JP3718610B2 - Optical connector ferrule, optical connector, and optical connector assembling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technical field of an optical connector used for connecting optical fibers to each other, particularly an MT connector (Mechanical Transferable Connector).
[0002]
[Prior art]
In order to connect the optical fibers, first, the distal ends of one or more pairs of optical fibers to be connected are inserted into an optical fiber insertion hole provided in the optical connector ferrule and fixed with an adhesive. Next, in order to increase the optical coupling efficiency at the time of connection, a mirror surface is formed on the distal end surface of the inserted optical fiber by polishing the distal end portion to obtain an optical fiber connector.
After the pair of optical fiber connectors are formed, the distal ends of the optical fibers are brought into contact with each other to contact the distal end surfaces of the optical fibers to be connected to form an optical coupling, thereby completing the connection.
[0003]
However, in order to connect the optical fibers with low loss, it is necessary to mirror-polish the front end surface with high accuracy. For this purpose, a lot of equipment such as a dedicated polishing machine, a polishing board, and a polishing sheet is required, and polishing work on site is difficult because water and polishing liquid are necessary.
[0004]
As a technique for partially solving this problem, JP-A-1-72105 discloses that an optical fiber piece is inserted and fixed in advance at the tip of a ferrule at a factory in advance, and the tip is polished together with the end face of the optical fiber piece. At the site, an optical fiber cut with an optical fiber cutting machine and having a mirror surface formed on the front end face is inserted into the ferrule from the rear as it is, and is brought into contact with the rear end portion of the optical fiber piece that has already been fixed to the ferrule. A connector assembly method that does not require on-site polishing work is proposed.
[0005]
[Problems to be solved by the invention]
However, in the invention described in Japanese Patent Laid-Open No. 1-72105, the optical fiber must be inserted into the ferrule after cutting the optical fiber to form a mirror surface on the tip surface. If the tip end surface is brought into contact with the entrance of the optical fiber insertion hole of the ferrule or the inner wall surface, a fine flaw occurs, resulting in a new problem that the optical coupling efficiency is lowered and the optical loss is increased.
[0006]
Especially in connection work at the site, the working environment may be inferior, so the end face of the optical fiber formed on the mirror surface by cutting is repeated while the insertion into the ferrule is repeated several times without success. Since this is in contact with the entrance of the optical fiber insertion hole of the ferrule and the inner wall surface, it is inevitable to solve this problem.
[0007]
Therefore, in order to realize an easily assembled ferrule that does not require mirror polishing, an optical fiber can be inserted very easily compared to a conventional ferrule, and the tip surface is a wall surface inside the optical fiber insertion hole. A ferrule that can be inserted without touching is required.
[0008]
In addition, if the inner wall surface of the ferrule optical fiber insertion hole has a convex portion or an edge portion, even if the optical fiber ferrule is successfully inserted, the base portion of the optical fiber is in this part during the period of use after optical connection. Touching or pressing to cause so-called macrobending increases the optical loss, and if contact is made many times, the coating layer is damaged and the scratches expand and eventually the glass layer part breaks. As in the case of ferrules that require mirror polishing, the formation of such convex portions and edge portions must be avoided.
[0009]
In addition, in the case of the MT connector that is the subject of the present invention, since a mechanical impact due to short-time switching such as a high-speed switching machine (CATS) is also applied, as in the case of a ferrule that requires conventional mirror polishing, It must be able to withstand this impact and be used for a long time.
The present invention solves these problems and proposes an optical fiber ferrule that is extremely easy to assemble on-site.
[0010]
[Means for Solving the Problems]
In order to overcome the above problems, the present invention is an optical connector ferrule comprising a ferrule body and an optical connector boot having a tape core wire guide hole for inserting an optical fiber core wire inserted in the rear part thereof, The tape core wire guide hole is composed of a taper-shaped opening and a tape core wire positioning hole, and the taper-shaped opening has a rectangular cross section and is forward from the rear end of the boot (in the present invention, the direction through which the optical fiber is inserted is forward). The opposite direction is referred to as “backward”.) The taper is reduced to a taper shape, and has a cross section aligned with the tape core from the taper end to the front end of the boot, and is JIS K6253 of the optical connector boot material. Is an optical connector ferrule having a hardness of 50 to 100 degrees .
