JP4059606B2 - Optical connector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical connector capable of fixing and holding an optical fiber without using an adhesive, and more particularly to an optical connector having a ferrule and a ferrule that presses the ferrule against an adapter or the like using a spring member.
[0002]
[Prior art]
In the field of optical communications, optical fibers are used in optical transmission systems, and optical connectors are used to connect terminals of various optical communication devices and optical fibers extending from the optical communication devices.
As the optical connector, a cylindrical member having a through hole for an optical fiber for accurately positioning the optical fiber, that is, a ferrule, is used so that the end faces of the optical fibers to be connected come into contact with each other with high precision. For example, in an adapter, the ferrules are guided by a sleeve and elastically contacted to connect the optical fibers. At the time of connection, the ferrule and the optical fiber are elastically contacted backward from the connection end surface of the optical fiber. Receiving compressive force for. Therefore, the optical connector needs to withstand this compressive force and hold the optical fiber. Furthermore, in order to connect the optical fibers by making the ferrules elastically contact each other, it is also necessary that the ferrules move elastically within a certain range.
[0003]
By the way, in optical communication, a quartz optical fiber is generally used, and various optical connectors for connecting the quartz optical fiber have been proposed and used. In these optical connectors, the ferrule is used to connect the quartz optical fiber with low loss. At that time, when assembling an optical connector for connection using a ferrule, it is common to fix the quartz optical fiber to the optical connector by adhering and fixing the quartz optical fiber to the ferrule using an epoxy adhesive or the like. Is.
[0004]
However, according to this bonding method, it takes time to cure the adhesive, leading to a reduction in work efficiency when constructing an optical communication system. For this reason, a heating device is used to shorten the curing time of the adhesive, but the heating device itself is not only necessary for connecting the optical fiber, but also requires time for preheating the heating device, Even if the curing time is shortened, a curing time of about 30 minutes to 1 hour is required. Furthermore, since a power source is required for heating, connection work may be restricted at construction sites such as indoor wiring sites in buildings.
[0005]
Therefore, in order to increase the work efficiency of the optical fiber connection work, an optical connector that does not use an adhesive is desired, and various optical connectors have been proposed.
For example, in Japanese Patent Publication No. 5-47081, a spring member is arranged behind the ferrule so that the ferrules are elastically connected to each other, and the collet chuck is disposed at a position away from the ferrule so as to hold the optical fiber during the connection. An optical connector device that uses and holds an optical fiber has been proposed.
However, in this apparatus, since the ferrule and the collet chuck are separated from each other, the optical fiber is likely to buckle due to the compressive force at the time of connection, and there is a concern about deterioration loss of optical energy. Further, since the ferrule and the collet chuck are separated from each other, the optical connector itself becomes long, and it is not possible to sufficiently cope with a demand for miniaturization expected in the future.
[0006]
In addition, optical connectors that mechanically hold an optical fiber without using an adhesive have been proposed in Japanese Patent Laid-Open Nos. 7-181344 and 10-062650. However, all of these require a plurality of parts to mechanically fix the optical fiber, and the structure is more complicated than the adhesive type optical connector that fixes the optical fiber by bonding, and the increase in cost is not hindered. There was a problem.
[0007]
By the way, in recent years, plastic optical fibers have begun to be used for LAN (LOCAL AREA NETWORK) and inter-device connection in place of such quartz optical fibers. Even when an optical connector designed for a quartz optical fiber is used as an optical connector for a plastic optical fiber, a method of adhering and fixing the optical fiber using an adhesive to a ferrule is used in the same manner as the quartz optical fiber. For this reason, problems in connection occurred as in the case of the quartz optical fiber.
