COMPRESSABLE MPO CONNECTOR

Description

TECHNICAL FIELD

[0001] The present disclosure relates to fiber optic connectors and, more particularly, to a ferrule assembly for a pushable multiple fiber push on connector.BACKGROUND

[0002] Optical fibers are useful in a wide variety of applications, including the telecommunications industry for voice, video, and data transmissions. In a telecommunications system that uses optical fibers, there are typically many locations where fiber optic cables that carry the optical fibers connect to equipment or other fiber optic cables. To conveniently provide these connections, optical connectors are often provided on the ends of fiber optic cables. The process of terminating individual optical fibers from a fiber optic cable is referred to as "connectorization." Connectorization can be done in a factory, resulting in a "pre-connectorized" or "pre-terminated" fiber optic cable, or the field (e.g., using a "field-installable" connectors).

[0003] Many different types of optical connectors exist. In environments that require high density interconnects and / or high bandwidth, such as data centers, multi-fiber optical connectors are the most widely used. One example is the multi-fiber push on (MPO) connector, which incorporates a mechanical transfer (MT) ferrule and standardized according to TOA-604-5 and IEC 61754-7. Another example is the MTP ®< connector, which is a particular type of MPO connector (MTP ®< is a trademark of US Conec Ltd.). These connectors can achieve a very high density of optical fibers, which reduces the amount of hardware, space, and effort to establish a large number of interconnects.

[0004] However, conventional MPO connectors are too large to be pushed through ducts used in fiber optic cable distributions, for example, ducts having an inside diameter of less than 10mm and, in some aspects, ducts having an inside diameter of 5.5mm. Therefore, it may be desirable to provide an MPO connector having a ferrule assembly that can terminate a multiple fiber cable and be pushed through a duct and a housing that can be coupled with the ferrule assembly in the field after the terminated multiple fiber cable is pushed through a duct.

[0005] An example fiber optic connector capable of mating with conventional connectors is disclosed in the EP patent application No. EP1020745, comprising a ferrule for terminating the optical fibers and a ferrule adapter couplable with the ferrule to convert a female fiber optic connector into a male fiber optic connector (or vice versa).SUMMARY

[0006] A fiber optic connector is disclosed in any one of claims 1-11.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a perspective view of a conventional a fiber optic connector; FIG. 2 is an exploded perspective view of the conventional fiber optic connector of FIG. 1; FIG. 3 is a perspective view of an exemplary fiber optic connector in accordance with various aspects of the disclosure; FIG. 4 is an exploded perspective view of the fiber optic connector of FIG. 3; FIG. 5 is a perspective cross-sectional view of the fiber optic connector of FIG. 3; FIG. 6 is a side cross-sectional view of the fiber optic connector of FIG. 3; FIG. 7 is a top cross-sectional view of the fiber optic connector of FIG. 3; FIG. 8 is a perspective view of the ferrule assembly of the fiber optic connector of FIG. 3; FIG. 9 is a perspective view of the ferrule assembly of FIG. 8 with a protective cap; FIG. 10 is a perspective view of the ferrule assembly and housing of the fiber optic connector of FIG. 3; FIG. 11 is a perspective view of the ferrule and ferrule adapter of the fiber optic connector of FIG. 3; FIG. 12 is a front view of the ferrule and ferrule adapter of FIG. 11; FIG. 13 is a perspective partial cutaway view of the ferrule and ferrule adapter of FIG. 11; FIG. 14 is a perspective view of another exemplary fiber optic connector in accordance with various aspects of the disclosure; FIG. 15 is a top cross-sectional view of the fiber optic connector of FIG. 14; FIG. 16 is an enlarged top cross-sectional view of a portion of the fiber optic connector of FIG. 14; FIG. 17 is a perspective view of the ferrule assembly, housing, and retaining clip of the fiber optic connector of FIG. 14; FIG. 18 is a perspective view of the ferrule assembly of the fiber optic connector of FIG. 14; FIG. 19 is a front view of the ferrule assembly of FIG. 18; FIG. 20 is a perspective view of the ferrule of the fiber optic connector of FIG. 14. DETAILED DESCRIPTION OF EMBODIMENTS

[0008] As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents, unless the context clearly dictates otherwise.

