JPS6057046B2 - optical fiber connector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a connector for connecting ends of optical fibers that transmit light, and more particularly to an optical fiber connector that does not use a connecting fluid to reduce connection losses.

More particularly, the present invention provides an optical system with elastic means for elastic adjustment of the contact pressure of the surface of one end of one fiber core against the surface of one end of a second fiber core. Concerning how to use fiber connectors. Systems that do not use a coupling fluid to reduce coupling losses require actual end-to-end contact of the optical fibers.

Ideal optical fiber coupling involves positioning the carefully crafted square-cut end surfaces of the two fibers so that their longitudinal axes are aligned. For on-site connections, such as those where connections are made by physically touching the ends of the fibers, extreme care must be taken in handling to avoid excessive pressure between the ends of the fiber end surfaces in contact. is necessary. Some pressure is required to bring the surfaces into full contact and minimize loss due to interlocking. However, if the pressure is too high, the end faces will deform and losses will increase.
This type of optical fiber connector is described in U.S. Pat.

However, this connector has significant typical drawbacks. First, there is no built-in control scheme for the end-to-end contact pressure of the optical fibers used. As a result, the contact pressure must be absorbed primarily by the elasticity of the fibers themselves. If large tolerances are allowed in the fiber dimensions, the ends of the fibers must be carefully adjusted within the connector. This is a difficult and time-consuming task, and is not always successful. Therefore, coupling fluids are often used to reduce coupling losses, and in fact the use of such fluids is implied in the Dalgleci patent. A second drawback of such known devices is the lack of flexibility between the mated parts, resulting in misalignment.

A single misaligned part causes deformation and shifts the fiber ends.

Misalignments in non-flexible devices are often caused by seemingly innocuous influences, such as dust particles. As a result, a loss in coupling efficiency occurs. Another drawback of the prior art device is that it does not have a separate centering device to accurately align and clamp the ends of the two fibers in place after they have been brought into contact within the connector.

In known devices, there is a built-in expectation that the ends will be accurately positioned when brought into contact within the connector;
This is often not achieved. There is no precise mechanism to place the edges correctly. The optical fiber connector of the present invention provides exposed core end contact of two optical fibers for transmitting light.

This connector provides a built-in device for controlling the contact pressure between the ends of the optical fibers in contact. The cone and O-ring system provides resilient flexibility between the mated portions of the connector. A separate centering device allows for final fiber end alignment after the ends have been brought into contact inside the connector. The combination of these features provides highly efficient optical fiber splicing. The connector of the present invention includes two retainers, one for each of the two exposed fiber core ends to be brought into contact therewith.

Each retainer is fitted into one of the two ends of a symmetrical coupling sleeve that includes a symmetrical centering device for the ends of the two fibers. Each retainer has means for receiving a cable passage sleeve containing one of the fiber ends. Each cable passage sleeve includes an integrally mounted cable retention means, preferably a gripper, extending axially from the cable passage sleeve and adapted to be inserted into the gripper passage of each retainer. . O-rings between each connector component, i.e. cable passage sleeve, retainer, and coupling sleeve, provide a resilient and flexible connection system capable of elastically absorbing high fiber contact pressures between the ends. is obtained. In addition to the O-ring, each interface between the mated connector parts consists of a conical surface.

That is, cable retention means extending from each cable passage sleeve contact a conical surface within the first end of each retainer. At the second end of each retainer there is a conical hole (referred to as a centering cone) which contacts a conical centering means inside the coupling sleeve. 0
- The ring and cone work together to form a resilient and highly efficient coupling system.

The body of the optical fiber connector centering device of the present invention consists of a pair of symmetrical cones that are axially disposed within the coupling sleeve, with the apexes of each cone pointing away from each other.

A centering passage within the centering device is defined by a hole to receive and bring the ends of the fiber into contact. The ends of the fibers contact the midpoint of the centering device, and each fiber end is introduced through one apex of the cone. At the midpoint of the centering device between the centering channels there is a triangular channel boat defined by a triangular cross section. There is an access boat perpendicular to and extending into this passage boat, through which the clamping spring is inserted after the fiber ends have been brought into contact.
The spring for the clamp is attached to the fiber 2 inside the passage boat.
The exposed core ends are pressed against the walls of the triangle to precisely position the ends of the fibers after contact, further reducing coupling losses. For a better understanding of the features and advantages of the invention, reference will now be made to the accompanying drawings.

