm. For this reason, it is good to set the clearance which considered the variation of the dimension of shaping | molding, and to align and connect the optical fibers 11 and 12 with high precision.

  Further, a refractive index matching material 47 is provided at the connection position 44, and the refractive index matching material 47 is included between the end faces when the optical fibers 11 and 12 on both the left and right sides are butted. As the refractive index matching material 47, grease for refractive index matching or a thin film sheet can be used.

  Thus, there is a step between the bottom of the connecting portion 40 (the bottom of the V-groove 42) and the bottom of the bending portion 50 (the bottom of the bending space 51), and the V-groove 42 of the connecting portion 40 Since it is formed lower than the bottom, it is possible to introduce the optical fibers 11 and 12 with the coating on them into the connecting portion 40 along the bottom of the bending space 51. In the connecting portion 40, the end portions of the optical fibers 11 and 12 can be stably positioned in the V-groove 42 by bending the optical fibers 11 and 12 toward the bottom of the V-groove 42 by the pressing portion 43. it can. Thereby, the reduction | decrease of the axial shift loss of the optical fibers 11 and 12 can be aimed at.

  Further, when the optical fibers 11 and 12 are inserted into the V-groove 42 along the insertion taper portion 46a, the air between the V-groove 42 and the holding portion 43 is pushed out of the air escape groove 43a and escapes. When the fibers 11 and 12 are butted together, they can be easily inserted without causing air compression resistance.

  As shown in FIG. 9A, the bending space 51 in the bending portion 50 is V-shaped. Accordingly, when an axial compressive force is applied to the optical fiber 11 inserted along the guide groove 21, the optical fiber 11 has a bending portion 50 as compared to the rectangular shape shown in FIG. 9B. It is possible to smoothly move upward and bend without being caught inside, so that the end faces of both optical fibers 11 and 12 can be pressed and brought into contact with each other with a predetermined pressing force.

The clamp spring 13 shown in FIGS. 2 and 3 has a structure that covers the upper surface of the bent portion 50. However, if the structure is such that the upper surface of the bent portion 50 is not covered as shown in FIG. The state of bending of the optical fiber 11 in the space 51 can be visually confirmed.
Further, in the example of the present embodiment, the optical fibers 11 and 12 are pressed and bent toward the connection position 44 by the pressing portion 43 of the connection portion 40. However, for example, the optical fibers 11 and 12 are provided on both sides of the connection portion 40. A passage for introducing 12 into the connection position 44 (butting portion) may be formed so as to be inclined obliquely downward, and the optical fibers 11 and 12 may be bent toward the connection position 44 through the passage.

Next, a method for assembling the mechanical splice of this embodiment will be described.
FIGS. 10A to 10G are process diagrams showing a mechanical splice assembly method.

  As shown in FIG. 10 (A), the mechanical splice 10 is set on a connecting tool 14 for positioning and connecting the mechanical splice 10, and the wedge member 15 is placed at two locations as shown in FIG. 10 (B). And the substrate 20 and the fixed lids 31R and 31L and the connection lid 41 are opened to release the bonding. Next, as shown in FIG. 10C, the coated optical fibers 11 and 12 held by the holding tool 16 are inserted from the left and right sides of the mechanical splice 10 and also from the other side.

  At that time, the optical fibers 11 and 12 held by the holding tool 16 are cut in advance by a fiber cutter so that the protruding length from the holding tool 16 becomes a predetermined length. Further, when the length from the connection position 44 on the side where the bending portion 50 is provided to the connection portion 40 (here, the right side) to the end surface of the connection tool 14 is L, the optical fiber protruding from the gripping tool 16 The lengths 11 and 12 are longer by a predetermined amount α. Further, the spacer 17 is attached to the side where the bent portion 50 is not provided with respect to the connecting portion 40 (here, the left side) so that the length from the connecting position 44 to the outer surface of the spacer 17 is L.

  Next, as shown in FIG. 10D, the optical fibers 11 and 12 are held until the gripping tool 16 comes into contact with the connection tool 14 or the spacer 17, that is, until the optical fibers 11 and 12 are arranged at the fixed positions. Is inserted into the guide groove 21 of the mechanical splice 10. The optical fibers 11 and 12 are bent downward along the slit 46 of the connection lid 41 at the connection portion 40 and are pressed while being bent toward the bottom of the V-groove 42 by the pressing portion 43. Aligned by.

