WO1997048991A2

WO1997048991A2 - Optical connector and fiber optic connecting method

Info

Publication number: WO1997048991A2
Application number: PCT/US1997/010627
Authority: WO
Inventors: Kenneth F. Bowes
Original assignee: Pennoptics, Inc.
Priority date: 1996-06-21
Filing date: 1997-06-20
Publication date: 1997-12-24
Also published as: AU4582197A; WO1997048991A3

Abstract

A connector includes a housing (12, 12', 12', 222), a channel extending through the housing (12, 12', 12', 222) and at least one collet assembly (14, 14', 156, 156', 267) mounted in the housing (12, 12', 12', 222). The at least one collet assembly (14, 14', 156, 156', 267) includes a collet (78, 78', 78', 184, 268) configured to move from a closed position in which an optical fiber (F, F') is held in the connector to an open position in which the optical fiber (F, F') is removable from the connector. The collet assembly (14, 14', 156, 156', 267) further includes a bias element (42, 42', 194, 290) configured to bias the collet (78, 78', 78', 184, 268) to the closed position. A method includes the steps of applying a pressure to a collet assembly (14, 14', 156, 156', 267) against a biasing force of a bias element (42, 42', 194, 290) to slidably move a collet (78, 78', 78', 184, 268) of the collet assembly (14, 14', 156, 156', 267) from a closed position to an open position, inserting an optical fiber cable (F, F') into the collet assembly (14, 14', 156, 156', 267) and releasing the pressure on the collet assembly (14, 14', 156, 156', 267) such that the collet (78, 78', 78', 184, 268) moves to the closed position under the force of the bias element (42, 42', 194, 290) to hold the optical fiber (F, F') cable in a connector.

Description

OPTICAL FIBER CONNECTOR AND METHOD OF CONNECTING OPTICAL FIBERS

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Provisional Application Serial No. 60/020,223, filed on

June 21, 1996, and entitled "Optical Fiber Termination

Device and Method", the disclosure of which is herein incorporated by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates generally to the field of optical fiber terminations and, more particularly, to a spring-biased, reusable optical fiber connector and optical fiber connecting method in which the connector does not have to be disassembled in order to insert or remove the optical fiber.

2. Description of the Prior Art

In recent years, fiber optic light transmission systems have come into increasing use. These systems are used not only to provide illumination but also for conveying data from one location to another. For such data conveyance, a light source is modulated with data to be transmitted. The data is transmitted through an optical fiber cable and is recovered at the other end of the optical fiber cable by a photo-sensitive detector. A typical optical fiber cable is formed by at least one optical fiber surrounded by a protective coating. The protective coating is typically formed by a buffer coating surrounding the optical fiber, a strength member surrounding the buffer coating and an outer coating or jacket surrounding the strength member.

With the increasing use of fiber optic systems, the need has developed for a termination or connector to connect segments of light-conductive optical fiber cables with minimum detriment to the optical transmission path. To achieve efficient light transfer between optical fiber cables, the optical fibers must be axially and angularly aligned to a high degree of precision. The spacing between the optical fibers is also important to maintain a good optical transmission path. The alignment and spacing requirements are exceedingly demanding due to the minute, micron-size diameter of typical optical fibers which are on the order of about 0.005 inch.

Various devices and methods have been developed to terminate or connect, including joining and splicing, optical fiber cables. In one known method, an adhesive, such as an epoxy-based material, is used to glue the optical fiber into a connector. While these adhesive containing connectors can provide accurate positioning of the optical fiber, one disadvantage is that they require precise application and subsequent curing of the adhesive. Additionally, once the optical fiber has been glued into the connector, the connector cannot be reused.

As an alternative to adhesive based connectors, mechanical clamping connectors have been developed. In some prior art mechanical connectors, a pliable material, such as lead, is crimped or compressed directly onto the optical fiber to secure the optical fiber to the connector. Such mechanical connectors can subject the optical fiber to an excessive holding pressure, causing breaking, damage and excess optical loss. Alternatively, an insufficient holding pressure can permit undesirable movement of the optical fiber in the connector. Further, once the optical fiber is crimped into the connector, the connector cannot be easily reused.

Another known mechanical connector is disclosed in United States Patent No. 4,812,006 to Osborn et al . In the Osborn et al . connector, a collet is slipped around the optical fiber and the collet is then pushed into a bore in the connector body. When the collet is fully inserted into the bore, a flange on the collet engages an inner bore in the connector body to permanently retain the collet in the connector body. While the Osborn et al . connector is adhesive-free, it is not easily reusable since the collet is permanently retained in the connector body.