Therefore, development of an optical connector that can be easily constructed has been awaited when an optical transmission system is constructed.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide an optical connector that can hold an optical fiber with a small number of parts without using an adhesive for fixing the optical fiber and is easy to construct.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a housing, a hollow body holding member disposed inside the housing, an optical fiber holding groove or an optical fiber holding hole, and the optical axis direction of the optical fiber from the tip. An optical fiber holding member disposed on the inside of the hollow body holding member, the optical fiber holding member including a front portion having a tapered surface on the outer peripheral surface and a tubular rear portion having an optical fiber through hole. An annular member that is fitted into a fiber holding member and is slidably contacted with the tapered surface of the front part, and tightens the front part as it goes in the distal direction of the front part, and the inner side of the hollow body holding member , wherein the step provided in the hollow body holding member disposed between the annular member, by biased against the annular member from the step of the hollow body holding member, through said annular member There is provided an optical connector, characterized in that it comprises an elastic member tightening and pressing the forward portion Te.
[0010]
Here, the inside of the housing includes a ferrule having a through hole for an optical fiber and protruding forward,
The ferrule is in contact with the end surface of the front end of the front portion of the optical fiber holding member, and the light is transmitted through the annular member biased by the elastic member toward the front end of the front portion of the optical fiber holding member. It is preferable to press the fiber holding member against the ferrule.
Moreover, it is preferable that the said elastic member is a spring member inserted in the said optical fiber holding material, and arrange | positioned adjacent to the said annular member.
Furthermore, it is preferable that the front portion of the optical fiber holding member has two or more cuts from the front end of the front portion along the optical fiber optical axis direction.
[0011]
Here, the optical connector is preferably an optical fiber made entirely of a plastic material, or an optical fiber made of a plastic material for the outer layer, and the optical fiber holding member is preferably made of a resin material. .
Further, a step portion having an inner diameter is provided on the inner peripheral surface behind the hollow body holding member, and a protrusion corresponding to the change in the inner diameter is formed on the outer peripheral surface in the vicinity of the rear end portion of the optical fiber holding member. Preferably it is provided.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the optical connector of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
[0013]
FIG. 1 shows a cross-sectional view of an assembled optical connector 10 which is a preferred embodiment of the optical connector of the present invention.
The optical connector 10 mainly includes a ferrule 12, a housing 14, a hollow body holding member 16, an optical fiber holding member 18, an annular member 20, and a spring member 22, and a holder 24 so as to cover the housing 14. Is provided.
[0014]
Ferrule 12 is made for the optical fiber connection forward, that is, from a cylindrical portion 12a and a base 12b that protrudes in a direction (direction of arrow X in FIG. 1) having an end face F ₁ of the optical fiber F, the cylindrical portion 12a Has a ferrule through hole 26 that allows the optical fiber F to pass through along the cylindrical axis.
The base portion 12 b has an outer diameter that is larger than the outer diameter of the cylindrical portion 12 a, and forward protrusion is limited by the protrusion portion 14 a provided on the inner peripheral surface of the housing 14.
Further, the end surface 12c behind the base portion 12b of the ferrule 12 (the direction opposite to the arrow X in FIG. 1) is in contact with the front end surface 18a of the optical fiber holding member 18, as will be described later.
[0015]
Such a ferrule 12 allows the position of the optical fiber F to be accurately determined on the front end surface of the ferrule 12 by passing the optical fiber F through the ferrule through hole 26 from the rear, and is flush with the front end surface of the ferrule 12. End face processing (cutting and polishing) is performed so as to be in contact with the end face of another optical fiber via an adapter.
Note that the inner diameter of the ferrule through hole 26 is wide on the base 12b side and narrows forward. This is because the optical fiber F can be easily inserted and penetrated from behind.
[0016]
The housing 14 is a member that holds the ferrule 12 in a predetermined position and fixes a hollow body holding member 16 described later in a predetermined position.
A holder 24 for coupling with an adapter or a receptacle of an optical communication device is attached to the front outer periphery of the housing 14.
[0017]
The hollow body holding member 16 is a cylindrical hollow body member disposed at a predetermined position in the optical axis direction of the optical fiber F on the inner peripheral surface of the housing 14, and includes an optical fiber holding member 18, an annular member 20 and The spring member 22 is configured to be disposed inside the hollow body.
That is, the hollow body holding member 16 has a protrusion 16b provided on the outer periphery of the hollow body holding member 16 in the housing 14 in a state where the optical fiber holding member 18, the annular member 20 and the spring member 22 are arranged inside the hollow body. By being fitted into the notch 14 b provided, the housing 14 is fixed at a predetermined position.