[0011]
This configuration makes it very easy to insert the tip of the optical fiber into the ferrule. As a result, even when the tip of the optical fiber is curled, the optical fiber can be easily inserted into the ferrule without the tip surface of the optical fiber coming into contact with the wall surface of the entrance of the optical fiber insertion hole. This enables an optical connector ferrule that can be easily assembled locally.
In addition, the optical fiber ferrule of the optical connector ferrule of the present invention is positioned in the direction perpendicular to the insertion direction when the optical fiber tape optical fiber is inserted, and each optical fiber at the distal end is positioned in each optical fiber alignment groove. Guiding to the groove prevents the tip surface from coming into contact with the inner wall surface of the ferrule body and causing damage.
[0012]
When the hardness is in the range of 100 degrees or less, even if the tip surface formed on the mirror surface by cutting when the optical fiber ribbon is inserted contacts the inner wall surface of the optical fiber guide hole of the optical connector boot, it is not easily damaged. Is preferred.
[0013]
In addition, if the hardness is in the range of 50 degrees or more, the hardness and strength of the material are essentially different concepts, but there is a substantially close relationship when the material is plastic such as rubber, This is suitable because the strength and shape stability required for an MT connector that requires impact properties can be obtained.
[0014]
In the optical connector ferrule of the present invention, the taper angle θ (see FIGS. 3A and 3B) between the opposing inner wall surfaces of the tapered opening of the connector boot is in the range of 10 to 30 degrees. Insertion of the optical fiber ribbon is particularly easy and preferable.
[0015]
Moreover, the optical connector ferrule of this invention is an optical connector ferrule which has an adhesive filling defect | deletion part in the part inserted in the said ferrule main body on the outer surface of the said optical connector boot.
[0016]
An adhesive filling gap is formed between the adhesive filling defect portion and the inner wall of the boot insertion opening. By filling the gap with an adhesive, it is possible to secure a bonding area that reliably exhibits a predetermined bonding strength, and to reliably obtain the bonding strength required when used as an MT connector.
In addition, the adhesive between the optical connector boot and the ferrule body is peeled off even when mechanical shock due to short-time switching such as a high-speed switching machine (CATS) is repeatedly applied during use after the optical connector is assembled. It can be used for a long time without any problems.
[0017]
Further, the present invention is an optical connector assembled by inserting an optical fiber ribbon having a mirror surface formed on the tip end surface of the optical fiber by cutting into the optical connector ferrule.
[0018]
Further, the present invention is an optical connector assembling method in which an optical fiber ribbon having a mirror surface formed on the front end surface of an optical fiber by cutting is inserted into the optical connector ferrule.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected to the same site | part, and the overlapping description is abbreviate | omitted.
FIG. 1 shows an optical connector assembled by inserting an optical fiber ribbon through the optical connector ferrule of the present invention. 2 and 3 show an optical connector boot which is a main member of the optical connector ferrule. FIG. 4 shows an optical connector assembling method of the present invention.
[0020]
(Configuration of optical connector ferrule)
As illustrated in FIG. 1, the optical connector ferrule of the present invention includes a ferrule body and an optical connector boot.
Reference numeral 20 denotes a ferrule body, and 10 denotes an optical connector boot.
[0021]
(Structure and material of optical connector boot)
The optical connector boot 10 has a tape core wire guide hole 11. The tape core wire guide hole 11 has a tapered opening 11a in which the opening is reduced forward from the rear end 10a of the optical connector boot 10 in a tapered shape, and a front end 10b of the optical connector boot 10 from the tapered end 11b. The optical fiber tape core wire 1 penetrates the optical fiber tape 1 and has a cross-sectional shape matching the optical fiber tape core wire 1.
[0022]
In the tapered opening 11a, since the cross section of the opening expands backward in a tapered shape, it becomes extremely easy to insert the tip of the optical fiber into the ferrule.
In the conventional ferrule, the front end surface of the optical fiber may be damaged by contact with the wall surface of the ferrule entrance of the optical fiber insertion hole. However, when the front end of the optical fiber is curled by the tapered opening 11a, etc. Even if it exists, the damage by such a contact is lost and it becomes possible to insert in a ferrule easily.
[0023]
The optical fiber core positioning hole 11c is positioned in a direction perpendicular to the direction of the optical fiber ribbon 1 when it is inserted, and guides each optical fiber 1a at the tip of the optical fiber alignment groove 23 to each optical fiber alignment groove 23. . Thereby, it can prevent that the front end surface of the optical fiber contacts with the inner wall surface of a ferrule main body, and is damaged.