United States Patent No. 4,515,434 to Margolin et al . discloses an optical fiber connector in which two separate terminal members are placed around the optical fiber and the rear end of the terminal members are snap fit into a ferrule member to hold the terminal members around the optical fiber. The connector can be disassembled and reassembled for reuse. With most known mechanical connectors, the connector cannot easily be reused. Additionally, in order to connect or disconnect the optical fiber, the connector must be substantially disassembled and reassembled.

Therefore, it is an object of the invention to provide a mechanical optical fil er connector which is adhesive-free. It is also an object of the invention to provide a mechanical optical fiber connector that is reusable. It is a further object of the invention to provide an optical fiber connector and method in which the connector need not be substantially disassembled to add or replace an optical fiber. It is additionally an object of the invention to provide an optical fiber connector which is economical to manufacture and easy to use.

SUMMARY OF THE INVENTION An optical fiber connector is provided for releasably holding an optical fiber. The connector includes a housing and at least one collet assembly mounted in the housing. The at least one collet assembly includes a collet configured to reversably move from a first position in which an optical fiber is held in the connector to a second position in which the optical fiber is removable from the connector. The collet assembly preferably includes a bias element configured to bias the collet to the first position. A method is provided for releasably holding an optical fiber cable in an optical fiber connector. The method includes the steps of moving a collet of a collet assembly from a closed position to an open position, inserting an optical fiber cable into the collet assembly and releasing the collet assembly such that the collet moves to the closed position under the force of a bias element to hold the optical fiber cable in the connector.

A complete understanding of the invention will be obtained from the following description when taken in connection with accompanying drawing figures wherein like reference characters identify like parts throughout. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a side, sectional view showing an optical fiber captivation scheme of the invention;

Fig. 2 is a side, sectional view of a collet of the invention in an open configuration; Fig. 3 is an end view of the collet shown in Fig.

2 of the drawings;

Fig. 4 is a side, sectional view of a collet sleeve of the invention;

Fig. 5 is a side, sectional view of an optical fiber connector of the invention attached to an optical fiber cable;

Fig. 6 is a side, sectional view of a second optical fiber connector of the invention showing two optical cables spliced together; Fig. 7 is a side, sectional view of a third optical fiber connector of the invention attached to an optical fiber cable; and

Figs. 8A-8C show a fourth optical fiber connector of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom" and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. The term "connector" is used herein to refer generally to optical fiber terminations which can be used, for example, for connecting, splicing, terminating or joining optical fibers.

The structure of the optical fiber connectors of the invention will be discussed first prior to the description of the operation of these optical fiber connectors. An optical fiber captivation scheme of the invention is generally shown in Fig. 1 of the drawings. The captivation scheme includes a housing 12 having a spring-biased collet assembly 14 mounted in the housing 12. The housing 12 is preferably formed by two split housing half sections which are connected together in conventional manner to form the housing 12. The housing 12 has a first end 16 and a second end 18, with a bore or channel 20 extending longitudinally through the housing 12. The channel 20 includes a first channel section 24, a second channel section 26 and a third channel section 28. The first channel section 24 includes an annular shoulder 30. The third channel section 28 includes an inner annular shoulder 32, an outer annular shoulder 34 and a substantially funnel-shaped tapered end channel 36. The first channel section 24, second channel section 26 and third channel section 28 define a collet assembly chamber m the housing 12 in which the collet assembly 14 is mounted. The housing 12 can be made of any suitable material, such as plastic or metal. The collet assembly 14 includes a substantially cylindrical, hollow plunger 40, a bias element 42, a flexible collet 78 and a collet sleeve 46. The plunger has a first end 48, a second end 50, a first plunger section 52 and a second plunger section 54. The second plunger section 54 has a smaller outside diameter than the first plunger section 52 such that an annular shoulder 56 is formed between the first plunger section 52 and the second plunger section 54. The plunger 40 is substantially hollow and includes a first plunger cavity 60 having a tapered end channel 62 and a second plunger cavity 64 having engagement members 66 , such as notches, formed in the sidewall of the second plunger cavity 64. Additionally, the plunger 40 may have an annular pressing flange 68 located on the first end 48 of the plunger 40. The first plunger section 52 preferably has an outer diameter of about 0.180-0.185 inch and the second plunger section 54 preferably has an outer diameter of about 0.123-0.125 inch. The first plunger cavity has a diameter of about 0.065 inch.