[0009] FIGS. 1 and 2 illustrate a conventional fiber optic connector 100 (also referred to as an "optical connector" or simply "connector") in the form of an MTP ®< connector, which is a particular type of MPO connector (MTP ®< is a trademark of US Conec Ltd.).

[0010] As shown in FIG. 1, the connector 100 may be installed on a fiber optic cable 112 ("cable") to form a fiber optic cable assembly 114. The connector includes a ferrule 116, a housing 118 received over the ferrule 116, a slider 120 received over the housing 118, and a boot 122 received over the cable 112. The ferrule 116 is spring-biased within the housing 118 so that a front portion 124 of the ferrule 116 extends beyond a front end 126 of the housing 118. Optical fibers (not shown) carried by the cable 112 extend through bores / micro-holes 128 in the ferrule 116 before terminating at or near an end face 130 of the ferrule 116. The optical fibers are secured within the ferrule 116 using an adhesive material (e.g., epoxy) and can be presented for optical coupling with optical fibers of a mating component (e.g., another fiber optic connector; not shown) when the housing 120 is inserted into an adapter, receptacle, or the like.

[0011] As shown in FIG. 2, the connector 100 also includes a ferrule boot 132, a guide pin assembly 134, a spring 136, a retention body 138 (also referred to as a crimp body), and a crimp ring 140. The ferrule boot 132 is received in a rear portion 142 of the ferrule 116 to help support the optical fibers extending to the ferrule bores 128 (FIG. 1). The guide pin assembly 134 includes a pair of guide pins 144 extending from a pin keeper 146. Features on the pin keeper 146 cooperate with features on the guide pins 144 to retain portions of the guide pins 144 within the pin keeper 146. When the connector 100 is assembled, the pin keeper 146 is positioned against a back surface of the ferrule 116, and the guide pins 144 extend through pin holes 148 (FIG. 1) provided in the ferrule 116 so as to project beyond the front end face 130.

[0012] Both the ferrule 116 and guide pin assembly 134 are biased to a forward position relative to the housing 118 by the spring 136. More specifically, the spring 136 is positioned between the pin keeper 146 and a portion of the crimp body 138. The crimp body 138 is inserted into the housing 118 when the connector 100 is assembled and includes latching arms 150 that engage recesses 152 in the housing 118. The spring 136 is compressed by this point and exerts a biasing force on the ferrule 116 via the pin keeper 146. The rear portion 142 of the ferrule defines a flange that interacts with a shoulder or stop formed within the housing 118 to retain the rear portion 142 within the housing 118.

[0013] In a manner not shown in the figures, aramid yarn or other strength members from the cable 112 are positioned over an end portion 154 of the crimp body 138 that projects rearwardly from the housing 118. The aramid yarn is secured to the end portion 154 by the crimp ring 140, which is slid over the end portion 154 and deformed after positioning the aramid yarn. The boot 122 covers this region, as shown in FIG. 1, and provides strain relief for the optical fibers by limiting the extent to which the connector 100 can bend relative to the cable 112. To insert the connector into an adapter or receptacle, the connector 100 is configured such that a user grasps the boot 122 and pushes the connector 100 into the adapter or receptacle, thereby allowing the housing to be fully inserted for proper engagement / mating with the adapter or receptacle. To disengage the connector 100 from an adapter or receptacle, the user grasps and pulls the slider 120, which may be biased by springs 156 (FIG. 2) relative to the housing 118, away from the adapter or receptacle. This way pull forces are transferred directly to the housing 118 (rather than the cable 112) to disengage the housing 118 from the adapter or receptacle.

[0014] Referring now to FIGS. 3-13, an exemplary fiber optic connector 300 in accordance with various aspects of the disclosure is illustrated and described. The fiber optic connector 300 is in the form of an MPO connector. As shown in FIGS. 3-7, the connector 300 may be installed on a fiber optic cable 312 ("cable") to form a fiber optic cable assembly 314. The connector includes a ferrule 316 (e.g., a mechanical transfer (MT) ferrule), a housing 318 received over the ferrule 316, a shell 320 received over the housing 318, and a boot 322 received over the cable 312. The ferrule 316 is spring-biased within the housing 318 toward a front end 326 of the housing 318. Optical fibers 302 carried by the cable 312 extend through bores / micro-holes 328 in the ferrule 316 before terminating at or near an end face 330 of the ferrule 316. The optical fibers 302 may be secured within the ferrule 316 using an adhesive material (e.g., epoxy) and can be presented for optical coupling with optical fibers of a mating component (e.g., another fiber optic connector; not shown) when the housing 318 is inserted into an adapter, receptacle, or the like.

