WO2006029299A2

WO2006029299A2 - Optical connector system including reduced-size mt-style ferrule

Info

Publication number: WO2006029299A2
Application number: PCT/US2005/032117
Authority: WO
Inventors: Barbara Grzegorzewska; Scot A. Ernst; Bogdan Andrei; Loreta Sadauskiene; Ilya Makhlin; Wenzong Chen; Daniel B. Szilagyi; Yuriy Belenkiy; Malcolm H. Hodge
Original assignee: Molex Incorporated
Priority date: 2004-09-10
Filing date: 2005-09-09
Publication date: 2006-03-16
Also published as: WO2006029299A3

Abstract

Optical connector systems are disclosed, each incorporating a ferrule being peripherally dimensioned to be proportionately about 50% smaller than a standard MT ferrule. The reduced-size ferrule includes a body having a multi-dimensional array of optical fiber passageways for receiving the individual optical fibers of a ribbon cable.

Description

OPTICAL CONNECTOR SYSTEM INCLUDING REDUCED-SIZE MT-STYLE

FERRULE

TECHNICAL FIELD This disclosure relates generally to optical fiber connector systems, and more particularly, to multi-fiber optical connector systems.

BACKGROUND A wide variety of fiber optic connectors have been employed to terminate optical fiber cables and to facilitate connection of the cables to other cables or other optical fiber terminal devices.

A typical fiber optic connector includes a ferrule. The ferrule holds one or more individual fibers in a precise position and ensures that when the connector is in contact with a mating connector or some other device, the fibers terminated by the connector are held in consistent alignment. A ferrule holder or other housing component of the connector secures the ferrule within the connector. Usually, the exposed fiber end(s) are inserted into the ferrule before the ferrule is inserted into the connector. A spring may be disposed within the housing or ferrule holder such that the ferrule is yieldably biased forwardly for engaging another fiber-mounting ferrule of a mated connecting device. The explosive growth in demand for capacity in communications networks has spawned an increase in the number of optical fibers within optical fiber cables, and thus, an attendant increase in the number of individual fiber connections that must be maintained in a network. As a result of the increased demands placed on optical fiber communication systems, several standard multi-fiber connectors have been developed and are commonly employed to terminate multi-fiber cables. One of the more common multi-fiber connectors is the MT RJ connector having a rectangularly-shaped MT ferrule developed by Nippon Telegraph & Telephone Corporation of Tokyo, Japan. A standard MT ferrule is capable of holding a 1x12 array of fibers.

Although currently available multi-fiber connectors are useful in many applications, a need exists for an improved optical connector that can support higher fiber counts and fiber densities (i.e., fibers per unit area). SUMMARY

To satisfy this need, the present invention provides a multi-fiber connector system having an optical connector that terminates a higher density of fibers, and yet is physically dimensioned and includes many features of a standard optical connector. To increase the fiber density, the connector itself includes a miniaturized MT-style ferrule that terminates a multi-dimensional array of fibers. By using standard connector dimensions and features, the high density connector is potentially compatible with many adapters already in the field.

In accordance with an embodiment of the invention, the mini MT-style ferrule is a one-piece monolithic part that can be manufactured from thermo-set resin material using transfer molding techniques. Other techniques can also be used to manufacture the ferrule. The ferrule's unitary construction simplifies the assembly of the optical connector itself, and the ferrule's small form factor makes the connector suitable for higher fiber count applications at a lower cost. Other aspects, features, embodiments, processes and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional features, embodiments, processes and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

It is to be understood that the drawings are solely for purpose of illustration and do not define the limits of the invention. Furthermore, the components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.

FIGS. IA-F are various detailed views of an optical ferrule in accordance with an exemplary embodiment of the present invention.

FIGS. 2A-B are perspective views of a prior art MT ferrule pin holder and boot arrangement.

FIGS. 3A-B are perspective views of an MT ferrule assembly having a unitary pin holder/boot.

FIG. 4 is a partial cross-sectional view of the MT ferrule assembly shown in FIGS. 3A-B. FIG. 5 shows perspective views of the reduced-size MT ferrule of FIGS. IA-F in a male configuration.

FIG. 6 is a perspective view of the reduced-size MT ferrule of FIGS. IA-F in a female configuration. FIG. 7 is a perspective view of an alignment sleeve for pre-aligning the male and female ferrules shown in FIGS. 5-6.