The bias element 42, such as a spring, has a first end 72 and a second end 74. The first end 72 of the bias element 42 surrounds the second plunger section 54 and abuts the annular shoulder 56 on the plunger 40. The second end 74 of the bias element 42 abuts the annular shoulder 30 m the first channel section 24 of the housing 12. Thus, the plunger 40, and hence the collet assembly 14, is biased outwardly from the housing 12. The bias element 42 preferably has a free length of about 0.600 inch, a compressed length of about 0.210 inch, an inside diameter of about 0.120 inch and an outside diameter of about 0.159 inch.

As shown in Figs. 1-3 of the drawings, the collet 78 has a first end 80 and a second end 82. The collet 78 has a first, substantially cylindrical section 84 having a collet bore 86 and a second, expandable section 88. A plurality of engagement elements 90, such as barbs, are located on the outer surface of the first collet section 84 adjacent the first end 80 of the collet 78. The second collet section 88 is formed by two expandable legs 92, with each leg 92 having a longitudinally oriented, substantially V-shaped groove 94. The legs 92 are movable from an open position, as shown in Fig. 2 of the drawings, to a closed position, as shown in Fig. 1 of the drawings. A ramp 96 may be located on the outer surface of each leg 92. A collet flange 98 is located at the outer end of each leg 92.

As shown in Fig. 1 of the drawings, the first end 80 of the collet 78 is received in the second plunger cavity 64 and is held in place by the engagement elements 90 of the collet 78 which engage the engagement members 66 of the second plunger cavity 64. The bias element 42 surrounds the collet 78 in the first channel section 24. The collet 78 is preferably made of elastomeric material, such as nylon, having a preferred length of about 0.300 inch. The second collet section 88 has a length of about 0.150 inch. The first collet section has an outer diameter of about 0.72 inch with the engagement elements 90 having a height of about 0.11 inch from the outer surface of the first collet section 84. The ramps 96 have a height of about 0.005 inch. The walls of the V-shaped groove 94 are about 0.002 inch.

As shown in Fig. 4 of the drawings, the collet sleeve 46 has a substantially cylindrical body 104, a central passage 106 and an annular flange 108. As shown in Fig. 1 of the drawings, the collet sleeve 46 is positioned with the cylindrical body 104 slidably carried in the second channel section 26 and the annular flange 108 located in the third channel section 28. The collet sleeve 46 is preferably made of stamped metal, such as brass, having an intrinsic draft angle on the inner diameter. The collet sleeve 46 preferably has a length of about 0.192- 0.196 inch, an outer diameter of about 0.100 inch, an inner diameter of about 0.080 inch and a maximum draft of about 0.112 inch. The annular flange 108 has an outer diameter of about 0.141 inch.

Fig. 1 of the drawings shows an optical fiber cable C with an optical fiber F having an end face E held m the housing 12. The insertion and removal of the optical fiber cable C from the housing 12 is discussed herembelow.

An optical fiber connector of the invention utilizing the captivation scheme shown in Fig. 1 of the drawings is generally designated 114 m Fig. 5 of the drawings. The same reference numbers used in Fig. 1 of the drawings are used to indicate like elements in Fig. 5 of the drawings, with a prime (') symbol used to designate the elements of the connector 114. The connector 114 includes a housing 12' having a spring-biased collet assembly 14' . The housing 12' is preferably formed by two mirror image housing halves which may be connected together to form the housing 12' . The housing 12' includes a first channel section 24', a second channel section 26' and a third channel section 28' . The first channel section 24' , second channel section 26' and third channel section 28' define a collet assembly chamber in the housing 12' m which the collet assembly 14' is mounted. The third channel section 28' of the connector 114 differs from that of the connector 10 in that a tapered end channel 36' of the third channel section 28' is dimensioned smaller than the tapered end channel 28 of the connector 10, thereby producing a substantially rectangular channel portion 116 adjacent the tapered end channel 36' in the third channel section 28' .

As shown m Fig. 5 of the drawings, a ferrule

118, preferably made of ceramic, is attached to the second end 18' of the housing 12' in conventional manner. The ferrule 118 has a substantially cylindrical body with an optical fiber passage 120 extending longitudinally through the ferrule 118. The passage 120 includes a tapered entry portion 122 located at the end of the ferrule 118 ad_jacent the second end 18' of the housing 12' . The tapered entry portion 122 substantially aligns with the tapered end channel 36' of the housing 12' . The ferrule 118 has a first end 124 and a second end 126 As will be discussed herembelow, an optical fiber cable C having an optical fiber F with an end face E may be removably held in the connector 114.

