JP2007298784A - Optical fiber connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain an excellent optical characteristic and to make product quality free from variance, in an optical fiber connector using a refractive index matching film. <P>SOLUTION: An optical fiber connector comprises: a housing part which is equipped with a V groove housing 30 having a refractive index matching film 40, adaptors 51, 52 and protective covers 53, 54; and fiber holders 61, 62 which hold a pair of optical fibers 10, 20 and which are attachably/detachably fitted to the adaptors 51, 52. The V groove housing 30 comprises a V groove housing body 31 and a housing holder 32 provided with a sheet-like elastic pad 33. The optical fibers 10, 20 are abutted on the left and the right faces of the refractive index matching film 40 at each tip end of the fiber core wires, by a pressing force which is equal to or greater than 20 gf×cm through pressure imparting springs 613, 623 of the fiber holders 61, 62 and which is less than the maximum durability thrust of the refractive index matching film 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention is an optical fiber connector comprising a housing having a pair of adapter parts and a pair of fiber holders that hold the pair of optical fibers and are detachably fitted to the adapter parts. The present invention relates to an optical fiber connector in which the ends of unpolished fiber strands of the pair of optical fibers are brought into contact with the left and right surfaces of a refractive index matching film, respectively.

Optical fiber connection devices that connect optical fibers with a refractive index matching agent used by applying a matching oil such as silicon grease or silicon oil must maintain the connector end face normal before application. There is a problem in that the refractive index matching agent is dropped when the attachment and detachment is repeated. Therefore, in order to solve the above-mentioned problems, a number of optical fiber connectors that connect optical fibers with a refractive index matching film interposed therebetween have been proposed.

As disclosed in Japanese Patent No. 2676705 (Patent Document 1), the first conventional optical fiber connector has a refractive index of the core of the optical fiber on the connection end face of the optical fiber connector where the end of the optical fiber is exposed. An optical fiber connector in which a transparent refractive index matching film having a refractive index close to the refractive index and having a thickness of 10 μm or less is directly attached to the end face of the optical fiber without using an adhesive layer or an adhesive layer It is.

As disclosed in Japanese Patent Application Laid-Open No. 2002-31745 (Patent Document 2), the second conventional optical fiber connector fixes the optical fiber core wire to the ferrule, and the end surface of the optical fiber core wire from the ferrule end surface. In the exposed optical connector plug, an optical connector plug characterized in that a resin layer having a refractive index close to the refractive index of the optical fiber core, that is, a refractive index matching resin layer is provided on the end face of the ferrule. is there.

Both the first and second conventional optical fiber connectors described above are configured to connect two optical fibers by fitting optical connectors and ferrules to each other. In order to align the axis of the fiber, high-precision processing is required, and since a pair of components are coupled, there is a problem that the manufacturing cost is high. Further, in the first conventional optical fiber connector, the pressing force of the fiber of the optical fiber to the refractive index matching film, and in the second conventional optical fiber connector, the fiber of the optical fiber to the refractive index matching resin layer. There is a problem that the pressing force of the line is not uniform and there is a variation in optical characteristics, that is, there is a variation in the amount of reflection loss between two connected optical fibers.
Japanese Patent No. 2676705 JP 2002-31745 A

A first problem to be solved by the present invention is to maintain good optical characteristics and to prevent variations in product quality in an optical fiber connector using a refractive index matching film.
The second problem to be solved by the present invention is to provide a high-performance, high-quality, low-cost optical fiber connector in an optical fiber connector using a refractive index matching film.
The third problem to be solved by the present invention is to provide an optical fiber connector that can be used repeatedly in an optical fiber connector using a refractive index matching film.

  In order to solve the above-mentioned problems, research was conducted focusing on the pressing force of the fiber strands of a pair of optical fibers brought into contact with both surfaces of the refractive index matching film. As a result, the present inventors can obtain a good optical characteristic by applying a certain pressing force to the left and right surfaces of the refractive index matching film between the fiber strands of the pair of optical fibers to be connected. It has been found that the pressing force of 20 gf · cm or more should be selected to be a value less than the maximum durable pressing force of the refractive index matching film.