FIG. 8 is a perspective view of an alignment sleeve/ferrule assembly.

FIG. 9 is a partial cut-away perspective view of the alignment sleeve/ferrule assembly of FIG. 8. FIG. 10 is a partial cross-sectional view of an exemplary adaptor that includes the pre-alignment sleeve/ferrule assembly shown in FIGS. 8-9.

FIG. 11 is a perspective view of an example of a male MT-type ferrule having an improved means for mounting alignment pins.

FIG. 12 is a cross-sectional view of the male ferrule along section A-A of FIG. 11.

FIG. 13 is a cross-sectional view of the male ferrule along section B-B of FIG. 11.

FIGS. 14-15 are cross-sectional views of alternative exemplary configurations of the improved male MT-type ferrule. FIGS. 16A-B are exploded perspective views of the front and rear, respectively, of an exemplary LC-type connector including the ferrule illustrated in FIGS. IA-F.

FIG. 17 is a partial cut-away perspective view of the LC-type connector of FIGS. 16A-B.

FIGS. 18A-B are front perspective views of the LC-type connector of FIGS. 16A-B with various ferrule orientations.

FIG. 19 is a process diagram showing an exemplary assembly procedure for the LC-type connector of FIGS. 16A-B.

FIGS. 20-22 show various views of a dual-latch LC connector system.

FIG. 23 is a perspective view of an array optical connector system having a single center jackscrew.

FIG. 24 is a perspective view of the array optical connector system of FIG. 23 with the top of the backshell removed.

FIGS. 25-28 show various views of an array optical connector 100 having a snap- in comb. FIG. 29 is a perspective view of an exemplary MU-type connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F.

FIG. 30 is a perspective view of an exemplary double MT-RJ-type connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F. FIG. 31 is a perspective view of exemplary single and double SC-type connectors incorporating the reduced-size MT-type ferrule of FIGS. IA-F.

FIG. 32 is a perspective view of an exemplary double FC-type connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F.

FIG. 33 is a perspective view of an exemplary BLC two position type connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F.

FIG. 34 is a perspective view of an exemplary BLC four position type connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F.

FIG. 35 is a perspective view of an exemplary BLC eight position type connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F. FIG. 36 is a perspective view of an exemplary HBMT-type connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F.

FIG. 37 is a perspective view of an exemplary circular connector incorporating the reduced-size MT-type ferrule of FIGS. IA-F.

DETAILED DESCRIPTION

The following detailed description, which references to and incorporates the drawings, describes and illustrates one or more specific embodiments of the invention.

These embodiments, offered not to limit but only to exemplify and teach the invention, are shown and described in sufficient detail to enable those skilled in the art to practice the invention. Thus, where appropriate to avoid obscuring the invention, the description may omit certain information known to those of skill in the art.

FIG. IA is a perspective view of an example of a reduced-size MT-style ferrule 16 in accordance with an exemplary embodiment of the present invention. The ferrule 16 is configured to terminate a 2x6 ribbon of 125 micron diameter optical fibers and to have a form factor that is about one half that of a standard MT (mechanical transference) optical ferrule, i.e., it's exterior dimensions are about one-half that of a standard MT ferrule, as specified by IEC 60874-16.

The multi-fiber ferrule 16 can comprise multiple pieces, but is preferably a single-piece, unitary construction. In the example shown, the ferrule 16 comprises a unitary body 101 that is molded from a thermoplastic or thermoset resin material. The form factor of the ferrule 16 is that of a miniature MT ferrule, e.g., an MT-shaped ferrule that is approximately one half the size of a standard MT ferrule.

The ferrule's unitary body 101 includes a front end face 100 and a back end 102, and a plurality of fiber passageways 104 and plural alignment holes 106 extending through the body 101 between the front end face 100 and the back end 102. The alignment holes 106 are for receiving the alignment pins 20. A window 108 is formed on the top of the body 101. A back portion 103 of the body 101 has a larger cross- sectional area than the front portion of the body, creating a flange 105 that is useful for mounting the ferrule 16 in the connector housing 14. The vertical sides of the back portion 103 include protrusions 109 that are also used to properly position the ferrule 16 in a connector mount.