A second embodiment of the connector of the invention, specifically designed to splice together two optical fibers, is generally designated 130 m Fig. 6 of the drawings. The connector 130 includes a housing 132 having a longitudinal channel 134 extending therethrough. The housing 132 is preferably formed by two longitudinally oriented housing halves which may be connected in conventional manner to form the housing 132. The longitudinal channel 134 includes a first collet assembly chamber 136 on the right side of the housing 132, as shown in Fig. 6, a second collet assembly chamber 136' on the left side of the housing 132 and a ferrule chamber 138 located between the first and second collet assembly chambers 136, 136' . Since the first and second collet assembly chambers 136, 136' are structurally identical, only the first collet assembly chamber 136 will be described in detail. The corresponding elements of the second collet assembly chamber 136' are designated by the same reference numerals as those of the first collet assembly chamber 136 but include a prime (') mark.

The first collet assembly chamber 136 includes a first channel section 140, a second channel section 142 and a third channel section 144. The first channel section 140 includes an annular shoulder 146 formed between the first channel section 140 and the second channel section 142. The third channel section 144 includes an inner annular shoulder 148, an outer annular shoulder 150 and a tapered end channel 152.

A first collet assembly 156 is located m the first collet assembly chamber 136 and a second collet assembly 156' is located in the second collet assembly chamber 136' . Since the first and second collet assemblies 156, 156' are structurally identical, only the first collet assembly 156 will be described in detail. The corresponding elements of the second collet assembly 156' are designated with a prime (') mark.

The first collet assembly 156 includes a plunger 158 having a first end 160, a second end 162, a first plunger section 164 and a second plunger section 166. An annular shoulder 168 is located between the first and second plunger sections 164, 166. A pressing flange 170 is located on the first end 160 of the plunger 158. The plunger 158 further includes a first plunger cavity 174 and a second plunger cavity 176. The first plunger cavity 174 includes a tapered end channel 178. The second plunger cavity 176 may include engagement members, such as notches, in the sidewall of the second plunger cavity 176.

The first collet assembly 156 includes a collet 184 having a first end 186 and second end 188, with the first end 186 of the collet 184 preferably having engagement elements configured to engage the engagement members in the second plunger cavity 176. The collet 184 is structurally the same as the collet 78 described hereinabove. A bias element 194 surrounds the collet 184 in the first channel section 140 and extends between the annular shoulder 146 and the second plunger section 166 to bias the plunger 158 outwardly of the housing 132.

A collet sleeve 198 having a substantially cylindrical body 200 and an outer annular flange 202 is mounted in the housing 132 with the cylindrical body 200 slidably received in the second channel section 142 and the annular flange 202 located in the third channel section 144. A ceramic ferrule 204 is located in the ferrule chamber 138. The ferrule 204 has a longitudinal channel 206 with a tapered entry portion 208, 208' located at opposed ends of the ferrule 204.

In Fig. 6 of the drawings, a first optical fiber cable C having an optical fiber F with an end face E is shown held in the first collet assembly 156 and a second optical fiber cable C having a second optical fiber F' with an end face E' is shown held in the second collet assembly 156' . Operation of the connector 130 is discussed hereinbelow.

A third embodiment of the connector of the invention is generally designated 220 in Fig. 7 of the drawings. The connector 220 includes a housing 222 having a first end 224 and a second end 226. The housing is preferably formed by two longitudinal housing halves connected together. A longitudinal channel 228 extends through the housing 222 and includes a first channel section 230 and a second channel section 232, with the second channel section 232 having a larger inside diameter than the first channel section 230. A ferrule 234 having a first end 236 and a second end 238 is mounted in the housing 222, with the first end 236 of the ferrule 234 inserted into the second channel section 232 of the housing 222.

The ferrule 234 has a longitudinal passage 240 with a first passage portion 242 and a second passage portion 244. A shoulder 246 is formed between the first and second passage portions 242, 244. The second passage portion 244 includes a tapered end channel 248, an inner shoulder 250 and an outer shoulder 252.

An annular outer sleeve 256 is located in the first passage portion 242 of the ferrule 234. The annular outer sleeve 256 has a first end 258 and a second end 260 and surrounds a collet sleeve 262. The collet sleeve 262 includes a cylindrical body 264 and an annular flange 266. The annular flange 266 includes an inner side which abuts the second end 260 of the outer sleeve 256 and an outer side which abuts the annular shoulder 246 located between the first and second passage portions 242, 244.

A collet assembly 267 includes a collet 268 and a plunger 270. The collet 268 is structurally the same as the collet 78 described above and has a first end 272 and a second end 274 with an expandable section located adjacent the second end 274 of the collet 268. The plunger has a first end 276, a second end 278, a pressing flange 280 formed on the first end 276, a first plunger cavity 282 having a tapered end channel 284 and a second plunger cavity 286. The second plunger cavity 286 may include engagement members, such as notches, which engage engagement elements, such as barbs, on the collet 268 m similar manner as described above. A bias element 290 surrounds the collet 268, with a first end 292 of the bias element 290 abutting the first, inner end 258 of the outer sleeve 256 and a second end 294 of the bias element 290 abutting the second end 278 of the plunger 270.