[0024]
The optical connector boot 10 having the tape core wire guide hole 11 can be inserted into the ferrule body 20 without damaging the mirror surface formed by cutting the tip surface of each optical fiber 1a of the optical fiber tape core wire 1. It becomes easy.
[0025]
On the contrary, when the optical connector boot 10 having the tape core wire guide hole 11 is lacking, the guide function for inserting the optical fiber is lacking, especially when the tip of the optical fiber is curled. Insertion becomes difficult, and the tip surface of the optical fiber is brought into contact with the wall surface of the entrance of the optical fiber insertion hole to increase the probability of damage.
[0026]
Incidentally, since the taper-shaped opening 11a of the tape core wire guide hole 11 is rearwardly enlarged in a taper shape, the angle of the edge portion formed at the entrance is increased, and the usage period of the optical connector after optical connection is increased. Even if the base portion of the optical fiber inserted therein comes into contact with the edge portion, it is difficult to be damaged. That is, even if the contact with this part is repeated, the coating layer is not cut or damaged to the glass part.
[0027]
In addition, since the cross-sectional shape of the tape core wire positioning hole 11c matches the cross-sectional shape of the optical fiber ribbon 1 and almost no gap is generated when the optical fiber ribbon 1 is inserted, The adhesive used when fixing the fiber to the ferrule does not enter the tapered opening 11a.
[0028]
If this adhesive penetrates into the tapered opening 11a, an acute edge portion is formed at the boundary between the surface of the rear end of the cured adhesive resin layer and the optical fiber ribbon 1 inside the tapered opening 11a. When the optical connector is used, macrobending occurs due to contact with this part and optical loss increases, or the coating layer or glass layer of the optical fiber 1 may be damaged due to multiple contact. As expected, this possibility can be eliminated by avoiding the intrusion of the adhesive by the tape core wire positioning hole 11c.
[0029]
Incidentally, a protrusion is formed on the inner wall surface of the taper end 11b. Since the angle of this protrusion is a large obtuse angle, the optical fiber tape core 1 inserted into the tape core guide hole 11 is connected to the optical connector. Repeated contact with this protrusion during use will not cause macrobending or damage.
[0030]
Further, the outer surface of the optical connector boot 10 has a wall surface than the outer surface in the vicinity, which is composed of the chamfered portion 13a and the cutout portion 13b as illustrated in FIGS. 2, 3B, and 3C. An adhesive filling defect 13 formed by scraping is formed.
[0031]
This adhesive filling defect portion 13 is formed with an adhesive filling gap between the optical connector boot 10 and the inner wall of the boot insertion opening 25 in a state where the optical connector boot 10 is inserted into the boot insertion opening 25 of the ferrule body 20. By filling this gap with an adhesive and applying it thicker than the other surface portions, this portion and the inner wall of the boot insertion port 25 can be securely bonded, and the adhesive strength required for use as an MT connector can be obtained. The purpose is to secure.
[0032]
Of course, the adhesive strength can be further increased by applying an adhesive to the portion of the other external surface of the optical connector boot 10 that contacts the inner wall of the boot insertion opening 25.
The place where the adhesive filling defect portion 13 is formed is not particularly limited as long as it is a portion in contact with the inner wall of the boot insertion opening 25 on the outer surface of the optical connector boot 10, but accelerates hardening of the filled adhesive. From the viewpoint, it is preferable that ultraviolet rays, heat rays, and the like are at positions where they can be easily reached from the outside.
Incidentally, the chamfered portion 13a of the adhesive filling defect portion 13 also has a guide function for easily inserting the optical connector boot 10 into the boot insertion opening 25 of the ferrule body 20 due to its surface shape.
[0033]
The surface shape of the adhesive filling defect portion 13 is not limited to the chamfered portion 13a and the cutout portion 13b of the embodiment of the present invention, and various shapes such as a circle and a polygon are possible.
[0034]
If the taper angle θ of the tapered opening 11a of the optical connector boot 10 is too large, especially when the tip of the optical fiber is curled, the tip of the optical fiber comes into contact with the inner wall surface during insertion, and the optical fiber. Will be bent and cannot be inserted. From this viewpoint, the taper angle θ is preferably 30 degrees or less.