For illustrative purposes, the exemplary ferrule 16 terminates a single 2x6 ribbon of 125μm optical fibers. However, the ferrule 16 may be utilized to terminate any suitable number or size of multi-fiber ribbons and/or any number of optical fibers. For example, a variant of the ferrule 16 includes a 2x12 array of fiber passageways with a row spacing of 0.25mm and a passageway pitch (i.e., center-to-center spacing) of

0.125mm for terminating a 2x12 ribbon of 80μm optical fibers. The spacing and arrangement of the optical fiber terminations at the front end face 100 of the ferrule 16 may be proprietary, or alternatively, they may be in accordance with an optical fiber connector interface standard.

FIG. IB is a front plan view of the MT-type ferrule 16. The fiber passageways

104 are stacked in two rows of six 122,124, centrally aligned with the center plane 120 of the ferrule 16. The pitch of the passageways 104 is 0.25mm, and the row spacing is also 0.25mm. The two alignment holes 106 are likewise centrally aligned with the plane

120 on either side of the fiber passageways 104.

FIG. 1C is a back plan view of the MT-type ferrule 16. This view shows an interior chamber 130 of the ferrule 16, opening at the back end 102. The interior chamber 130 is for receiving the fiber ribbon. The non-terminal ends of the fiber passageways 104 open into the chamber 130.

FIG. ID is a top plan view of the multi-fiber ferrule 16. Through the window 108, plural interior guide channels 135 can be seen. Each channel 135 receives and guides an individual optical fiber of the fiber ribbon when inserted into the ferrule 16. FIG. IE is a top cross-sectional view of the MT-shaped ferrule 16 along section A-A of FIG. IB. As shown, each of the fiber passageways 104 includes a precisely formed tube for guiding a bare fiber to the front end face 100 of the ferrule 16. The diameter of each tube 140 is slightly greater (about 0.001-0.002 mm wider) than that of the fiber. The length of the tubes 140 in the upper row is about 1.8mm and the length of the tubes 140 in the lower row is about 2.1mm. The ends of the tubes 140 opening into the interior chamber 130 include flaring 142 to ease the initial alignment of the fibers with tubes 140.

FIG. IF is a side cross-sectional view of the MT-type ferrule 16 along section B- B of FIG. ID. This view shows the vertical staggering of the rows of the channels 135 and their flared ends 142. The length of each channel 135 is about 0.3mm.

FIG. 2A is an exploded perspective view of a prior art MT ferrule, pin holder and boot assembly 300. The assembly 300 includes an MT ferrule 302, a pin holder 304 having plural forward projecting alignment pins 305, and a boot 306. A fiber ribbon 308 is supported in a center passage through the boot 306 and pin holder 304.

When assembled together, as shown in FIG. 2B, the alignment pins 305 are inserted into the alignment holes 313 of the MT ferrule 302 and the terminal ends of the fiber ribbon 308 are inserted into respective fiber holes of the ferrule 302. The boot 306 is securely connected to the back of the pin holder 304. It is important that the assembly 300 provide support for the fragile fiber ribbon

308. Although the ferrule assembly 300 is useful in many applications, additional support for the fiber ribbon 308 would be advantageous, particularly in applications that use reduced-size MT ferrules, such as those disclosed herein.

FIGS. 3A-B are perspective views of an improved MT ferrule assembly 350 having a unitary pin holder/boot 352 that provides added support for the fiber ribbon 317. The unitary boot 352 is a single-piece design that essentially replaces the pin holder 304 and boot 306 of the conventional MT ferrule assembly 300. The unitary boot 352 can be made of precision molded synthetic rubber, and is preferably sized for use with the reduced-sized MT ferrule 16. The unitary boot 352 includes a front portion 355 and a back portion 357 that has a smaller cross-sectional area than the front portion 355. The front portion 355 is shaped and sized to mate with the back side of the MT-type ferrule 16 and to mount the pins 305. The ends of the alignment pins 305 can be precisely embedded in the front portion 355 of the boot 352 using insertion molding techniques to align with the alignment pin holes 106. The back portion 357 extends from the front portion 355 to provide support for the fiber ribbon 317.