[0015] Although the drawings illustrate the ferrule 316 terminating six fibers of the multiple fiber cable 312, it should be appreciated that the ferrule 316 can be configured to terminate less than six fibers or more than six fibers of a multiple fiber cable. For example, in some aspects, the ferrule 316 may be configured to terminate twelve fibers of a multiple fiber cable.

[0016] The connector 300 also includes a pin clip 332, a ferrule adapter 334, a spring 336 (e.g., an oval spring), a retention body 338, and a crimp sleeve 340. As shown in FIGS. 5-7, when the connector 300 is assembled, the pin clip 332 is disposed at a rear end 342 (e.g., against a back surface) of the ferrule 316 to help support the optical fibers extending to the ferrule bores 328. The ferrule adapter 334 includes a pair of bores 335 configured to receive internal pins 344 extending from the ferrule 316 and a pair of channels 337 configured to receive external pins 366 extending from the pin clip 332. In some aspects, the bores 335 can be through bores. The pin clip 332 includes enlarged bore portions 331 configured to receive head portions 367 of the external pins 366 and narrowed neck portions 333 configured to cooperate with neck portions 369 and the head portions 367 of the external pins 366 to retain the head portions 367 of the external pins 366 within the pin clip 332. A portion 370 of each external pin 366 extending from the neck portion 369 is received in a respective one of the channels 337 of the ferrule adapter 334 and an external channel 317 of the ferrule 316. That is, each channel 337 of the ferrule adapter 334 and a respective one of the external channels 317 of the ferrule 316 cooperate to define a bore configured to receive the external pin 366. When the connector 300 is assembled, the internal pins 344 extend into bores 348 provided in the ferrule 316.

[0017] The ferrule 316, the ferrule adapter 334, and the pin clip 332 are biased to a forward position relative to the housing 318 by the spring 336. More specifically, the spring 336 is positioned between a rear facing surface of the pin clip 332 and a forward facing surface of the retention body 338. The retention body 338 includes two body halves 338a, 338b that have the same construction, including a latch member 380 and a catch 382 disposed on opposite lateral sides of the body halves 338a, 338b. Each of the body halves 338a, 338b also includes a pair of forward extending latching arms 350, and the latching arms 350 include outward extending protrusions 351 configured to engage a notch, recess, or opening 352 in a side wall of the housing 318 to couple the retention body 338 with the housing 318. Each of the body halves 338a, 338b may also include a circumferentially-extending groove 388 configured to receive a circumferential flange 341 extending radially outward from an outer surface of the crimp sleeve 340. The flange 341 may include one more flattened portions that prevent rotation of the crimp sleeve 340, and thus the cable 312 and fibers 302, relative to the retention body 338. Of course, altemative keying structures may be employed in place of the flattened portions. An inner support sleeve 304 may be inserted beneath the jacket of the cable 312 to protect the fibers 302 when the crimp sleeve 340 is crimped to the cable 312.

[0018] The retention body 338 is inserted into the housing 318 when the connector 300 is assembled, and the protrusions 351 of the latching arms 350 engage openings 352 in the side wall of the housing 318. The spring 336 is compressed by this point and exerts a biasing force on the ferrule 316 via the pin clip 332 and the ferrule adapter 334. The ferrule adapter 334 includes a flange configured to interact with a shoulder or stop formed within the housing 318 to retain the ferrule 316 and the ferrule adapter 334 within the housing 318. The boot 322 covers a rear portion of the retention body 338, as shown in FIG. 3, and provides strain relief for the optical fibers 302 by limiting the extent to which the connector 300 can bend relative to the cable 312.