That is, an optical fiber connector that solves the first to third problems described above includes a V-groove housing portion in which a refractive index matching film is accommodated, a connector housing having a pair of adapter portions, and a pair of optical fibers. In an optical fiber connector comprising a pair of fiber holders that are detachably fitted to the adapter part and abut the front ends of the fiber strands of the optical fiber against the left and right surfaces of the refractive index matching film,
A sheet-like elastic pad is provided in the V-groove housing part, and
The fiber holder is provided with a pressing force applying spring, and the leading end of the optical fiber is applied to the refractive index matching film by 20 gf · cm or more and less than the maximum durable pressing force of the refractive index matching film. It was made to contact with the pressing force selected in the range.

According to the present invention, an optical fiber connector using a refractive index matching film, which has a high performance, high quality, and low price while maintaining good optical characteristics and having no variation in product quality, is provided.
The present invention also provides an optical fiber connector using a refractive index matching film, which can be used repeatedly.

An optical fiber connector according to the present invention includes a connector housing having a V-groove housing portion in which a refractive index matching film is accommodated and a pair of adapter portions, and a pair of optical fibers that are detachably fitted to the adapter portions. It is an optical fiber connector comprising a pair of fiber holders in which the tip ends of the fiber strands of the optical fiber are brought into contact with the left and right surfaces of the refractive index matching film with a predetermined pressing force. The fiber holder is provided with a pressing force applying spring for bringing the tip of the optical fiber strand into contact with the refractive index matching film with a predetermined pressing force. The pressing force is 20 gf · cm or more and less than the maximum durable pressing force of the refractive index matching film, for example, 30 gf · cm. The V-groove housing portion is provided with a sheet-like elastic pad for softly storing the optical fiber in the V-groove.

The optical fiber connector according to the first embodiment of the present invention includes a V-groove housing main body 31 having an index matching film 40, an adapter, as shown in the cross-sectional view of FIG. 1, the cross-sectional view of FIG. 2, and the exploded view of FIG. V groove housing part 30 provided with parts 51 and 52 and protective cover parts 53 and 54, and fiber holders 61 and 62 which hold a pair of optical fibers 10 and 20 and are detachably fitted into adapter parts 51 and 52 An optical fiber connector. The refractive index matching film 40 is a 1.5 mm × 1.5 mm rectangular transparent epoxy resin sheet having a thickness of 30 μm and substantially the same refractive index as the optical fibers 10 and 20.

In the optical fibers 10 and 20, the ends of the respective fiber strands are pressed by the pressing force applying springs 613 and 623 of the fiber holders 61 and 62 at 20 gf · cm or more and less than the maximum durable pressing force of the refractive index matching film 40. A pressure is applied to the left and right surfaces of the refractive index matching film 40. The optical fibers 10 and 20 are protected from external impact because the covering portions 12 and 22 are firmly held by the end portions 53a and 54a of the protective cover portions 53 and 54, respectively. Hereinafter, the configuration of the first embodiment will be described in detail.

As shown in FIGS. 2 and 3, the V-groove housing main body 31 of the V-groove housing portion 30 has a wire V-groove 31 b for housing the fiber strand 11 of the left optical fiber 10 and a coating for housing the covering portion 12. The V-groove 31d for the portion, the V-groove 31c for the strand for housing the fiber strand 21 of the right optical fiber 20, the V-groove 31e for the covering portion for housing the covering portion 22, and the storage slit for storing the refractive index matching film 40 31a is formed in the upper surface which is a V-groove formation surface. The storage slit 31a for storing the refractive index matching film 40 is formed at a position sandwiched between the end portions on the center side of the V-groove 31b for strands and the V-groove 31c for strands. Has been.