As shown in the partial cross-sectional view of FIG. 4, the unitary boot 352 includes a central passageway 351 from the back of the boot 352 to its front. The passageway 351 can be sized and shaped to frictionally receive the fiber ribbon 317 so that ribbon 317 is secured in the boot 352 with the exposed optical fibers 319 properly positioned so that they can be inserted into their respective tubes. In addition or as an alternative to the friction fit, an adhesive can be used to secure the ribbon 317 in the boot 352. FIG. 5 shows perspective views of the reduced-size MT-type ferrule 16 in the male configuration. The male MT ferrule assembly 300 includes ferrule 16, an alternative pin holder 311, and alignment pins 305. In contrast to conventional pin holders, the pin holder 311 is u-shaped with an open top side. The ribbon 317 is held in the pin holder 311 by side guides formed on the interior of the side walls 327. The pin holder 311 is advantageous because it allows easier assembly of the male MT-type ferrule 16, when compared to the conventional pin holder/boot combination.

FIG. 6 shows a perspective view of the reduced-size MT-type ferrule 16 in a female configuration. The female MT ferrule assembly 309 does not have alignment pins, but instead has alignment holes 106 for receiving the alignment pins 305 of the male ferrule 300 when the two ferrules 300,309 are mated together.

FIG. 7 is a perspective view of an alignment sleeve 400 for guiding the male and female ferrules 300,309 when they are mated together. As shown in the partial cut-away view of FIG. 9, the alignment sleeve 400 pre-aligns the male ferrule pins 305 prior to their entry into the female ferrule alignment holes 106. This reduces substantially or eliminates pin stubbing. Pin stubbing is a serious problem with optical connectors because debris from a stubbed pin can interfere with light transmission through the connection by creating gaps between fiber ends, scratching fiber end faces, blocking light, etc.

Referring back to FIG. 7, the sleeve 400 includes a front end 404 and a rear end 406. An internal passageway 402 interconnects the front end 404 and the rear end 406. The sleeve 400 has an essentially rectangular cross-section with the dimensions of the interior passageway 402 precisely shaped and sized to minimize the clearance between the exterior surfaces 401 (tops, bottoms and/or sides) of the ferrules 300,309 and the passageway 402. The length of the sleeve 400 is long enough so that the inserted ferrules are precisely aligned prior to the male alignment pins entering the female alignment holes. The sleeve 400 can be made of any suitable material, and is preferably made of injection molded thermoplastic.

FIG. 8 shows a perspective view of a sleeve/ferrule assembly 430 where the alignment sleeve 400 is used to mate together male and female MT ferrules 300,309.

FIG. 10 is a partial cross-sectional view of an exemplary adapter 420 that includes the pre-alignment sleeve/ferrule assembly 430. The adapter 420 can have any suitable shape, size and/or configuration, and can include any suitable number of pre- alignment sleeves 400 and/or assemblies 430. In the example shown, the adapter 420 includes two halves 421,422 that are joined together at a mated surface 424. One or more interior walls 426 are provided to form an interior compartment for holding the pre-alignment sleeve/ferrule assembly 430. The clearance tolerances between the compartment walls 426 and the exterior surfaces of the sleeve 400 can be relaxed so that the sleeve/ferrule assembly 430 floats in the optical adapter 420. The sleeve 400 can be pre-assembled into the adapter 420, and then the ferrules

300,309 can be mated together in the pre-assembled sleeve/adapter.

FIG. 11 is a perspective view of an improved male MT ferrule 500. FIG. 12 is a cross-sectional view of the ferrule 500 along section A-A of FIG. 11, and FIG. 13 is a cross-sectional view of the ferrule 500 along section B-B of FIG. 11. The MT ferrule 500 can have any suitable form factor that is in proportion to a standard MT ferrule, and it can terminate any suitable number of fibers and fiber ribbons, and is preferably the same shape, size and configuration as the reduced-size MT ferrule 16.

The ferrule 500 eliminates the need for the pin holder found on standard MT ferrules. Any step shape of the pins 504, which snap into the slots 506 on the sides of the ferrule 500, may be used. Alternative pin configurations 530,550 having different step shapes are shown in FIGS. 14-15.

Like a conventional MT ferrule, the ferrule body 502 includes a plurality of fiber passageways 512 for receiving and terminating a fiber ribbon. However, in contrast to a conventional MT ferrule, the ferrule body 502 includes two slots 506 running the length of the ferrule sides that interconnect the exterior of the body 502 with alignment pin passages 514. A widened middle opening 556 is also formed in each ferrule side for facilitating access to the passages 514. The pins 504 can be side loaded into the passages 514 by pushing them sideways through the slots 506. The pins 504 have a back end 520, a middle section 508, and a head end 510. The back end 520 and head end 510 have larger cross sections than the middle section 508. As shown in FIG. 21, this creates pin flanges 527,531, which reduce or eliminate lateral movement of the pins 504 when they are inserted into the passages 514. The pins heads 522 can optionally include split ends 510, as shown in FIG. 11, for providing additional frictional force with mating holes of a female ferrule.