A fourth embodiment of the connector of the invention is generally designated 300 in Figs. 8A-8C. The structure of the connector 300 is similar to the connector 114 shown in Fig. 5 of the drawings and discussed above. Therefore, the same reference numbers are used to identify like elements, with a double prime mark ('') used to indicate the elements of the connector 300.

The connector 300 is structurally similar to the connector 114. However, the connector 300 does not include a collet sleeve surrounding the collet 78'' . Instead, the collet 78'' is slidable in, and directly contacts, the sidewall 302 of the second channel section 26'' . In the embodiment shown in Figs. 8A-8C of the drawings, the inner annular shoulder 32'' and the sidewall 302 of the second channel section 26'' form a substantially sharp interface 304. Alternatively, the interface 304 could be tapered to permit easier sliding of the collet 78' ' into and out of the second channel section 26'' . Additionally, the connector 300 differs from the connector 114 in that the housing 12' ' includes a ferrule mounting cavity 306 formed in the housing 12' ' adjacent the tapered end channel 36' ' . The first end 124' ' of the ferrule 118' ' is mounted in conventional manner in the ferrule mounting cavity 306. The operation of the connector 300 is discussed herembelow. Operation of the optical fiber connectors using the optical fiber captivation scheme of the invention will now be described. Looking first at the captivation scheme shown in Fig. 1 of the drawings, to assemble the collet assembly 14, the collet sleeve 46 is slipped onto the first end 80 of the collet 78 and slid forwardly toward the second end 82 of the collet 78. The bias element 42 is then slipped onto the first end 80 of the collet 78 and the collet first end 80 is pushed into the second plunger cavity 64 until the engagement elements 90 on the collet 78 engage the engagement members 66 in the second plunger cavity 64. The collet 78, collet sleeve 46 and bias element 42 are thus firmly connected to the plunger 40. The collet assembly 14 is then placed into one of the housing halves, as shown in Fig. 1 of the drawings. The other housing half is then attached to the first housing half to form the housing 12.

To prepare the optical fiber cable C, the outer protective coatings of the optical fiber cable C are removed to expose a length of the optical fiber F. The end face E of the fiber may be prefinished prior to being inserted into the housing 12 or may be finished after assembly. To insert the optical fiber F into the housing 12, the plunger 40 is pushed forward into the housing 12, i.e., to the left as shown in Fig. 1 of the drawings, by applying pressure to the pressing flange 68. As the plunger 40 moves to the left, the collet 78 is pushed forward such that the second end 82 of the collet 78 moves from a first or closed position, as shown m Fig. 1 of the drawings, to a second or open position, as shown in Fig. 2 of the drawings. When the collet 78 is pushed forward, the collet sleeve 46 surrounding the collet 78 will move forward until the annular flange 108 contacts the outer annular shoulder 34 of the third channel section 28. This prevents any further forward movement of the collet sleeve 46. However, the collet 78 may continue to slide forward through the collet sleeve 46 and expand into the tapered end channel 36 until the expanded legs 92 of the collet 78 abut the walls of the tapered end channel 36.

With the collet 78 thus moved from a closed to an open position, the optical fiber F is inserted into the first end 48 of the plunger 40 and through the first plunger cavity 60. The tapered end channel 62 of the first plunger cavity 60 helps direct the optical fiber F into the collet bore 86, through the collet 78 and into the third channel section 28 of the housing 12. The tapered walls of the tapered end channel 36 help direct the optical fiber F out of the second end 18 of the housing 12. The optical fiber cable C is preferably pushed into the first plunger cavity 60 until the end face of the optical fiber cable C substantially abuts the walls of the tapered end channel 36.