A partially cut-away sketch of a preferred embodiment of the optical ◆fiber● connector of the present invention is shown in FIG.
Two outer sheaths 10 (bottom left and top right in FIG. 1) enclose the ends of two optical fiber cores 12 for contact within the connector.

The core of an optical fiber is transparent glass or a synthetic material, such as plastic, and is usually coated with a material of lower refractive index to enhance the reflection of light. Inner sheath 14 is encased between outer sheath 10 and fiber core 12 as shown on both fibers. In a preferred embodiment of the connector of the present invention, there are five different parts:
i.e. two cable passage sleeves 16, two retainers 1
8, and one symmetrical coupling sleeve 20.

In FIG. 1, the lower left cable passage sleeve 16
and the lower left retainer 18 are both shown unattached, and the upper right cable passage sleeve 16
, upper right retainer 18 and coupling sleeve 20 are shown together.

When assembled, the coupling sleeve 20 is placed between the two retainers and includes a centering device 22, which provides for actual fiber core end contact. Each retainer 18 has a first end 24 and a second end 26.

The first end has an internal grasper passageway 28 with a radially symmetrical set of resilient cable retaining channels extending axially from and integrally attached to the cable passage sleeve 16. It is adapted to receive a gripper 30. The gripper passage 28 has a cylindrical mouth 32 that surrounds a flared cone 34 inside the retainer. conical mouth 32
and the expanded cone 34 has an expanded space 36 between them.
, at which the grippers 30 are unfolded to remove the fiber cable as described below. Grip device 1
At the second end 26 of 8 there is a penetrating sleeve 38, which contains an internal centering cone 40.

The centering cone 40 is adapted to receive the opposing cone 42 of the centering device 22 in a tight-fitting manner. Centering cone 40 also forms the mouth of a core passageway 44, which extends through the exposed core end of the optical fiber. The core passageway 44 contacts a wide cable passageway 46, which contains a portion of the fiber cable inner sheath 14. The cable passage 46 further abuts a conical insertion hole 48, which forms the inner surface of the flared cone 34 mentioned above. Two optical
Contacting the exposed ends of the fibers can be achieved with a coupler in the following manner.

First, a certain length of the outer sheath 10 is peeled off from a predetermined length of cable to expose a part of the inner sheath 14 to form an optical fiber cable. to make. A shorter length of the inner sheath 14 is then removed from the end of the cable, exposing the fiber core 12. Next, a set of grippers 30
A resilient O-ring 50 is mounted over and in contact with mating edge 52 of cable passage sleeve 16. The gripper 30 is inserted into the gripping passage 28 and resiliently compressed until the gripper reaches the expanded space 36. At this point, the beveled edge 54 of the grasper contacts the circular mouth 32 of the grasping passage 28 and begins to flare outward as it is pushed further into the enlarged space 36. However, O-ring 50 exerts a force tending to pull grasper 30 back from expanded space 36;
It is pushed back towards the gripper passage 28, where the gripper is elastically compressed. To insert the fiber cable produced above, the cable passage sleeve 16 is moved toward the retainer 18 so as to retain the retainer 30 within the flared portion.
The force of the 0-ring must be overcome by pressing it down manually. In the next step, the inner sheath 14 is attached to the gripper 3.
0 until it reaches the cable passageway 46. The exposed core 14 is then passed through the core passageway 44;
It passes through centering circle 840 and extends slightly beyond the end of penetrating sleeve 38 . The pressure of cable passage sleeve 16 against retainer 18 is then relieved, the O-ring is expanded, and gripper 30 is partially withdrawn from expanded space 36. The gripper is then elastically compressed to clamp the inner sheath 14 of the fiber cable. Removal of the fiber cable involves pressing the cable passage sleeve 16 against the retainer 18, compressing the O-ring and causing the gripper 30 to assume the expanded position again within the expanded space 36. It is achieved by doing so. After mating cable passage sleeve 16 and retainer 18, the retainer is ready to be mated with coupling sleeve 20.