However, if the taper angle θ of the tapered opening 11a is too small, the function as an adapter of the optical fiber ribbon 1 is reduced, making it difficult to insert, and the tip of the optical fiber is brought into contact with the wall surface of the boot rear end 10a. 10 degrees or more is preferable because there is a risk of damaging the tip surface.
[0035]
The material of the optical connector boot 10 is preferably rubber such as neoprene or polyphenylene sulfide. The hardness is as small as possible from the viewpoint of not damaging the tip surface of the optical fiber when it comes into contact, and so-called macro bending due to contact with the edge of the boot rear end 10a. Therefore, it is necessary that the hardness of JIS K6253 is 100 or less.
[0036]
On the other hand, if the hardness is too low, the size and shape of the optical connector boot 10 will not be stable, so the hardness according to JIS K6253 must be 50 or more. Incidentally, although the hardness of the material and the lubricity of the wall surface are different concepts, there is a close relationship in the case of rubber or the like. The higher the hardness of the material, the higher the lubricity of the wall surface. From the viewpoint of making the inner wall surface slippery and easy to insert, it is preferable that the hardness according to JIS K6253 is 50 or more.
[0037]
(Ferrule body structure)
As shown in FIGS. 1A and 1C, the ferrule body 20 has an optical connection with an outer diameter of 126 μm to 127 μm with the front end surface of the optical fiber 1a having a diameter of 125 μm exposed at the front end surface. The mouths 21 are formed in a horizontal row.
On both sides of the optical connection ports 21 in a horizontal row on the front end face of the ferrule body 20, guide pin insertion ports 27 are formed for inserting and positioning guide pins of the counterpart optical connector to be connected.
[0038]
An optical fiber positioning hole 22 having the same central axis is formed from the optical connection port 21 toward the rear, as illustrated in FIG. 1A.
The optical fiber positioning hole 22 has a function of positioning and centering the tip portion of each optical fiber 1a of the optical fiber ribbon 1.
[0039]
The optical fiber positioning hole 22 has an optical fiber alignment hole 23a having a common central axis and an outer diameter of about 250 μm, and an upper wall surface having the same outer diameter as the optical fiber alignment hole 23a. The optical fiber alignment groove 23 is continuous.
The optical fiber alignment holes 23a and the optical fiber alignment grooves 23 have a function of guiding the optical fibers 1a at the front end portions to the optical fiber positioning holes 22 and the optical connection ports 21 by aligning them at equal intervals in the lateral direction.
[0040]
A boot insertion opening 25 for inserting the optical connector boot 10 is opened at the rear of the ferrule body 20.
Injecting a rectangular adhesive into the middle region between the region where the optical fiber alignment hole 23a in the front part of the ferrule body 20 is formed and the region where the boot insertion port 25 is formed in the rear part A window 24 is formed, and the optical fiber alignment groove 23 and an adhesive reservoir 26 for accommodating the injected excess adhesive are formed in the lower portion thereof.
[0041]
(Assembly method of optical connector)
First, as illustrated in FIG. 4A, the optical connector boot 10 is temporarily inserted into the boot insertion opening 25 of the ferrule body 20 already manufactured in the factory, and supplied to the site without being bonded. At the site, a cyanoacrylate adhesive is injected from the outside into the gap formed between the adhesive filling defect portion 13 of the optical connector boot 10 and the inner wall surface of the boot insertion opening 25, and is filled and cured. Glue and fix.
[0042]
By removing the collective coating layer at the tip of the optical fiber ribbon 1 and the coating layer of each optical fiber in a lump, the bare optical fibers 1a protrude from the tip separated from each other; To do.
As illustrated in FIG. 4B, the tip portion of each optical fiber 1a is simultaneously cut by an optical fiber cutting machine 30 to form a mirror surface on the tip surface, and has a predetermined length corresponding to the optical connector ferrule. Align.
[0043]
As illustrated in FIG. 4C and FIG. 4D, the optical fiber tape core wire 1 subjected to the terminal treatment is inserted from the tapered opening 11a of the optical connector boot 10 to a position reaching the optical connection port 21. To do. In this case, the optical fiber tape core wire 1 is guided by the tape core wire positioning hole 11c, and each optical fiber 1a at the tip is guided by the optical fiber alignment groove 23, the optical fiber alignment hole 23a, and the optical fiber positioning hole 22, respectively. It can be smoothly and easily inserted into the optical connector ferrule.