When the pressure is released from the plunger 40, the bias element 42 forces the plunger 40 outwardly of the housing 12, drawing the second end 82 of the collet 78 back into the collet sleeve 46, i.e., to the right as shown in Fig. 1 of the drawings. As the second end 82 of the collet 78 moves to the right, the collet sleeve 46 is drawn back into the second channel section 26 until the annular flange 108 of the collet sleeve 46 abuts the inner annular shoulder 32 of the third channel section 28. As the collet 78 continues to move to the right, the two legs 92 of the collet 78 are drawn together to capture the optical fiber F in the V-shaped grooves 94. The V-shaped grooves 94 will slightly deform around the optical fiber F and provide a holding resistance over the length of the second collet section 88. The ramps 96 on the outer surface of the collet 78 aid in closing the second collet section 88 onto the optical fiber F. The optical fiber F is thus firmly held in the housing 12 by the biasing force of the bias element 42 pressing outwardly on the plunger 40. An important aspect of the invention is that the optical fiber F is captured and held in place substantially by friction, which is controlled by the length of the second collet section 88. This is a substantial improvement over prior optical connectors which rely on compression of the optical fiber in the connector. Such compression results in high optical losses from the pressure (microbending optical losses) and "creep" in the resilient material which causes movement of the fiber.

To remove the optical fiber cable C from the housing 12, the plunger 40 is again pushed into the housing 12 to open the second end 82 of the collet 78, thus releasing the grip of the second collet section 88 on the optical fiber F. The optical fiber cable C can then simply be pulled to the right out of the plunger 40 to withdraw the optical fiber cable C from the housing 12. A different optical fiber cable can then be inserted into the housing 12 as described above. Thus, the captivation scheme of the present invention provides a non-adhesive, reusable optical fiber termination or connector in which the connector does not have to be disassembled and reassembled in order to insert or remove an optical fiber cable from the connector. Operation of the connector 114 shown in Fig. 5 of the drawings is similar to that described hereinabove. To insert an optical fiber cable C into the connector 114, the plunger 40' is pressed inwardly, i.e., to the left, to open the second end 82' of the collet 78', as described above. The legs 92' of the collet 78' expand into the third channel section 28' adjacent the tapered end channel 36' . The collet sleeve 46' moves forwardly until the annular flange 108' of the collet sleeve 46' abuts the outer annular shoulder 34' . This prohibits any further forward movement of the collet sleeve 46' .

The optical fiber F is inserted into the first end 48' of the plunger 40' and is guided into the collet bore 86' by the tapered end channel 62' . The optical fiber F is pushed forwardly and is guided by the tapered end channel 36' in the third channel section 28' into the tapered entry portion 122 of the ferrule passage 120. When the pressure on the plunger 40' is released, the bias element 42' forces the plunger 40' outwardly, thus drawing the collet sleeve 46' and second end 82' of the collet 78' toward the right to close the legs 92' of the collet 78' around the optical fiber F to hold the optical fiber F in the connector 114.

If the end face E of the optical fiber F has been prefinished, the optical fiber end face E should be positioned flush with the outer, second end 126 of the ferrule 118. This can be done by placing the ferrule second end 126 on a flat surface and then pressing and releasing the plunger 40' . Pressing and releasing the plunger 40' causes the optical fiber F to move forwardly in small increments. This causes the optical fiber F to feed forwardly until it hits the flat surface. The amount of forward movement is controlled by the dimensions of the third channel section 28' , the bias element 42' and the collet 78' . Alternatively, the optical fiber F can extend beyond the second end 126 of the ferrule 118 and can be finished in conventional manner, such as by flat polishing, PC polishing, angled PC finishing, etc.

To remove the optical fiber cable C from the connector 114, the plunger 40' is again pushed inwardly to open the collet 78' . The optical fiber F and optical fiber cable C can then be pulled out of the connector 114 and a new optical fiber cable inserted. Releasing the pressure on the plunger 40', as described above, will thus hold the new optical fiber in the connector 114.

The connector 130 shown in Fig. 6 of the drawings is specifically designed to splice a first optical fiber cable C and a second optical fiber cable C together and operates in similar manner to the connector described above. Prior to installing the optical fiber cables C, C into the connector 130, a section of the outer protective coating of each optical fiber cable C, C is removed to expose a length of the respective optical fibers F, F' . The end face E, E' of each optical fiber F, F' is then prepared by either cleaving or polishing. The finished end face E, E' of each optical fiber F, F' is thus at an approximate predetermined length from the end face of the outer protective coating. To splice the two optical fiber cables C, C together, the plunger 158 of the first collet assembly 156 is pushed into the housing 132 to open the second end 188 of the collet 184, as was described above. The optical fiber F is then pushed into the second plunger cavity 176, through the collet 184, through the tapered end channel 152 of the third channel section 144 and the tapered entry portion 208 of the ferrule 204 into the ferrule channel 206. When the plunger 158 of the first collet assembly 156 is released, the collet 184 is pulled back into the collet sleeve 198 to hold the first optical fiber F in the connector 130. The end face E of the optical fiber F is thus positioned approximately midway in the ferrule channel 206 and substantially perpendicularly to the longitudinal axis of the ferrule channel 206.