Here, the position in the housing 14 of the notch 14b to which the protrusion 16b is fitted and coupled to the hollow body holding member 16 is a step provided on the inner peripheral surface of the hollow body holding member 16, as will be described later. The spring member 22 obtains a desired urging force by the portion 16a, and is configured at a position to urge the annular member 20 forward.
[0018]
Further, the hollow body holding member 16 has a stepped portion 16a and a stepped portion 16d on the inner peripheral surface, and as shown in the figure, the stepped portion 16a forms an inner peripheral surface 16c having a small inner diameter, and on the rear side thereof. The step 16d forms an inner peripheral surface 16e whose inner diameter is larger than the inner diameter of the region of the inner peripheral surface 16c.
Here, the reason why the inner diameter of the region of the inner peripheral surface 16e is larger than the inner diameter of the region of the inner peripheral surface 16c is the optical fiber holding member 18 described later by the step portion 16d at the boundary between the inner peripheral surface 16c and the inner peripheral surface 16e. This is to prevent the protrusion 18b provided on the outer peripheral surface in the vicinity of the rear end portion from freely moving forward, and as a result, the optical fiber holding member 18, the annular member 20, and the spring member 22 are held by the hollow body. This is to prevent the member 16 from easily falling off. By adopting a configuration in which the members or the like do not easily fall out in this way, it is possible to provide a structural member in which the optical fiber holding member 18, the annular member 20, and the spring member 22 are preliminarily incorporated in the hollow body holding member 16. The efficiency of optical fiber connection work at the site can be improved.
[0019]
As shown in FIGS. 2 and 3, the optical fiber holding member 18 is a member composed of a front portion 18c and a tubular rear portion 18d for fixing and holding the optical fiber F, and is formed of a resin material. By using a resin material, for example, it has a compression characteristic similar to that of a plastic fiber or the like, and does not make a scratch or a dent in the holding portion of the optical fiber F.
[0020]
Front portion 18c has two notches 18e along from the front tip surface 18a of the front portion to the optical fiber optical axis direction, to form the dividing member 18f ₁ and 18f _2. Dividing member 18f ₁ and 18f ₂ has an optical fiber holding groove 18 g ₁ and 18 g ₂ inwardly, taken to go to the rear of the optical axis of the optical fiber F (the opposite direction of the arrow X) divided member 18f ₁ and 18f ₂ The outer circumferential surface of the front portion 18c, that is, the outer circumferential surface of the dividing members 18f ₁ and 18f ₂ is tapered surfaces 18h ₁ and 18h ₂ whose outer circumference decreases toward the rear of the optical fiber optical axis. Is provided. Here, the cross-sectional shape of the optical fiber holding grooves 18g ₁ and 18g ₂ is a semicircular shape, but may be other shapes such as a triangular shape and a rectangular shape. Further, the cross-sectional area of the hole formed by the optical fiber holding grooves 18g ₁ and 18g ₂ when the split members 18f ₁ and 18f ₂ are joined is equal to or smaller than the cross-sectional area of the optical fiber F.
Furthermore, the front portion 18c of the optical fiber holding member 18 of the present embodiment has two cuts 18e, but the present invention is not limited to this, and has three cuts or four cuts. Also good.
[0021]
On the other hand, the tubular rear portion 18d has an optical fiber through hole 18i along the central axis. Further, a protruding portion 18j is provided on the outer peripheral surface in front of the tubular rear portion 18d, and the optical fiber holding member 18 is brought into the hollow body holding member 16 by slidingly contacting the inner peripheral surface 16c of the hollow body holding member 16. Positioned with high accuracy. Further, a protrusion 18b is provided on the outer peripheral surface near the rear end of the optical fiber holding member 18, and the optical fiber holding member 18 is formed by the protrusion 18b and the step 16d of the hollow body holding member 16 as described above. Is restricted from moving forward.