FIGS. 14-15 are cross-sectional views of alternative exemplary configurations of the male MT-type ferrule. The views illustrate alternative pin shapes 520,550. FIG. 14 shows a pin 530 with back and front ends 532,536 having smaller cross sections than a middle section 534. The pin passageway 514 of the body 502 includes an enlarged middle section 556 for receiving the larger middle section 534 of the pin 530. When placed in the passageway middle section 556, the middle section 534 limits the lengthwise movement of the pin 530.

FIG. 15 shows a second alternative pin 550 with a back end 552 having a cross section that is larger than the front end 554 of the pin 550. Essentially, the pin 550 functions in the same manner as the pin 530 of FIG. 14, but omits the narrower back end 532.

FIGS. 16A-B are exploded perspective views of the front and rear, respectively, along the central axis 15 of an exemplary LC-type connector 10 including the reduced- size MT ferrule 16 illustrated in FIGS. IA-F. The connector 10 is an example of a small form factor, multi-fiber optical connector. The optical connector 10 includes a housing specifically designed to receive the reduced-size MT-type ferrule 16. Although the multi-fiber connector and ferrule can have any suitable form factor and can terminate any suitable number of fibers having any desired characteristics, the connector preferably has a standard LC footprint, and the ferrule is preferably the MT-type ferrule 16.

The connector 10 includes an elongated ferrule housing 14, the ferrule 16, an alignment pin holder 18 having at least a pair of alignment pins 305, a compression spring 22, an elongated extender cap 24, a crimp tube 26 and a boot 28. As illustrated, the assembled multi-fiber connector 10 may be axially inserted into an adapter 12 in order to couple the connector 10 to a passive or active device or connector.

The elongated housing 14 includes a front end 21 and a rear end 23. An internal passageway 25 interconnects the front end 21 and the rear end 23. The housing further comprises a pair of opposed lateral sides 29, each lateral side 29 having a window 31. The housing 14 has an essentially square cross-section with the dimensions of a LC connector, that is, approximately 5 mm from side to side. The general style of the housing 14 is that of the well known RJ45 housing which contributes to the ease and familiarity of use of the connector 10. An integrally formed spring latch 35 extends outwardly from the top side of the housing 14 for cooperating with a corresponding spring latch 39 extending from the top of the extender cap 24. The spring latches 35,39 cooperate together to release the housing 14 from the adapter 12, after being inserted. The spring latches 35,39 are well known devices that can be constructed in a number of different ways. The spring latches 35,39 are preferably formed so that they can be deformed somewhat by the application of force, but then return to their original shapes after the force is removed.

A slot 27 opening at the front of the housing 14 is provided inside of the housing 14 for receiving and retaining the multi-fiber ferrule 16. The slot 27 is formed within the housing having a size and shape so as to limit lateral and forward axial movement (toward the connector 12) of the emplaced multi-fiber ferrule 16. When the multi-fiber ferrule 16 is placed within the housing 14, the ferrule 16 protrudes beyond the front 21 of the housing 14.

Once the multi-fiber ferrule 16 has been received in the housing 14, it is desirable that the ferrule 16 has a nominal amount of backward axial movement. Accordingly, when not coupled to another optical device or connector, the multi-fiber ferrule 16 is axially loaded so that it protrudes from the housing 14 (as shown in FIG. 17) by a loading mechanism, such as the compression spring 22.

The extender cap 24 includes a front substantially rectilinear portion 37 that is sized and configured to be received in a correspondingly sized and configured passageway 25 at the rear end 23 of the housing 14. In particular, the portion 37 securely slides within the passageway 25 and is held in place by stops 33, which engage corresponding windows 31 in the sides 29 of the housing 14. A flange 41, having a larger cross-section than the portion 37, abuts the rear end 23 of the housing 14 when the extender cap 24 is inserted into the housing 14. A tubular neck 43 extends axially along axis 15 and operates as a guide for the multi-fiber ribbon 52 (shown in FIG. 17) terminated by the multi-fiber ferrule 16 and extending through a cylindrical passageway 45 defined by the extender cap 24. The portion of the cylindrical passageway 45 defined by the rectilinear portion 37 is sized and shaped to receive and hold the compression spring 22. The spring 22 provides axial loading of the multi-fiber ferrule 16 for maintaining positive pressure during an optical connection.