Connecting sleeve 20 includes a centering device 22 that includes a resilient pair of inverted cones 42 . The inverted cone 42 is located axially within the coupling sleeve 20 and has an apex defined by a conically flared mouth 58 oriented away from each other. A centering passage 60 within the centering device 22 receives and brings into contact the end cores 12 of the optical fibers, each core 12 being introduced therein via the apex of one inverted cone 42. . The end of the coupling sleeve 20 has an internally flanged resilient snap lip 62 which has an insertion hole 5 for receiving the penetration sleeve 38 of the two retainers 18.
6 is defined. Penetrating sleeve 38 includes a rectangular shaped groove 64 into which an O-ring 66 is placed. Next, the penetration sleeve 38 is inserted into the insertion hole 56 of the coupling sleeve, and the elastic snap-fitting edge 6
2 into the groove 64 until it fits onto the O-ring 66. In this way, the centering cone 40 in the penetrating sleeve 38 is located adjacent to the fitted internal inverted cone 42, and a double conical clearance space 68 is formed. This clearance space 68 is longer than the length required for contact, and can absorb elastic deformation when using a core that would otherwise cause contact deformation due to high pressure. The conical surfaces of the cone 40 and inverted cone 42 for centering the three expanded cones, and the elastic properties of the O-rings 50 and 66 effectively flex the core end of the optical fiber. An elastic pressure absorbing system is provided for contacting.

FIG. 2 shows another embodiment of the cage of the invention.

In this embodiment, the cage has four different parts:
It consists of an outer retainer sleeve 70, a coil spring 72, an inner retainer sleeve 74, and a separate penetrating sleeve 76. Inner retainer sleeve 74 has a pair of sliding cams 78 that project through slots 80 in outer retainer sleeve 70 to allow sleeve 74 to slide within sleeve 70.

Sleeve 74 defines a centering passage 82, which has a conical opening 84 similar to the first embodiment. Also like the first embodiment, the flared cone 84 and the conical mouth 86 define a flared space 88 therebetween. The outer retainer sleeve 70 has an inner seat 90 against which a coil spring 72 is supported and exerts a force against the inner retainer sleeve 74. Clamp in the gripper 30. To insert the fiber cable, the sliding cam 78 is pushed against the spring 72 and
The gripper 30 is connected to the conical opening 8 of the sleeve 74 of the internal retainer.
6 in the opposite direction and enter the expanded space 88. Next. to loosen the cam 78 so that the coil spring 72 snaps onto the sloped edge 54 of the gripper 30.
the inner retainer sleeve 74 is pushed together and around the inner cable sheath 14.
When the penetrating sleeve 76 is inserted into the coupling sleeve insertion hole 56, the fiber core 12 contacts the interior of the centering device 22 as described above. In this latter embodiment, the O-rings 52 and 66 are replaced by a coil spring 72. An annular groove 92 is provided at the interface between the outer retainer sleeve 70 and the penetrating sleeve 76 so that the snap edges 62 of the interlocking sleeve are resiliently engaged. An enlarged view of the centering device 22 of the present invention is shown in FIG.
It is shown in FIG.

This centering device is located intermediately inside the coupling sleeve 20 and has two legs 96 in addition to the previously mentioned inverted cone 42.
It includes a clamping spring 94 with a clamping spring, a peripheral mounting groove 98 for positioning the clamping spring, and a port 100 for putting in and taking out. A triangular passage boat 102 is intermediate the centering passage 60 in which the ends of the fiber cores 12 are brought into contact. After bringing the fiber core ends into contact, the two legs 96 of the clamping spring 94
is inserted into the triangular passage boat 102 so that each leg presses one of the two core ends against two adjacent sides of the triangular passage boat 102 as shown in FIG. This results in a very simple but efficient mechanism for aligning fibers in contact. Figures 5 and 6
The figure shows a front view and a side view of another embodiment of the clamping spring. Other shapes can also be used. The optical fiber coupler of the present invention is for contacting the exposed core ends of two fiber cables within a closed passageway.