[0044]
The length of each fiber 1a at the distal end portion of the optical fiber ribbon 1 is caused by the irregularity of about 20 μm which occurs when the optical fiber 1a is cut, and the irregularity of the distal end position is caused by this irregularity. Cause.
In order to avoid this, a positioning member for assembling an optical connector (not shown) is brought into contact with the distal end surface of each fiber 1a of the optical connection port 21 and pressed rearward so that the distal end position error is within 10 μm. Align the tip position to fit.
[0045]
As illustrated in FIG. 4E, in this state, an instantaneous adhesive, for example, a cyanoacrylate quick-hardening adhesive is poured from the adhesive injection window 24 and cured, thereby positioning the distal end surface of each fiber 1a. Fix and complete the assembly of the optical connector.
[0046]
【The invention's effect】
The optical connector ferrule of the present invention has a rear part of the optical connector ferrule in order to prevent damage caused by contacting the mirror surface at the tip of the optical fiber with the inlet of the insertion hole or the inner wall surface when the optical fiber is inserted into the ferrule. In addition, an optical connector boot made of a material having an appropriate hardness and having a tape core wire guide hole whose opening is enlarged in a taper direction rearward is inserted.
[0047]
By adopting this configuration, the front end surface of the optical fiber is formed into a mirror surface by cutting, while the mirror polishing process of the front end surface of the optical fiber is avoided, and an optical connector ferrule that can be easily assembled on site can be realized. Connection and wiring work of the optical fiber ribbon becomes easy.
[Brief description of the drawings]
FIG. 1 is a diagram showing a state in which an optical fiber ribbon is inserted into an optical connector ferrule of the present invention and assembled to form an optical connector. 1A is a longitudinal sectional view, FIG. 1B is a plan view, and FIG. 1C is a front view.
FIG. 2 is a perspective view showing an optical connector boot of the optical connector ferrule of the present invention.
FIG. 3 is a four-side view showing an optical connector boot of the optical connector ferrule of the present invention. 3A is a longitudinal sectional view, FIG. 3B is a plan view, FIG. 3C is a front end view, and FIG. 3D is a rear end view.
FIG. 4 is a diagram showing an assembly process of the optical connector of the present invention. 4A shows the process of inserting the optical connector boot into the ferrule body, FIG. 4B shows the process of cutting the optical fiber and forming the tip surface into a mirror surface, and FIG. 4C shows the optical connector ferrule. FIG. 4D shows a state where the optical fiber is inserted into the optical connector ferrule, and FIG. 5E shows a state where the optical fiber is bonded and fixed to the optical connector ferrule.
[Explanation of symbols]
1: Optical fiber ribbon 1a: Optical fiber 10: Optical connector boot 10a: Boot rear end 10b: Boot front end 11: Tape core guide hole 11a: Tapered opening 11b: Tapered end 11c: Tape core positioning hole 13: Adhesive filling defect portion 13a: chamfered portion 13b: notch portion 20: ferrule body 21: optical connection port 22: optical fiber positioning hole 23a: optical fiber alignment hole 23: optical fiber alignment groove 24: adhesive injection window 25: boot Insertion slot 26: Adhesive reservoir 27: Guide pin insertion slot

Claims (4)

An optical connector ferrule comprising a ferrule body and an optical connector boot having a tape core wire guide hole for inserting an optical fiber core wire inserted in the rear portion thereof, wherein the tape core wire guide hole has a tapered opening and a tape Comprising a cored wire positioning hole, wherein the tapered opening has a rectangular cross section and is tapered forward from the rear end of the boot, and has a cross section aligned with the tape core wire from the end of the taper. It penetrates to the front end of the boot, the hardness based on JIS K6253 of the material of the optical connector boot is 50 degrees to 100 degrees, and a chamfered portion and a cut portion are cut into a portion to be inserted into the rear portion of the ferrule body on the outer surface of the connector boot. An optical connector ferrule having an adhesive-filled defect portion comprising a notch portion.   2. The optical connector ferrule according to claim 1, wherein a taper angle of the tapered opening is 10 degrees to 30 degrees.   An optical connector, wherein the optical connector ferrule according to 1 or 2 is assembled by inserting an optical fiber tape core wire having a mirror surface formed on the tip end surface of the optical fiber by cutting.   3. An optical connector assembling method, wherein an optical fiber ribbon having a mirror surface formed on a tip surface of an optical fiber by cutting is inserted into the optical connector ferrule according to claim 1.

Images