[0022]
The annular member 20 is in sliding contact with the tapered surface 18h ₁ and 18h ₂ are fitted into the front portion 18c of the optical fiber holding member 18, dividing member 18f ₁ and 18f spaced apart in the front portion 18c toward the forward tip of the forward portion 18c _This is a tightening member that is tightened in the direction of the optical fiber holding grooves 18g ₁ and 18g ₂ so that ₂ is close. The inner diameter of the annular member 20 is smaller than the outer diameter of the front tip portion when the separated divided members 18f ₁ and 18f ₂ are joined to each other, and the annular member 20 comes out of the front tip portion of the optical fiber holding member 18. It is configured not to fall off.
[0023]
The spring member 22 is an elastic member that is located behind the annular member 20 in the gap with the optical fiber holding member 18 inside the hollow body holding member 16 and is fitted into the front portion 18c.
The spring member 22 transmits a biasing force biased from the stepped portion 16 a of the hollow body holding member 16 to the annular member 20. Thereby, the annular member 20 presses and tightens the front portion 18c. In addition, as for the hollow body holding member 16, the position of the level | step-difference part 16a is preset so that a desired urging | biasing force (compression force) may be given with respect to the annular member 20, as mentioned above.
Thereby, the optical fiber F located in the optical fiber holding grooves 18g ₁ and 18g ₂ is fixedly held.
In the present embodiment, the spring member 22 is used. However, in the present invention, the spring member 22 is not necessarily limited thereto, and may be a known elastic member that gives a predetermined urging force such as a rubber member.
[0024]
Front portion 18c of the present embodiment forms a split member 18f ₁ and 18f ₂ has a notch 18e, but in the present invention, not necessarily the front portion has a notch, for example, an optical fiber F to the central axis An elastically compressible frustoconical member having an optical fiber holding hole larger than the diameter and having a tapered surface similar to the front portion 18c of this embodiment is used for the front portion, and the annular member 20 is slid forward. A mechanism for holding the optical fiber F by narrowing the inner diameter of the optical fiber holding hole by fastening an elastically compressible frustoconical member may be used.
[0025]
In this embodiment, the optical connector includes the ferrule 12, but an optical connector that does not include the ferrule may be used. For example, an optical connector in which optical fibers are directly inserted into a sleeve provided in the adapter and the optical fibers are brought into contact with each other may be used.
Such an optical connector is used for an optical fiber made entirely of a plastic material, such as an all-fluorine plastic optical fiber, or an optical fiber whose outer layer is made of a plastic material, for example, a PCF in which the outer periphery of a quartz optical fiber is coated with a polymer material. It is preferably used for connection of (polymer clad fiber). Of course, it may be used for a conventional quartz optical fiber.
The optical connector of the present invention may be used not only for SC type optical connectors and FC type optical connectors, but also for LC type optical connectors and MU type optical connectors.
The optical connector 10 is configured as described above.
[0026]
Next, the operation and assembly of the optical connector of the present invention will be described based on the optical connector 10 described above.
First, the spring member 22 and the annular member 20 are arranged at a predetermined position in the hollow body holding member 16 together with the optical fiber holding member 18 in a state where the spring member 22 and the annular member 20 are fitted in the front portion 18 c of the optical fiber holding member 18. That is, since the spring member 22 and the annular member 20 are fitted in the front portion 18c, the optical fiber holding member 18 is inserted from the front of the hollow body holding member 16, and the protrusion 18b of the optical fiber holding member 18 is protruded. While sliding in the region of the inner peripheral surface 16c whose inner diameter is smaller than the outer diameter of the portion 18b, the region 18b is inserted to the region of the rear inner peripheral surface 16e. As a result, the protruding portion 18b does not return to the front of the step portion 16d, and the optical fiber holding member 18 is disposed in the hollow body holding member 16.
Accordingly, the spring member 22 and the annular member 20 are also arranged at predetermined positions inside the hollow body holding member 16.
[0027]
At this time, the movable range of the optical fiber holding member 18 is also limited within a range in which the movement of the protrusion 18b is limited by the stepped portion 16d, but can move freely within this range.