During assembly, sheathing from the optical cable 50 is placed around the tubular neck 43 of the extender cap 24. The crimp tube 26 is then placed over the optical cable sheathing and tubular neck 43, and compressed using, for instance, a conventional manual crimping tool, to securely the fasten the cable to the extender cap 24.

The adapter 12 is a generally elongated structure of a unitary construction having a front end 13, a rear end 17, and an internal passage 11 that extends from the front end 13 to the rear 17. At the front end 13 of adapter 12, the passageway 11 is defined in a shape for receiving connector 10. In particular, the passageway 11 is sized to correspond to the dimensions of the housing 14 so as to receive and precisely guide the axial movement of the connector 10 within the adapter 12. In addition, an internal notch (not shown) receives and operates in conjunction with the spring latch 35 to selectively hold the connector 10 within the adapter 12.

At the rear end 17 of the adapter 12 is a slot 19 which is sized and shaped to receive the protruding front end portion of the multi-fiber ferrule 16.

The adapter 12 may be connected to (i.e., interfaced with) a passive connection device (e.g., another adapter receiving a second mating optical fiber connector) or an active system (e.g., an optical transceiver or surface emitting laser).

The alignment pin holder 18 may be included for a male ferrule, as shown, and excluded for a female ferrule. As discussed below, the multi-fiber ferrule 16 includes alignment holes for receiving the alignment pins 305 of the pin holder 18. The rear end of the pin holder 18 is adapted to receive the compressing spring 22.

The adapter 12, housing 14 and boot 28 are each preferably of unitary construction, composed of a resilient thermoplastic, so as to be light weight and durable. These parts may be fabricated using any number of suitable methods, but they are preferably molded using well-known injection molding techniques. The front part of the extender cap 24 is preferably made from molded thermoplastic, with the tubular neck 43 being a metal insert frictionally fitted to the front plastic part.

FIG. 17 is a partial cut-away perspective view of the connector 10 frilly assembled. This view shows the attachment of the optical cable 50 to the connector 10 and passage of the cable's multi-fiber ribbon 52 through the connector 10.

FIGS. 18A-B show perspective views of the connector of FIGS. 16A-B with various ferrule orientations. In particular, FIG. 18A shows the connector 10 having a horizontally oriented ferrule 16, whereas FIG. 18B shows a connector 61 having a vertically oriented ferrule 16. In FIG. 18B, the connector housing 60 has a structure similar to that of the housing 14 shown in FIGS. 16A-B, with the exception that the housing slot 27 for receiving the ferrule 16 is vertically aligned, rather than horizontally aligned as in FIGS. 16A-B. FIG. 19 is a process diagram showing an exemplary assembly procedure for the connector shown in FIGS. 16A-B. In step 1, the boot 28, crimp tube 26, extender cap 24 and spring 22 are slid onto the optical cable 50. The ribbon fiber 52 is terminated with the ferrule 16.

In step 2, the alignment pin holder 18 is assembled with the ferrule 16 by inserting the pins 305 into the alignment holes 106 of the ferrule 16.

This step is performed only for male ferrule terminations, and not for female ferrule terminations.

In step 3, the compression spring 22 is mounted to the back of the pin holder 18.

In step 4, the housing 14 is slid over the ferrule 16, pin holder 18 and spring 22 assembly from the front.

In step 5, the extender cap 24 is snapped into the housing 14 and the cable sheathing, preferably made of Kevlar, is slid over the tubular neck 43 of the extender cap 24. In step 6, the crimp tube 26 is placed over the sheathing surrounding the tubular neck 43 and crimped to secure the sheathing to the extender cap 24. In step 7, the boot 28 is slid over the crimp tube 26 to abut against the front portion of the extender cap 24. The boot 28 is held in place by friction and/or a suitable adhesive.

FIG. 20 is a perspective view of a dual-latch LC connector 200. The LC connector 200 has two or more opposing latches 202 on opposite sides of the connector body. The dual-latch design is a significant improvement over the single-latch design of a conventional LC connector. The conventional single-latch configuration creates non¬ uniform axial forces when the connector is attached to an LC adapter, which can cause connector insertion loss.