  At this time, it is preferable to insert the optical fiber 11 on one side first from the side (right side) where the bending portion 50 is provided, and then insert the optical fiber 12 on the other side (left side). As a result, the optical fibers 11 and 12 abut at the connection position 44, and the optical fiber 11 is bent by a predetermined amount in the bending space 51 in order to absorb the extra length α of the optical fibers 11 and 12. The optical fiber 11 is bent at a center portion of the bending space 51 in a direction away from the bottom portion of the bending space 51 (that is, the guide groove 21) (see FIG. 1), and the optical fiber 11 is inserted into the round hole 43 at a portion inserted. The force acts so as to be pressed against the bottom of the bending space 51. And when the upper surface of the bending part 50 is not covered with the clamp spring 13, it is confirmed visually that the optical fiber 11 is certainly bent.

  In a state where the optical fiber 11 is bent, as shown in FIG. 10E, the wedge members 15 and 15 are removed, and the fixing lids 31R and 31L and the substrate 20 are joined by the pressing force of the clamp spring 13, and both The optical fibers 11 and 12 are fixed to the guide groove 21. When the gripping tool 16 is removed (see FIG. 10F), the spacer 17 is further removed, and the mechanical splice 10 is taken out from the connection tool 14 (see FIG. 10G), the connection work is completed.

  According to the mechanical splice 10 and the method for assembling the mechanical splice 10 described above, the guide groove 21 is provided in a straight line corresponding to the fiber fixing portions 30R and 30L and the bending portion 50, and the optical fiber with the coating still attached. 11 and 12 can be introduced into the connecting portion 40 along the bottom of the bending space 51. The connection portion 40 is provided with a V-groove 42 at a position lower than the bottom of the bending space 51 (that is, the guide groove 21), and the holding portions 43 bend the optical fibers 11 and 12 toward the bottom of the V-groove 42. Thus, the end portions of the optical fibers 11 and 12 can be stably positioned in the V-groove 42. As a result, it is possible to improve the connection reliability by reducing the axial misalignment loss of the optical fibers 11 and 12.

  And in the connection part 40, since clearance (beta) is provided between the holding | suppressing part 43 and the optical fibers 11 and 12, and the optical fibers 11 and 12 are not pressed to radial direction, the optical fibers 11 and 12 are provided. No side pressure is applied to the cover, and there is no deformation of the coating. Therefore, the optical fibers 11 and 12 can be aligned with high accuracy at a predetermined position in the V groove 42.

  Further, since the optical fiber 11 is deflected in the bending space 51 and is biased toward the counterpart optical fiber 12, the optical fibers 11 and 12 themselves are not affected by the contraction difference of each part of the mechanical splice 10. The pressing force always acts on the connection surface, and the connection state between the optical fibers 11 and 12 can be maintained with high reliability.

  That is, the coated optical fibers 11 and 12 can be easily connected with a small number of connection steps, and the connection reliability is good. In addition, since the optical fibers 11 and 12 can be connected without being covered, the safety of the connection work can be ensured, and when the optical fibers 11 and 12 are inserted into the mechanical splice 10, the glass of the optical fibers 11 and 12 is removed. It is possible to prevent the resin portion of the mechanical splice 10 from being cut.

In the above-described embodiment, the bent portion 50 obtained by bending the optical fiber 11 is provided only on one side (right side) with respect to the connection portion 40, but may be provided on both the left and right sides of the connection portion 40.
Further, the bending space 51 is not limited to a V-shaped cross section, and may be a U-shaped cross section, for example.
Moreover, although the level | step difference provided between the bottom part of the connection part 40 and the bottom part of the bending part 50 was made into the downward direction in the said embodiment, it may be an upper direction or a horizontal direction. In that case, what is necessary is just to bend the optical fibers 11 and 12 in the direction of the level | step difference in the connection part 40. FIG.

Next, an embodiment of the mechanical splice 10 according to the present invention will be described.
Optical fibers 11 and 12 having a glass diameter of 80 μm and a coating outer diameter of 125 μm are used. Further, an optical fiber resistant to bending is preferable. For example, in the case of a single mode fiber, the core diameter is about 10 μm and the MFD (mode field diameter) is 8 to 9 μm. In the case of a multimode fiber (MMF), the core / clad relative refractive index difference Δn is 1.9%. Further, the coating layer is, for example, a single layer coating with a urethane acrylate ultraviolet curable resin having a Young's modulus of 980 MPa. Since this optical fiber has a thin coating layer (22.5 μm) and a single-layer coating, the outer diameter can be controlled to 1 μm or less.