The V-groove housing retainer 32 is a flat part on both the upper and lower surfaces. The upper surface of the sheet-like elastic pad 33 is bonded to the lower surface of the V-groove housing retainer 32. The sheet-like elastic pad 33 includes a V-groove 33b for housing the fiber 11 of the left optical fiber 10, a V-groove 33d for covering the covering 12, and the fiber 21 of the right optical fiber 20. The housing V groove 33c for housing the covering wire 22 and the housing slit 33a for housing the refractive index matching film 40 are formed on the lower surface which is the V groove forming surface.

The storage slit 33a for storing the refractive index matching film 40 is located at the center side end of the V-groove 33b for strands and the V-groove 33c for strands, and accordingly, the sheet-like elastic pad 33 of the V-groove housing retainer 32. It is formed in the middle on the axis. The sheet-like elastic pad 33 is made of an elastic member such as urethane foam, fluororesin such as Teflon (registered trademark), or polyacetal. The sheet-like elastic pad 33 is a member for softly storing the optical fiber in the V-groove.

The V-groove housing main body 31 and the V-groove housing presser 32 are plastic block members formed by plastic molding, but may be formed of liquid crystal polymer, polyphenylene sulfide, or aluminum.

The left adapter part 51 and the left protective cover part 53 are integrally formed on the left side in the axial direction of the V-groove housing part 30. Similarly, the right adapter portion 52 and the right protective cover portion 54 are integrally formed on the right side of the V-groove housing portion 30 in the axial direction. The left adapter portion 51 into which the left fiber holder 61 is fitted is provided with a cantilever-shaped inner locking claw 51a and a cantilever-shaped outer locking claw 51b. Similarly, the left adapter portion 52 into which the right fiber holder 62 is fitted includes a cantilever-shaped inner locking claw 52a and a cantilever-shaped outer locking claw 52b.

The left fiber holder 61 that holds the left optical fiber 10 includes a small diameter disk 611, a large diameter disk 612, and a pressing force applying spring 613. A holding cylindrical portion 611 a is integrally formed with the small diameter disk 611. A holding hole substantially equal to the diameter of the covering portion 12 of the optical fiber 10 is formed in the holding cylindrical portion 611a. On the other hand, the large-diameter disk 612 has a through-hole having a size that allows the coating portion 12 of the optical fiber 10 to freely pass therethrough. The small-diameter disk 611 and the large-diameter disk 612 are coupled by a coil-shaped pressing force applying spring 613.

Similarly, the right fiber holder 62 that holds the right optical fiber 20 includes a small diameter disk 621, a large diameter disk 622, and a pressing force applying spring 623. A holding cylindrical portion 621 a is integrally formed with the small diameter disk 621. A holding hole substantially equal to the diameter of the covering portion 22 of the optical fiber 20 is formed in the holding cylindrical portion 621a. On the other hand, the large-diameter disk 622 is provided with a through-hole having a size that allows the coating portion 22 of the optical fiber 20 to freely pass therethrough. The small-diameter disk 621 and the large-diameter disk 622 are coupled by a coil-shaped pressing force applying spring 623. When the right fiber holder 62 is fitted into the right adapter portion 52, the small-diameter disk 621 and the large-diameter disk 622 engage with the cantilever-shaped inner locking claw 52a and the cantilever-shaped outer locking claw 52b, respectively. For this reason, the right fiber holder 62 is firmly held by the right adapter portion 52.

A left-side protective cover portion 53 integrally formed on the left side in the axial direction of the V-groove housing portion 30 is a protective cover main body 53b, an openable / closable split type optical fiber holding plate 53a fixed to an end portion thereof, and the illustrated figure. Consists of a protective cover lid that does not. Similarly, a right protective cover portion 54 integrally formed on the right side in the axial direction of the V-groove housing portion 30 includes a protective cover main body 54b, and an openable / closable split optical fiber holding plate 54a fixed to an end portion thereof. And a protective cover lid (not shown).

As shown in the side view of FIG. 4, the left split optical fiber holding plate 53a includes a lower holding plate 531 having a holding recess 531a and a hinge portion, and an upper holding plate 532 having a holding recess 532a and a hinge portion 532b. Has been. The right split optical fiber holding plate 54a has the same structure as the left split optical fiber holding plate 53a.