As with a conventional LC connector, the dual-latch connector 200 receives an optical cable 50 and terminates one or more optical fibers at a ferrule 16. The dual-latch connector 200 can be configured to carry any suitable number of optical fibers and/or fiber ribbons and any type of optical ferrule(s), including the reduced-size MT-type ferrule 16. FIG. 21 is a perspective view of an adapter 206 for receiving two dual-latch LC connectors at either of its ends 207. The rectilinear-shaped adapter 206 has a generally rectilinear.interior passageway connecting the ends 207. The passageway is shaped and sized to receive two opposing dual-latch LC connectors 200, as shown in FIG. 22. The adapter 206 includes four windows 208 to lock the LC connectors 200 in place when inserted into the adapter 206. The windows 208 are paired together on opposite sides of the adapter 206. The hooked ends 203 of the latches 202 engage a pair of the windows 208 when the LC connectors 200 are inserted into the ends 207 of the adapter 206. The adapter 206 can be fabricated as a single piece from any suitable material, and is preferably made using a molded thermoplastic.

FIG. 22 is a perspective view showing two of the dual-latch LC connectors 200 inserted into the adapter 206. The adapter 206 is mounted on a support 211, such as a panel. The support 211 includes a through hole or other suitable means for receiving and securing the adapter 206.

FIG. 23 is a perspective view of an exemplary connector system 611 including an adapter 632 and corresponding array connector 610 having a single center jackscrew 616. The array connector 610 carries one or more fiber optic ferrules, each of which terminates one or more optical fibers carried in the optical cable 620. The single center jackscrew 616 design is advantageous over conventional double jackscrew designs because it reduces the lateral profile of the connector 610 and also serves to prevent binding caused by unequal tightening of two jackscrews.

As illustrated, the connector 610 may be axially inserted into an adapter 632 in order to couple the connector 610 to a passive or active device or connector. The adapter 632 includes a threaded center hole 630 for receiving a threaded end 633 of the center jackscrew 616.

The connector 610 includes a backshell 625 fastened to a connector body 618. The backshell 625 includes a top portion 628 mated to a bottom portion 612 to form an enclosed space therebetween. When mated together, the top and bottom . portions 628,612 form an opening 614 around a thumbscrew 624 of the center jackscrew 616. Through the opening 614, the thumbscrew 624 can be rotated by a user to rotate the threaded end 633 of the jackscrew 616 in the center hole of the adapter 632, whereby selectively tightening or loosening the connector 610 to or from the adapter 632. The connector body 618 includes one or more alignment pins 634 that are received by one or more alignment holes 637 of the adapter 632 when the connector 610 and adapter 632 are mated together.

FIG. 24 shows a perspective view of a mini-array connector 610 with the top portion 628 removed, exposing the enclosed space of the backshell 625 and the fiber ribbons 622 of the cable 620 passing through the space. Also visible is the shaft 626 of the center jackscrew 616, walls 623 forming the backshell opening 614, and a ferrule comb 641 inserted in the connector body 618.

The walls 623 protrude upwardly from the interior bottom floor of the bottom portion 612. In addition to forming the opening 614 around the thumbscrew 624, the two side walls form channels 621 between the exterior side walls 643 of the backshell 625 that allow the fiber ribbons 622 to pass around the thumbscrew opening 614.

The adapter 632 and connector parts 618,625,641 can be made of any suitable material(s), such as a resilient thermoplastic. These parts may be fabricated using any number of suitable methods, and they are preferably machined or die cast. The center jackscrew 616 can be made from any suitable material, including metal" and/or thermoplastic.

The adapter 632, connector 610, and ferrules used thereby can have any suitable form factor and can carry any suitable number of fiber ribbons or fibers having any desired characteristics. The adapter 632 and connector 610 can be designed to carry any type of optical ferrule, including the reduced-size MT-type ferrule 16.

FIGS. 25-26 are perspective views of an array optical connector 700 having a single snap-in comb 701. Instead of two-comb assembly that typically is found in known array connectors, the connector 700 uses the snap-in comb 701. The comb 701 can be molded thermoplastic, and it is shaped and sized to be integrally inserted into a corresponding compartment formed in the connector body 704.