[0019] To insert the connector into an adapter or receptacle, the connector 300 is configured such that a user grasps the boot 322 and pushes the connector 300 into the adapter or receptacle. Pins from a mating connector (not shown) at the adapter or receptacle are received in the bores delineated by cooperative alignment of the channels 337 of the ferrule adapter 334 and the external channels 317, thereby allowing the housing to be fully inserted for proper engagement / mating with the adapter or receptacle. To disengage the connector 300 from an adapter or receptacle, the user grasps and pulls the slider 320, which may be biased by springs 356 relative to the housing 318, away from the adapter or receptacle. This way, pull forces are transferred directly to the housing 318 (rather than the cable 312) to disengage the housing 318 from the adapter or receptacle.

[0020] FIG. 8 illustrates a ferrule assembly 310 configured to be pushed through a duct, for example a duct having an inner diameter less than 10mm and, in some cases, a duct having an inner diameter of 5.5mm. The ferrule assembly 310 includes the ferrule 316 terminating the plurality of fibers 302, the spring 336, and the crimp sleeve 340. As shown, the inner support sleeve 304 may be disposed beneath the jacket of the cable 312. Referring to FIG. 9, a protective cap 390 may be placed over the ferrule assembly 310 to protect the spring 336 and fibers 302. The cap 390 may include a circumferential groove configured to receive the flange 341 of the crimp sleeve 340 to couple the cap 390 with the crimp sleeve 340. The protective cap 390 can eliminate sharp edges and blunt faces to facilitate pushing through a duct.

[0021] Referring now to FIG. 10, after the ferrule assembly 310 is pushed through a duct to a connection location of a fiber distribution system, the boot 322 can be moved rearwardly over the ferrule assembly 310 and beyond the crimp sleeve 340. The ferrule adapter 334 and the pin clip 332 can be positioned about the fibers 302 at the rearward end of the ferrule 316, as best shown in FIGS. 5 and 7, and coupled with one another via the internal pins 344 and the external pins 366. The Then, the retention body halves 338a, 338b can be coupled together (e.g., snap-fit together) over the crimp sleeve 340 and spring 336, and the boot 322 can be moved forwardly over the rear portion of the retention body 338. The housing 318 is coupled with the retention body 338 via the cooperating protrusions 351 of the latching arms 350 and the openings 352 in the side walls of the housing 318. The shell springs 356 and shell 320 can then be coupled with the housing 318. The shell 320 may include a recessed portion 321 at a bottom inner surface and / or a top inner surface having a forward facing shoulder configured to engage a rearward facing shoulder of a projection 319 extending from a bottom outer surface and / or a top outer surface of the housing 318.

[0022] Referring now to FIGS. 14-20, an exemplary fiber optic connector 500 in accordance with various aspects of the disclosure is illustrated and described. The fiber optic connector 500 is in the form of an MPO connector. The connector 500 is similar to the connector 300 described above, but is slightly modified to eliminate the pin clip 332 and the internal pins 344. In the connector 500, the ferrule 516 and the ferrule adapter 534 cooperate to define pin holes 577 for receiving external pins (not shown).

[0023] The connector 500 may be installed on a fiber optic cable 512 ("cable") to form a fiber optic cable assembly 514. The connector includes a ferrule 516 (e.g., a mechanical transfer (MT) ferrule), a housing 518 received over the ferrule 516, a shell 520 received over the housing 518, and a boot 522 received over the cable 512. The ferrule 516 is spring-biased within the housing 518 toward a front end 526 of the housing 518. Optical fibers 502 carried by the cable 512 extend through bores / micro-holes 528 in the ferrule 516 before terminating at or near an end face 530 of the ferrule 516. The optical fibers 502 may be secured within the ferrule 516 using an adhesive material (e.g., epoxy) and can be presented for optical coupling with optical fibers of a mating component (e.g., another fiber optic connector; not shown) when the housing 520 is inserted into an adapter, receptacle, or the like.

[0024] Although the drawings illustrate the ferrule 516 terminating twelve fibers of the multiple fiber cable 512, it should be appreciated that the ferrule 516 can be configured to terminate less than twelve fibers or more than twelve fibers of a multiple fiber cable. For example, in some aspects, the ferrule 516 may be configured to terminate twenty-four fibers of a multiple fiber cable.