To assemble the optical fiber connector, the refractive index matching film 40 is attached to the V-groove housing main body 31 and the lid is covered with the V-groove housing presser 32 to which the sheet-like elastic pad 33 is bonded. The refractive index matching film 40 is attached only by inserting the refractive index matching film 40 into the slit housing slit 31 a of the V-groove housing main body 31. The V-groove housing retainer 32 is bonded and fixed to the V-groove housing main body 31. The V groove housing retainer 32 may be detachably attached to the V groove housing main body 31. As described above, since the assembly of the optical fiber connector is simple, the manufacturing cost can be reduced.

The optical fiber 10 is attached to the left fiber holder 61 by inserting the coating portion 12 of the optical fiber 10 into the left fiber holder 61 and adjusting the holding position so that the small diameter disk 611 holds it firmly. The adjustment of the holding position takes into consideration the position where the tip of the fiber strand 11 of the optical fiber 10 abuts the left side surface of the refractive index matching film 40 when the left fiber holder 61 is fitted into the left adapter portion 51. Done.

When the left fiber holder 61 is fitted into the left adapter portion 51, first, it engages with the small-diameter disk 611 of the left fiber holder 61 and the cantilever-shaped inner locking claw 51 a of the left adapter portion 51. The optical fiber 10 firmly held by the small-diameter disk 611 of the left fiber holder 61 is accommodated in the V-groove for strand and the V-groove for covering portion of the V-groove housing 30, and the tip of the fiber strand 11 is refracted. It contacts the left side surface of the rate matching film 40.

The V-groove for wire and the V-groove for covering portion are formed by forming the V-groove 31b for wire and the V-groove 31d for covering portion of the V-groove housing body 31 and the sheet-like elastic pad 33 of the V-groove housing presser 32. It is formed by a wire V groove 31b and a covering portion V groove 33d. For this reason, the holding of the optical fiber 10 by the V-groove for strands and the V-groove for covering portion is not strong, and the pressing force applying spring 613 described later reduces the pressing force applied to the optical fiber 10. No holding force is applied to the optical fiber 10. This is an effect provided with the sheet-like elastic pad 33 of the V-groove housing presser 32.

Next, when the large-diameter disk 612 of the left fiber holder 61 is pushed into the right side of the cantilever-shaped outer locking claw 51b of the left adapter portion 51, the large-diameter disk 612 engages with the cantilever-shaped outer locking claw 51b. Then, the pressing force application spring 613 whose leftward movement is restricted by the large-diameter disk 612 applies a pressing force that pushes the optical fiber 10 to the right via the small-diameter disk 611. As a result, the tip of the fiber strand 11 of the left optical fiber 10 comes into contact with the left side surface of the refractive index matching film 40 with a predetermined pressing force. The predetermined pressing force is 20 gf · cm or more and less than the maximum durable pressing force of the refractive index matching film, for example, 30 gf · cm.

Next, attachment of the optical fiber 20 to the right fiber holder 62 and fitting of the right fiber holder 62 into the right adapter unit 52 will be described.

In other words, the optical fiber 20 is attached to the right fiber holder 62, the covering portion 22 of the optical fiber 20 is inserted into the left fiber holder 62, and the holding position is adjusted to be held by the small diameter disk 621. The adjustment of the holding position takes into account the position where the tip of the fiber strand 21 of the optical fiber 20 abuts the right side surface of the refractive index matching film 40 when the right fiber holder 62 is fitted into the right adapter portion 52. Done.

When the right fiber holder 62 is fitted into the right adapter portion 52, first, the small diameter disc 621 of the right fiber holder 62 and the cantilever-like inner locking claw 52a of the right adapter portion 52 are engaged. The optical fiber 20 firmly held by the small-diameter disk 621 of the right fiber holder 62 is accommodated in the V-groove for strand and the V-groove for covering portion of the V-groove housing 30, and the tip of the fiber strand 21 is refracted. It contacts the right side surface of the rate matching film 40.