On the other hand, the annular member 20, since the inner diameter of the annular member 20 is smaller than the outer diameter of the front tip portion at the time of bonding the partition member 18f ₁ and 18f ₂ of the front portion 18c to each other, light annular member 20 It will not fall out of the fiber holding member 18. Therefore, the spring member 22 does not come off the optical fiber holding member 18 and drop off.
Thus, since the spring member 22, the annular member 20, and the optical fiber holding member 18 are preliminarily incorporated in the hollow body holding member 16, and the components are maintained without falling off, the efficiency of the connection work at the construction site is improved. be able to. At this time, since the spring member 22 extends to a free length (is in a free length state), there is no fear that the optical fiber holding member 18 is tightened by the annular member 20, and the divided members 18 f ₁ and 18 f ₂ are sufficient. Are separated.
[0028]
Thereafter, the optical fiber F is inserted and penetrated from the tubular rear portion 18d of the optical fiber holding member 18, and the optical fiber F is further passed through the opening of the ferrule through hole 26 on the end surface of the base portion 12b of the ferrule 12, so that the ferrule 12 is passed. It penetrates and protrudes to the tip of the ferrule 12. Thereafter, the hollow body holding member 16 in which the ferrule 12, the spring member 22, the annular member 20, and the optical fiber holding member 18 are incorporated is covered with the housing 14 from the front, and is fixed at a predetermined position in the housing 14.
That is, the hollow body holding member 16 is fixed at a predetermined position by fitting the protrusions 16 b provided on the outer peripheral surface into the notches 14 b provided on the inner peripheral surface of the housing 14. At the same time, the ferrule 12 has a rear end surface 12c of the ferrule 12 abutting against the front end surface 18a of the optical fiber holding member 18, while the base portion 12b of the ferrule 12 is formed by a protrusion 14a provided on the inner peripheral surface of the housing 14. The forward protrusion is limited.
[0029]
At this time, the spring member 22 receives a biasing force directed forward from the stepped portion 16a, and pushes the annular member 20 slidably contacting the tapered surfaces 18h ₁ and 18h ₂ forward by this force. Further, the annular member 20 pushes the optical fiber holding member 18 forward and pushes the ferrule 12 forward with a predetermined urging force. Thereby, when connecting an optical fiber via an adapter or the like, the optical fiber can be elastically connected without causing damage such as buckling to the optical fiber by elastically bringing the ferrules into contact with each other.
[0030]
The annular member 20 is so pushed out forward by the biasing force of the spring member 22, clamping the front part 18c, as a result, the optical fiber F is held fixed tightened by division member 18f ₁ and 18f _2. Since the optical fiber holding member 18 uses a resin material, the holding portion of the optical fiber F will not be damaged or dented.
After the housing 14 is mounted, the end face processing of the optical fiber F is performed, and a holder 24 for coupling with an adapter or a receptacle of an optical communication device is mounted.
In this way, the optical connector 10 is assembled.
[0031]
Next, the optical connector 10 shown in FIG. 1 was created, and the holding power and optical transmission loss of the optical fiber F were examined.
The used optical fiber F is a plastic fiber having an outer diameter of 565 μm, and is formed by optical fiber holding grooves 18g ₁ and 18g ₂ when the divided members 18f ₁ and 18f ₂ of the optical fiber holding member 18 are joined to each other. The cross section of the groove was circular with an inner diameter of 565 μm, and the inner diameter of the optical fiber through hole 26 of the ferrule 12 was 580 μm. Further, the urging force by which the spring member 22 presses the ferrule 12 forward through the annular member 20 and the optical fiber holding member 18 was set to 400 g, and the optical fiber F was held by the optical fiber holding member 18. As the housing 14 and the holder 24, an SC type optical connector conventionally used for an optical connector of quartz optical fiber is used.
[0032]
At this time, the holding force that the optical connector 10 holds the plastic optical fiber is 1 kg or more, and the urging force that the optical connector 10 presses the ferrule forwardly inserts the ferrule into the adapter or the receptacle to make the optical fiber elastic. It exceeded the compressive force required when connecting to.