Such a coupler can be used as a photoconductor in an information signal transmission system. Typically, an electrical signal is converted to a light signal by a photovoltaic converter, which is then transmitted over an optical fiber cable, which can then be converted into electrical pulses by a photodiode at the receiving end.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sketch of a preferred embodiment of the optical fiber connector of the present invention;
The first of the two cable passage sleeves and the first of the two retainers are removed, and the second cable passage sleeve, the second retainer, and the coupling sleeve are assembled. The condition is shown.

Claims (1)

[Claims] 1. Consisting of two retainers, two cable passage sleeves, and a symmetrical connecting sleeve, the two retainers are arranged for each of the ends of the two fibers to be connected. each retainer having means for receiving a cable passage sleeve at a first end, each retainer having a penetration for insertion into a symmetrical connecting sleeve at two ends; two cable passing sleeves, one for each of the ends of the two fibers to be connected.
each cable passage sleeve has an integrally attached cable retention means extending in the axial direction thereof, the cable retention means being insertable into the first end of the retainer. , the symmetrical connecting sleeve is connected to one of the retainers.
means at each end for receiving a pair of said penetrating sleeves, the coupling sleeve bringing the ends of the optical fiber into end-to-end contact so that the coupling sleeve has a means for receiving an intermediate portion of the retainer containing the fiber ends; 1. An optical fiber connector for bringing exposed core ends of two optical fibers into contact for transmitting light, the connector comprising centering means for bringing the exposed core ends of two optical fibers into contact. 2. The centering means has a centering device having a pair of axially disposed symmetrical inverted cones including apexes defined by conically flared apertures, each of the apertures being respectively aligned with respect to the other. facing away from each other, the mouths leading to respective centering passages that extend toward each other through the inverted cone and contact triangular passage ports located midway therebetween. and the ends of the heart are brought into contact,
The optical fiber according to claim 1, wherein the ends of the core are held by clamping means.
connector. 3. Each of the retainers further has a core passageway in contact with a widened centering cone adapted to receive one of the inverted cones of the centering device. , a two-sided conical clearance space is defined by the centering cone and the inverted cone, respectively, and is created by end-to-end pressure between the two contacting optical fiber cores. The optical fiber according to claim 2 is adapted to absorb elastic deformation caused by
Fiber connector. 4. said retainer means for receiving cable passage sleeves comprising a gripper passage; said integrally attached cable retaining means of each of said two cable passage sleeves comprising a gripper; 4. A connector according to claim 1, wherein said means for receiving said penetrating sleeve of said retainer is an insertion hole having an internally flanged resilient snap rim. 5. The clamping means comprises a clamping spring;
Claim 2 or 3, wherein the leg has legs extending into and out of the port and is adapted to push the end of the contacted fiber core against an adjacent wall within the triangular passage port. Connector described in Section 3. 6 each gripper passage of the retainer has a conical mouth;
5. The connector of claim 4, wherein said mouth surrounds a flared cone to define a flared space within each retainer and is adapted to receive said retainer. 7. Each of the retainers further has a cable passage for receiving an inner sheath of a bare fiber cable, the cable passage contacting at one end a conical insert located inside the flared cone. 7. A connector according to claim 4 or 6, wherein the other end of the cable passage is in contact with the core passage. 8. A connector according to any one of claims 1 to 7, wherein the retainer, cable passage sleeve and coupling sleeve are mated, and an O-ring is located between the coupling members. 9 the retainer includes an outer retainer sleeve, an inner retainer sleeve inside the outer retainer sleeve, a coil spring in contact with an inner seat inside the outer retainer sleeve;
and another member comprising a penetrating sleeve extending outwardly from the outer sleeve, the inner sleeve and the penetrating sleeve fitting together within the outer retainer sleeve to define an expanded space. 2. The connector of claim 1, wherein the coil spring is located intermediate the inner seat of the outer sleeve and the inner sleeve to exert a force on the inner sleeve.