(Flexible part)
First, in the bending part 50, if the length of the bending space 51 is shortened, the buckling force increases. On the other hand, the radius of curvature of the optical fiber 11 decreases, and the bending loss increases and the possibility of bending breakage increases. . It is necessary to set the bending length and the pushing amount according to the optical fibers 11 and 12 to be applied. Here, a case where a thin multimode fiber with Δn = 1.9% is used will be described.
Fiber push-in amount: 0.4 ± 0.3 mm (0.1 to 0.7 μm) in consideration of variation in cut length.
Deflection loss: 0.05 dB or less in consideration of low loss.
-Curvature radius: 3 mm or more in consideration of breaking strength.

In the measurement, the amount of deflection of the optical fiber was set using two single-core capillaries, and the optical fiber not fixed from one side was pushed in to make a bend, and the transmission loss at that time was measured. Here, an LED light source having a wavelength of 0.85 μm was used. As a result, the bending length satisfying the above conditions was 6 mm or more. Further, from the calculation results of the fiber push-in amount and the fiber curvature radius at each bending length, the bending length satisfying the above condition was about 11 mm or more. From the above results, the bending length is 11 mm or more. However, since the range of the push-in amount can be narrowed by improving the fiber cutting accuracy, the lower limit of the bending length is about 6 mm, and the upper limit is restricted by the length of the mechanical splice. In actual use, it is about 20 mm.
The cross-sectional shape of the bending portion is V-shaped, and the angle is 30 to 120 °. The preferred range is 45-90 °, and in the example 60 °.

(Connection part)
In order to maintain the coupling by the bending force, a clearance β (FIG. 4 (FIG. It is preferable to ensure B). On the other hand, in order to ensure low loss, the connection characteristic (loss) is determined by the clearance, so that a low clearance is desirable as much as possible. Here, the buckling force when the thin fiber is bent is as small as 1/9 compared with a normal optical fiber having a glass diameter of 125 μm, and the buckling force when the set deflection length is 11 mm is about 4 gf. For this reason, if there is a clearance of at least 0.1 mm, the optical fiber can be inserted. Therefore, the hole diameter is preferably 0.1 mm or more larger than the maximum value of the outer diameter of the coating, and the hole diameter tolerance is desirably ± 0.5 mm or less from the viewpoint of connection loss (axial deviation).

  As described above, the V groove 42 is provided with the step 42a (height H) and is provided at a position lower than the bottom of the bending space 51 and the bottom of the guide groove 21 provided on the upper surface 20a of the substrate 20. ing. Generally, as the offset amount of the optical fibers 11 and 12, that is, the height of the step H is larger, the bending force of the optical fibers 11 and 12 increases, and the grounding accuracy to the V groove 42 is improved. On the other hand, when the bending force of the optical fiber is increased, insertability is impaired. Further, in the design of the bending length in the bending portion 50, since the buckling force when the thin fiber is bent is as small as about 4 gf, for example, the fiber can be inserted by this buckling force and low loss (V-groove grounding property) is achieved. It is necessary to set the height H of the step to be compatible and the fiber insertion angle θ.

  As shown in FIG. 5, when the distance from the lower end 46b of the insertion tapered portion 46a to the step 42a of the V groove 42 is L1 and the height of the step is H, the optical fibers 11 and 12 are inserted. The angle θ and the fiber bending force (grounding property≈loss) are determined. Here, the V-groove length L2 of the fiber grounding portion was set to L2 = 2 mm, L1 = 2 mm, and H = 0.1 to 0.5 mm, and the connection loss and the fiber insertion property (possibility of insertion) were evaluated. The optical fibers 11 and 12 were coated with a small diameter MMF, and a refractive index matching material 47 was applied to the connection position 44. Moreover, 0.85 micrometer LED was used as a measurement light source.