[0033]
Further, optical transmission loss degradation due to the compressive stress received by the optical fiber when the optical connector 10 holds and fixes the optical fiber was examined using an LED (laser light emitting diode) light source that emits light having a wavelength of 850 nm. The optical fiber examined was a perfluorinated plastic optical fiber. As a result, no loss deterioration due to compressive stress was observed.
[0034]
Furthermore, using an optical connector having the configuration of the present invention at both ends of an optical fiber, an LED light source that emits light having a wavelength of 850 nm is obtained with a coupling loss of a 2 m long fluoroplastic optical fiber optically polished at both ends. Evaluated using. As a result, a good coupling loss result equal to or higher than that of an optical connector using a conventional adhesive was obtained.
[0035]
As described above, the optical connector of the present invention can elastically connect optical fibers using adapters and receptacles, and also has sufficient optical fiber holding power, no loss in optical transmission, and no coupling loss. It is clear that it is equivalent or better than conventional.
[0036]
The optical connector of the present invention has been described in detail above. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the spirit of the present invention. is there.
[0037]
【The invention's effect】
As described above in detail, the optical connector of the present invention does not use an adhesive for fixing the optical fiber and can be mechanically held with a small number of parts. Connection work itself becomes easy and work efficiency improves. Therefore, the optical fiber can be connected in a short time.
Furthermore, the coupling loss of the plastic optical fiber using the optical connector of the present invention was confirmed to be equal to or higher than that of the conventional one.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of an embodiment of an optical connector of the present invention.
FIG. 2 is an external view showing an optical fiber holding member, an annular member, and a spring member of the optical connector shown in FIG.
3 is a cross-sectional view of the optical fiber holding member viewed in the direction of the arrow from the line AA shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Optical connector 12 Ferrule 12a Cylindrical part 12b Base part 14 Housing 14a, 16b, 18b Protrusion part 14b Notch part 16 Hollow body holding member 16a, 16d Step part 16c, 16e Inner peripheral surface 18 Optical fiber holding member 18a Front front end surface 18c Front Portion 18d annular rear member 18e notches 18f ₁ , 18f ₂ split members 18g ₁ , 18g ₂ optical fiber holding grooves 18h ₁ , 18h ₂ tapered surface 18i optical fiber through hole 18j projecting portion 20 annular member 22 spring member

Claims (7)

A housing;
A hollow body holding member disposed inside the housing;
An optical fiber holding groove or an optical fiber holding hole, and a front part having a tapered surface on the outer peripheral surface, the outer circumference of which decreases from the tip along the optical axis direction of the optical fiber, and a tubular rear part having an optical fiber through hole An optical fiber holding member disposed inside the hollow body holding member,
An annular member that fits into the optical fiber holding member and is arranged in sliding contact with the tapered surface of the front portion, and tightens the front portion as it goes in the distal direction of the front portion;
The inner side of the hollow body holding member is disposed between the step provided on the hollow body holding member and the annular member, and is biased from the step of the hollow body holding member to the annular member. And an elastic member that presses and tightens the front portion through the annular member. The inside of the housing includes a ferrule having a through hole for an optical fiber and protruding forward,
The ferrule is in contact with the end surface of the front end of the front portion of the optical fiber holding member, and the light is transmitted through the annular member biased by the elastic member toward the front end of the front portion of the optical fiber holding member. The optical connector according to claim 1, wherein a fiber holding member is pressed against the ferrule. The optical connector according to claim 1, wherein the elastic member is a spring member that is fitted into the optical fiber holding member and disposed adjacent to the annular member. The optical connector according to claim 1, wherein the front portion of the optical fiber holding member has two or more cuts along the optical fiber optical axis direction from the front end of the front portion. The optical connector according to any one of claims 1 to 4, which is used for an optical fiber made entirely of a plastic material or an optical fiber whose outer layer is made of a plastic material. The optical connector according to claim 1, wherein the optical fiber holding member is made of a resin material. On the inner peripheral surface at the rear of the hollow body holding member, a step portion having an inner diameter is provided, and a protrusion corresponding to the change in the inner diameter is provided on the outer peripheral surface near the rear end of the optical fiber holding member. The optical connector according to claim 1.

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