The V-groove for wire and the V-groove for covering portion are formed by forming the V-groove 31c for covering wire and the V-groove 31e for covering portion of the V-groove housing main body 31 and the sheet-like elastic pad 33 of the V-groove housing presser 32. It is formed by the wire V-groove 33c and the covering portion V-groove 33e. For this reason, the holding of the optical fiber 20 by the V-groove for the strands and the V-groove for the covering portion is not strong, and the pressing force applied to the optical fiber 20 by the pressing force applying spring 623 described later is reduced. A holding force is not applied to the optical fiber 21. This is an effect provided with the sheet-like elastic pad 33 of the V-groove housing presser 32.

Subsequently, when the large-diameter disk 622 of the right fiber holder 62 is pushed into the left side of the cantilever-shaped outer locking claw 52b of the right adapter portion 52, the large-diameter disk 622 is engaged with the cantilever-shaped outer locking claw 52b. Then, the pressing force application spring 623 whose movement to the right side is restricted by the large diameter disk 622 applies a pressing force to push the optical fiber 20 to the left via the small diameter disk 621. Thus, the tip of the fiber strand 21 of the right optical fiber 20 comes into contact with the right side surface of the refractive index matching film 40 with a predetermined pressing force. The predetermined pressing force is specifically a value of 20 gf · cm or more and less than the maximum durable pressing force of the refractive index matching film.

FIG. 5 is a transmission characteristic diagram showing the relationship between the pressing force of the optical fiber to the refractive index matching film and the return loss. As is apparent from FIG. 8, when the pressing force to the refractive index matching film of the optical fiber is between 10 gf · cm and 20 gf · cm, the return loss varies depending on the sample, but between 20 gf · cm and 50 gf · cm, The reflection attenuation rate of all the samples changes around 50 dB. On the other hand, the maximum durable pressing force of the refractive index matching film 40 which is the soft contact film used in Example 1 was 33 gf · cm at the maximum. Therefore, in Example 1, the range of the predetermined pressing force to the refractive index matching film 40 of the optical fiber was 20 gf · cm at the lower limit and 33 gf · cm at the upper limit. In Example 1, the predetermined pressing force was 30 gf · cm. FIG. 5 shows experimental values of six samples, but the same results were obtained in other experiments.

After the left fiber holder 61 is fitted into the left adapter portion 51, the left optical fiber 10 holds the covering portion 12 on the end portion 53 a of the protective cover portion 53. That is, the left optical fiber 10 is placed on the holding recess 531 a of the lower holding plate 531 by bending the coating portion 12 between the left fiber holder 61 and the end 53 a of the protective cover portion 53, and holding the upper side. The plate 532 is closed. Then, the covering portion 12 of the left optical fiber 10 is sandwiched between the holding recess 531a of the lower holding plate 531 and the holding recess 532a of the upper holding plate 532 and securely held as shown in FIG. . Then, a protective cover lid (not shown) is attached to the protective cover main body 53b, and the left protective cover 53 functions as a cylindrical cover having a rectangular cross section. The left side optical fiber 10 is protected from external impact by the left side protective cover 53, and the tip of the fiber strand 11 of the left side optical fiber 10 can be kept in contact with the left side surface of the refractive index matching film 40 with a predetermined pressing force. .

Similarly, after the right fiber holder 62 is fitted into the right adapter portion 52, the right optical fiber 20 holds the covering portion 22 on the end portion 54 a of the protective cover portion 54. That is, the right optical fiber 20 is placed in the holding recess of the lower holding plate by bending the covering portion 22 between the right fiber holder 62 and the end 54a of the protective cover portion 54, and the upper holding plate. close. Then, the covering portion 22 of the right optical fiber 20 is sandwiched between the holding recess of the lower holding plate and the holding recess of the upper holding plate and securely held. A protective cover lid (not shown) is attached to the protective cover main body 54b, and the left protective cover 54 functions as a cylindrical cover having a rectangular cross section. The right optical fiber 20 is protected from external impact by the right protective cover 54, and the tip of the fiber strand 21 of the right optical fiber 20 can be kept in contact with the right surface of the refractive index matching film 40 with a predetermined pressing force. .