With the first optical fiber cable C thus securely held in the first collet assembly 156, the plunger 158' of the second collet assembly 156' is depressed to open the second end 188' of the collet 184' , as shown on the left side of Fig. 6 of the drawings. The second optical fiber cable C is then inserted into the plunger 158' of the second collet assembly 156' , with the optical fiber F' extending through the collet 184' and into the ferrule 204 until the end face E' of the second optical fiber F' substantially abuts the end face E of the first optical fiber F. The pressure is then released on the plunger 158 to contract the second end 188' of the collet 184' around the second optical fiber F' to securely hold the second optical fiber F' in the connector 130.

Alternatively, the second optical fiber F' can be inserted into the second collet assembly 156' until the end face E' of the second optical fiber F' is near the end face E of the first optical fiber F. By repeatedly pressing and releasing the plunger 158' of the second collet assembly 156' , the second optical fiber F' is indexed to the right by small increments until the end face E' of the second optical fiber F' abuts the end face E of the first optical fiber F. After this occurs, further pressing and releasing on the plunger 158' does not cause any negative effects since the forward movement of the second optical fiber F' is stopped as soon as the end face E' of the second optical fiber F' meets the resistance of the end face E of the first optical fiber F. To remove either one or both of the optical fibers C, C from the connector 130, a selected one of the plungers 158, 158' is pushed inwardly to open that plunger's collet 184, 184' and the selected optical fiber cable C, C pulled free from the connector 130. In the same manner as discussed above, a new optical fiber cable can then be inserted into the connector 130. Operation of the connector 220 shown in Fig. 7 of the drawings is similar to that discussed above with respect to the connector 114 shown in Fig. 5 of the drawings. The plunger 270 is pushed inwardly of the housing 222, i.e., to the left as shown in Fig. 7 of the drawings. As the plunger 270 moves to the left, the collet 268 moves through the collet sleeve 262 so that the second end 274 of the collet 268 opens. Unlike the previous connector embodiments, the collet sleeve 262 is held in place between the annular shoulder 246 and the outer, second end 260 of the outer sleeve 256. Thus, the collet sleeve 262 does not move forwardly with the collet 268. The collet 268 is free to move to the left until the second collet end 274 abuts the outer shoulder 252 of the second passage portion 244 of the ferrule 234. This prohibits any further forward movement of the collet 268. The optical fiber cable C is inserted into the plunger 270 and the optical fiber F guided through the collet passage 269 and into the tapered end channel 248 of the second passage portion 244. The pressure on the plunger 270 is then released to cause the bias element 290 to force the plunger 270 outwardly, thus pulling the second end 274 of the collet 268 back into the collet sleeve 262 to hold the I optical fiber F in position. The end face E of the optical fiber F can be positioned as was discussed above with respect to the connector 114 of Fig. 5. To remove the optical fiber cable C from the connector 220, the plunger 270 is again pressed into the housing 222 to open the second end 274 of the collet 268, thus releasing the optical fiber cable C.

Operation of the connector 300 shown in Figs. 8A- 8C of the drawings is similar to that described above with respect to the connector 114 shown in Fig. 5 of the drawings. To insert an optical fiber cable C into the connector 300, the plunger 40'' is pressed inwardly into the housing 12'' . This moves the collet 78' ' forwardly through the second channel section 26' ' to the open position shown in Fig. 8B of the drawings. As shown in Fig. 8C of the drawings, the optical fiber F is inserted into the first end 48' ' of the plunger 40'' and is guided into the collet bore 86' ' by the tapered end channel 62' ' . The optical fiber F is pushed forwardly and is guided by the tapered end channel 36'' in the third channel section 28' ' into the tapered entry portion 122' ' of the ferrule passage 120'' . When the pressure on the plunger 40' ' is released, the collet 78'' is drawn back into the second channel section 26' ' to capture and hold the optical fiber F. The end face E of the optical fiber F can be positioned in the connector 300 in similar manner as described above with respect to the connector 114.

Thus, as described above, the present invention provides a relatively inexpensive, non-adhesive, reusable optical fiber connector and captivation scheme in which an optical fiber can be added or removed from the connector without any disassembly of the connector.

While embodiments of the invention have been described in detail herein, it will be appreciated by those skilled in the art that various modifications and alternatives to the embodiments could be developed in light of the overall teachings of the disclosure. For example, while the preferred connector embodiments discussed above directly engage the optical fiber, the connector could alternatively be configured to grasp one of the outer protective coatings of the optical fiber cable rather than the optical fiber itself. Accordingly, the particular arrangements are illustrative only and are not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof .

Claims

I claim :

1. An optical fiber connector for releasably holding an optical fiber, the connector comprising: a housing; and at least one collet assembly mounted in the housing, wherein the at least one collet assembly includes a collet configured to reversably move from a first position in which an optical fiber is held m the connector to a second position in which the optical fiber is removable from the connector.

2 The connector as claimed in claim 1, wherein the collet assembly further includes a bias element configured to bias the collet to the first position.

3. The connector assembly as claimed in claim 1, wherein the housing includes a channel, the channel including a first channel section having an annular shoulder, a second channel section adjacent the first channel section and a third channel section adjacent the second channel section, the third channel section having a tapered end channel .

4. The connector as claimed in claim 1, including a collet sleeve located in the housing, with the collet slidably carried in the collet sleeve.

5. The connector as claimed in claim 1, wherein the collet includes a first collet section and a second collet section, the second collet section including a pair of opposed legs.

6. The connector as claimed in claim 1, wherein the collet assembly includes a plunger having a first plunger cavity and a second plunger cavity, with a first end of the collet received in the second plunger cavity to connect the collet to the plunger.

7. The connector as claimed m claim 1, wherein the housing has a first end and a second end and the connector includes a ferrule extending from the second end of the housing.

8. The connector as claimed in claim 1, wherein the housing has a first end and a second end and the channel includes : a first collet assembly chamber located ad_jacent the first end of the housing; a second collet assembly chamber located ad_jacent the second end of the housing; and a ferrule chamber located between the first and second collet assembly chambers, wherein the connector includes: a first collet assembly located m the first collet assembly chamber; a second collet assembly located in the second collet assembly chamber; and a ferrule located in the ferrule chamber, wherein each collet assembly includes a collet configured to move from a first position in which an optical fiber is held m the collet assembly to a second position m which the optical fiber is removable from the collet assembly, each collet assembly including a bias element configured to bias the collet of each collet assembly to the first position.

9. The connector as claimed in claim 2, wherein the at least one collet assembly includes: a hollow plunger, wherein the collet is attached to the plunger and wherein the bias element is configured to bias the plunger outwardly from the housing to bias the collet to the first position.

10. The connector as claimed in claim 5, wherein each leg includes a ramp located on an outer surface of the leg.

11. The connector as claimed in claim 5, wherein the legs include a V-shaped groove configured to hold the optical fiber when the collet is m the first position.

12. The connector as claimed m claim 5, including at least one engagement element located on an outer surface of the first collet section.

13. The connector as claimed in claim 7, wherein the ferrule includes a ferrule passage, with a collet sleeve located in the ferrule passage.

14. The connector as claimed in claim 7, wherein the ferrule includes a passage having a tapered entry portion.

15. The connector as claimed in claim 3, wherein the at least one collet assembly includes: a hollow plunger slidably carried m the first channel section, with the collet attached to the plunger; and a collet sleeve located m the housing, with the collet slidably carried in the collet sleeve, and wherein the bias element is configured to bias the plunger to move the collet to the first position.

16. The connector as claimed in claim 13, including an outer sleeve surrounding the collet sleeve.

17. The connector as claimed in claim 13, wherein the ferrule passage includes a first passage portion, a second passage portion and an annular shoulder located between the first and second passage portions.

18. The connector claimed in claim 17, wherein the collet assembly includes: a hollow plunger, wherein the collet is attached to the plunger and wherein the bias element abuts the plunger and is configured to bias the plunger outwardly from the housing; and an outer sleeve surrounding the collet sleeve.

19. An optical fiber connector for releasably holding an optical fiber, the connector comprising: a housing; a channel extending through the housing, the channel including a first channel section, a second channel section and a third channel section; and a collet assembly carried in the housing, the collet assembly including: a substantially hollow plunger slidably carried in the first channel section; a collet attached to the plunger, the collet reversably movable from a first position in which an optical fiber is held in the connector to a second position in which the optical fiber is removable from the connector; and a bias element configured to bias the plunger outwardly of the housing to bias the collet to the first position.

20. A method of releasably holding an optical fiber cable in an optical fiber connector, comprising the steps of: moving a collet of a collet assembly from a closed position to an open position; inserting an optical fiber cable into the collet assembly; and releasing the collet assembly such that the collet moves to the closed position under the force of a bias element to hold the optical fiber cable in the connector.

21. An optical fiber connector for releasably holding an optical fiber, comprising: means for moving a collet of a collet assembly from a closed position to an open position; means for inserting an optical fiber cable into the collet assembly; and means for releasing the collet assembly such that the collet moves to the closed position under the force of a bias element to hold the optical fiber cable in the connector.