[0025] The connector 500 also includes a ferrule adapter 534, a spring 536 (e.g., an oval spring), a retention body 538, and a crimp sleeve 540. As best shown in FIGS. 15 and 16, when the connector 500 is assembled, the ferrule adapter 534 is disposed at a rear end 542 (e.g., against a back surface) of the ferrule 516 to help support the optical fibers extending to the ferrule bores 528. The ferrule adapter 534 includes a pair of channels 537 that cooperate with external channels 517 of the ferrule 516 to define the pin holes 577 configured to receive the external pins (not shown).

[0026] The ferrule 516 and the ferrule adapter 534 are biased to a forward position relative to the housing 518 by the spring 536. More specifically, the spring 536 is positioned between a rear facing surface of the ferrule adapter 534 and a forward facing surface of the retention body 538. The retention body 538 includes two body halves 538a, 538b that have the same construction, including a latch member 580 and a catch 582 disposed on opposite lateral sides of the body halves 538a, 538b. Each of the body halves 538a, 538b also includes a pair of forward extending latching arms 550, and the latching arms 550 include outward extending protrusions 551 configured to engage a notch, recess, or opening 552 in a side wall of the housing 518 to couple the retention body 538 with the housing 518. Each of the body halves 538a, 538b may also include a circumferentially-extending groove 588 configured to receive a circumferential flange 541 extending radially outward from an outer surface of the crimp sleeve 540. The flange 541 may include one more flattened portions that prevent rotation of the crimp sleeve 540, and thus the cable 512 and fibers 502, relative to the retention body 538. Of course, alternative keying structures may be employed in place of the flattened portions. In some aspects, an inner support sleeve may be inserted beneath the jacket of the cable 512 to protect the fibers 502 when the crimp sleeve 540 is crimped to the cable 512.

[0027] The retention body 538 is inserted into the housing 518 when the connector 500 is assembled, and the protrusions 551 of the latching arms 550 engage openings 552 in the side wall of the housing 518. The spring 536 is compressed by this point and exerts a biasing force on the ferrule 516 via the ferrule adapter 534. The ferrule adapter 534 includes a flange configured to interact with a shoulder or stop formed within the housing 518 to retain the ferrule 516 and the ferrule adapter 534 within the housing 518. The boot 522 covers a rear portion of the retention body 538, as shown in FIGS. 14 and 15, and provides strain relief for the optical fibers 502 by limiting the extent to which the connector 500 can bend relative to the cable 512.

[0028] To insert the connector into an adapter or receptacle, the connector 500 is configured such that a user grasps the boot 522 and pushes the connector 500 into the adapter or receptacle. Pins from a mating connector (not shown) at the adapter or receptacle are received in the bores delineated by cooperative alignment of the channels 537 of the ferrule adapter 534 and the external channels 517, thereby allowing the housing to be fully inserted for proper engagement / mating with the adapter or receptacle. To disengage the connector 500 from an adapter or receptacle, the user grasps and pulls the slider 520, which may be biased by springs 556 relative to the housing 518, away from the adapter or receptacle. This way pull forces are transferred directly to the housing 518 (rather than the cable 512) to disengage the housing 518 from the adapter or receptacle.

[0029] FIG. 18 illustrates a ferrule assembly 510 configured to be pushed through a duct, for example a duct having an inner diameter less than 10mm and, in some cases, a duct having an inner diameter of 5.5mm. The ferrule assembly 510 includes the ferrule 516 terminating the plurality of fibers 502, the spring 536, and the crimp sleeve 540. As shown, the inner support sleeve 504 may be disposed beneath the jacket of the cable 512.