It is sectional drawing which cut | disconnected the typical optical fiber connector of Example 1 of this invention horizontally to the axial direction. It is sectional drawing which cut | disconnected the V-groove housing part of the typical optical fiber connector of Example 1 of this invention perpendicularly | vertically to the axial direction. It is an exploded view of the principal part of the optical fiber connector of Example 1 of this invention. It is the side view of the edge part of the protective cover part of the optical fiber connector of Example 1 of this invention, (A) showed the state which hold | maintained the optical fiber, (B) showed the state which open | released the optical fiber Is. It is the transmission characteristic figure which showed the relationship between the pressing force to the refractive index matching film of an optical fiber, and a return loss.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20 Optical fiber 11, 21 Fiber strand 12, 22 Cover part 30 V groove housing part 31 V groove housing main body 31a Film slit 31b, 31c Wire V groove 31d, 31e Cover V groove 32 V groove Housing retainer 33 Sheet-like elastic pad 33a Film slits 33b and 33c Wire V-grooves 33d and 33e Cover V-groove 40 Refractive index matching film 51 Left adapter 51a Inner locking claw 51b Outer locking claw 51c Stopper 52 Right Adapter 52a Inner locking claw 52b Outer locking claw 52c Stopper 53 Left protective cover 53a End 53b Protective cover body 531 Lower holding plate 531a Holding recess 531c Locking portion 532 Upper holding plate 532a Holding recess 532b Hinge portion 532c Locking Part 54 right protective cover 54a end 54b protective cover Body 61 left fiber holder 611 small diameter disk 611a holding the cylindrical portion 612 a large diameter disc 613 pressing force applying spring 62 right fiber holder.
621 Small-diameter disk 621a Holding cylindrical portion 622 Large-diameter disk 623 Pressurizing spring

Claims (9)

A connector housing having a V-groove housing portion in which a refractive index matching film is housed and a pair of adapter portions, and a pair of optical fibers are held and detachably fitted to the adapter portions, and the tips of the fiber strands of the optical fibers In an optical fiber connector comprising a pair of fiber holders that contact the left and right surfaces of the refractive index matching film,
The V-groove housing part includes a sheet-like elastic pad; and
The fiber holder includes a pressing force applying spring for bringing the tip of the fiber strand of the fiber into contact with the refractive index matching film with a pressing force of 20 gf · cm or more and less than the maximum durable pressing force of the refractive index matching film. An optical fiber connector. The optical fiber connector according to claim 1, wherein the housing includes a protective cover portion that covers the adapter portion.   The fiber holder includes a large-diameter disk having a through-hole through which a coating portion of an optical fiber freely penetrates, a small-diameter disk having a press-fit hole in which the coating portion of the optical fiber is press-fitted, and the small-diameter from the large-diameter disk. The optical fiber connector according to claim 1, wherein the optical fiber connector is constituted by the pressing force applying spring that presses the disk in a direction in which the disk is separated.   The adapter portion includes a large-diameter cylindrical body having an outer locking claw that engages with the large-diameter disk of the fiber holder and a small-diameter cylindrical body having an inner locking claw that engages with the small-diameter disk of the fiber holder. The optical fiber connector according to claim 1, wherein the optical fiber connector is a double cylindrical body comprising: The optical fiber connector according to claim 2, wherein the protective cover portion is a substantially cylindrical cover portion having a holding plate that releasably holds an optical fiber covering portion at an end portion.   6. The optical fiber connector according to claim 5, wherein the holding plate is composed of two holding plate members joined by a hinge.   The optical fiber connector according to claim 1, wherein the connector housing is manufactured by molding plastic.   The optical fiber connector according to claim 1 or 3, wherein the fiber holder is manufactured by molding plastic. The optical fiber connector according to claim 1, wherein the refractive index matching film is an epoxy resin.

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