  As a result, it was confirmed that the connection loss tends to decrease as the height H of the step 42a increases. Further, when the height H is 500 μm or more, the optical fibers 11 and 12 cannot be inserted. Therefore, when a small-diameter MMF fiber is used, the height H of the step 42a is 200 to 500 μm, preferably 300 to 400 μm (for example, H = 350 μm). In the case of a general optical fiber having a glass diameter of 125 μm, the fiber buckling force is increased, so that the range is larger than that of a thin fiber. Further, the gap between the bottom of the V groove 42 and the bottom of the pressing portion 43 in the connecting portion 40 is the clearance β between the bottom of the pressing portion 43 and the optical fibers 11 and 12 (for example, 5 to 100 μm, preferably 15 ± 10 μm). From 130 to 225 μm.

(Fixed part)
In the conventional mechanical splice, a holding force is mainly generated in the glass fiber portion. However, in the present mechanical splice 10, the coated optical fibers 11 and 12 are held. In this case, the design points are the length and pressing force of the fixed lids 31R and 31L that achieve both a fiber gripping force and low loss. The small-diameter optical fibers 11 and 12 set on the V-groove (guide groove) were pressed by the fixed lids 31R and 31L having respective lengths, and the fiber pulling load and bending loss at that time were measured. The judgment criteria were fiber gripping force> 5N and pressing loss <0.05 dB. In order to satisfy these, the length of the fixed lid was 5 mm or more, and the pressing load was 3 kgf or more. In actual use, the length of the fixed lid is 15 mm or less due to size restrictions, and the upper limit of the load is about 5 kgf due to loss restrictions. From the above, the length of each of the fixing lids 31R and 31L is 8 mm, the length of the fixing portion for fixing the optical fiber is 6 mm, and the length of the insertion taper portion 31a is 2 mm. Further, the depth of the guide groove 21 is set such that the cross-sectional area of the optical fibers 11 and 12 and the cross-sectional area of the guide groove 21 are substantially equal (0.8 to 1.2 times). Therefore, the angle of the guide groove 21 is 60 ° and the depth is about 140 μm.

It is a schematic block diagram which shows embodiment which concerns on the mechanical splice of this invention. It is a perspective view of the mechanical splice which shows the state which removed the clamp spring. It is a disassembled perspective view of a mechanical splice. (A) is sectional drawing along the axis line of a connection part, (B) is an expanded sectional view of the BB position in FIG. 4 (A). It is a cross-sectional schematic diagram which shows the state of the fiber in a connection part. It is the perspective view seen from the upper part which shows the connection cover in a connection part. It is the perspective view seen from the lower part which shows the connection cover in a connection part. It is a disassembled perspective view which shows the assembly | attachment state of a connection lid and a fixed lid. (A) is explanatory drawing which shows the movement state of an optical fiber in case a bending part is V shape, (B) is explanatory drawing which shows the movement state of an optical fiber in case a bending part is rectangular shape. It is process drawing which shows the assembly method of a mechanical splice.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mechanical splice 11, 12 Covered optical fiber 13 Clamp spring 20 Board | substrate 21 Guide groove 30 Fiber fixing part 31R, 31L Fixing lid 40 Connection part 42 V groove 42a Step 43 Pressing part 43a Air escape groove 44 Connection position (butting Part)
46a Insertion taper portion 47 Refractive index matching material 50 Deflection portion 51 Deflection space β Clearance

Claims (4)

A fiber fixing part for fixing each of the optical fibers with coatings facing each other on the substrate;
A connecting portion having a butting portion for connecting and connecting the optical fibers while being aligned in a coated state ;
A bending portion in which a bending space allowing the bending of the optical fiber is formed between the connection portion and the fiber fixing portion, and
The bending portion is provided only on one side with respect to the connection portion, and the bending space is an assembly method of a mechanical splice that is visible from the outside,
After inserting the coated optical fiber from the one side of the mechanical splice, inserting the coated optical fiber from the other side, and abutting the optical fiber in a bent state at the connection portion;
Bending the optical fiber on the one side in the bending space and visually checking the bending;
A method of assembling the mechanical splice, comprising: fixing both of the optical fibers to the fiber fixing portion. The mechanical splice assembly method according to claim 1,
A mechanical splice assembling method, comprising: a step between a bottom portion of the connection portion and a bottom portion of the flexure portion; and the butt portion at the bottom portion of the connection portion. The mechanical splice assembly method according to claim 2,
An assembly method of a mechanical splice, wherein the connection portion is provided with an air escape groove connected to the butting portion. The mechanical splice assembly method according to claim 3 ,
Before inserting the optical fiber into the connection part, a refractive index matching material is provided inside the connection part.

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