[0030] Referring now to FIG. 17, after the ferrule assembly 510 is pushed through a duct to a connection location of a fiber distribution system, the boot 522 can be moved over the ferrule assembly 510 and beyond the crimp sleeve 540. The ferrule adapter 534 can be positioned about the fibers 502 at the rearward end of the ferrule 516, as best shown in FIGS. 15 and 16. Then, the retention body halves 538a, 538b can be coupled together (e.g., snap-fit together) over the crimp sleeve 540 and spring 536, and the boot 522 can be moved forwardly over the rear portion of the retention body 538. The housing 518 is coupled with the retention body 538 via the cooperating protrusions 551 of the latching arms 550 and the openings 552 in the side walls of the housing 518. The shell springs 556 and shell 520 can then be coupled with the housing 518. The shell 520 may include a recessed portion 521 at a bottom inner surface and / or a top inner surface having a forward facing shoulder configured to engage a rearward facing shoulder of a projection 519 extending from a bottom outer surface and / or a top outer surface of the housing 518

Claims

1. A fiber optic connector comprising: a ferrule (316; 516); a ferrule adapter (334; 534) configured to be coupled with the ferrule; a retention body (338; 538) configured to be coupled with a multi-fiber cable; wherein the ferrule (316; 516) is configured to terminate a plurality of fibers (302; 502) of a multi-fiber cable; wherein the ferrule adapter (334; 534) and the ferrule (316; 516) cooperate to define a ferrule interface configured to mate with a ferrule of an MPO connector; wherein the ferrule (316; 516) includes external channels (317; 517) at opposing laterals sides of the ferrule; wherein the ferrule adapter includes channels (337; 537) that oppose the external channels of the ferrule; wherein the channels (337; 537) of the ferrule adapter (334; 534) and the external channels (317; 517) of the ferrule (316; 516) cooperate to define a pair of bores for receiving a pair of external pins; wherein the bores are configured to receive a pair of pins from the mating MPO connector, characterized in that the ferrule adapter (334; 534) is positioned about the fibers (302; 502) at a rear end (342; 542) of the ferrule (316; 516), wherein the ferrule adapter (334; 534) is disposed at said rear end (342; 542) against a back surface of the ferrule (316; 516).

2. The fiber optic connector of claim 1, wherein the retention body (338; 538) includes two retention body halves (338a, 338b; 538a, 538b) configured to be coupled with one another.

3. The fiber optic connector of claim 2, wherein each of the two retention body halves (338a, 338b; 538a, 538b) includes a pair of forward extending latching arms (350; 550) having outward extending protrusions (351; 553) configured to engage a notch, recess, or opening (352; 552) in a side wall of a housing (318; 518) to couple the retention body (338; 538) with the housing (318; 518).

4. The fiber optic connector of claim 2, wherein the retention body (338; 538) is configured to be coupled with the multi-fiber cable via a crimp sleeve (340; 540) configured to be crimped onto the multi-fiber cable; wherein each of the body halves (338a, 338b; 538a, 538b) includes a circumferentially-extending groove (388; 588) configured to receive a circumferential flange (341; 541) extending radially outward from an outer surface of the crimp sleeve (340; 540).

5. The fiber optic connector of claim 4, wherein the flange (341; 541) of the crimp sleeve (340; 540) includes one or more flattened portions that prevent rotation of the crimp sleeve (340; 540), and thus the cable (312; 512) and fibers (302; 502), relative to the retention body (338; 538).

6. The fiber optic connector of claim 1, further comprising: a housing (318; 518) configured to be coupled with the retention body (338; 538); a shell (320; 520) configured to be coupled with the housing (318; 518); and wherein the shell (320; 520) is configured to house a pair of springs (356; 556) bearing against a forward facing surface of the housing (318; 518) and a rearward facing surface of the shell (320; 520) to urge the shell in the forward direction.

7. The fiber optic connector of claim 6, wherein the connector is configured to be disconnected from a mating adapter by urging the shell (320; 520) in a rearward direction, thereby transferring such urging force to the housing (318; 518) rather than the cable.

8. The fiber optic connector of claim 1 or 2, further comprising a spring (336; 536) configured to urge the ferrule (316; 516) in a forward direction.

9. The fiber optic connector of claim 8, wherein the spring (336; 536) is configured to extend about fibers of the multi-fiber cable.

10. The fiber optic connector of claim 8, wherein the spring (336; 536) is configured to be compressed between a forward facing surface of the retention body (338; 538) and a rearward facing surface of the ferrule adapter (334; 534).

11. The fiber optic connector of claim 1, further comprising a pin clip (332), wherein the pin clip is configured to retain the external pins (366) that extend into the bore.