As shown in FIGS. 25-26, the comb 701 can include a center hole 711 for receiving the shaft of a center jackscrew 706. The comb 701 can include any suitable number of gaps 707 for receive fiber ribbons and ferrules. The gaps 707 can also have any suitable size and shape.

FIG. 25 shows the lower portion 722 of the backshell 702 of the connector 700 detached from the connector body 704. The upper portion of the backshell 702 is not shown in FIGS. 3-4 for the sake of simplicity. The front of the backshell 702 includes an extended lower ledge 708 and side end faces 709 for abutting against and connecting to the connector body 704 when the connector body 704 and the backshell 702 are assembled together, as shown in FIG. 26. When connected together, the side end faces 709 of the backshell 702 overlap end portions 710 of the comb 701 to further secure the comb 701 in place within the connector body 704. FIG. 27 is a cross-sectional view of the connector 700 along the A-A section line of FIG. 26. FIG. 27 shows the lower portion 722 of the backshell 702 mated to the connector body 704. Also shown are the optical cable 620, cable boot 740, plural cable ribbons 22 and ferrules 742.

FIG. 27A is a detailed cross-sectional view of a snap-in retaining component 724 that can be included on the exterior surface of the comb 701. In the example shown, the retaining component 724 is a wedge-shaped ridge extending slightly away from the exterior sides of the comb 701. When the comb 701 is inserted into the connector body 704, the ridge mates with a corresponding wedge-shaped trench 723 formed in the interior sidewalls of the connector body 704 to securely fasten the comb 701 in place within the connector body 704. Other shapes, lengths and configurations of the retaining component 724 and trench 723 can be used to secure the comb 701 within the connector body 704. Alternatively, the retaining component 724 and trench 723 can be omitted and the comb 701 can be sized and shaped to frictionally fit against the interior walls of the connector body 704 without the use of the retaining component 724. FIG. 28 is an exploded view of the connector 700 previously illustrated in FIGS.

25-27. As shown, the upper portion 725 and lower portion 722 of the backshell 702 both include front extending ledges 731,708. The extending ledges 731,708 include protruding ridges 737,735. When the upper and lower portions 725,722 and the connector body 704 are assembled together, the protruding ridges 737,735 engage respective trenches 733 formed on the top and bottom sides of the connector body 704 to secure the backshell 702 to the connector body 704. One or more fasteners 726 secure together the upper and lower portions 725,722 of the backshell 702.

FIG. 29 is a perspective view of an exemplary MU-type connector 800 incorporating the reduced-size MT-type ferrule 16. The MU-type connector 800 includes a body 802 having exterior dimensions, cross-sections, and design features generally compatible with industry standards for MU connectors. However, the body 802 is also specifically designed to accept the MT-type ferrule 16. A semi-flexible boot 804 extends from the back end of the body 802 for securing an optical cable 806. The optical cable 806 passes through the boot 804 and body 802, and it is terminated by the ferrule 16.

FIG. 30 is a perspective view of an exemplary double MT-RJ-type connector 820 incorporating a pair of the reduced-size MT-type ferrules 16. The MT-RJ-type connector 820 includes a body 822 having exterior dimensions, cross-sections, and design features generally compatible with industry standards for MT-RJ connectors. However, the body 822 is also specifically designed to accept the two MT-type ferrules 16 in a stacked arrangement. A semi-flexible boot 824 extends from the back end of the body 822 for securing an optical cable 826. The optical cable 826 passes through the boot 824 and body 822, and it is terminated by the ferrules 16. FIG. 31 is a perspective view of an exemplary single SC-type connector 842 and a double SC-type connector 845. Both of the connectors 842,845 incorporate the reduced-size MT-type ferrule 16. The SC-type connectors 842,845 each include a body 844 having exterior dimensions, cross-sections, and design features generally compatible with industry standards for SC connectors. However, the body 822 is also specifically designed to accept either one or two of the MT-type ferrules 16. With the double SC- type connector 845, the ferrules 16 are vertically oriented in a side-by-side arrangement.

A semi-flexible boot 846 extends from the back end of the body 822 for securing an optical cable 848. The optical cable 848 passes through the boot 846 and body 844, and it is terminated by the ferrules 16. FIG. 32 is a perspective view of an exemplary double FC-type connector 860 incorporating a pair of the reduced-size MT-type ferrules 16. The FC-type connector 860 includes a body 862 having exterior dimensions, cross-sections, and design features generally compatible with industry standards for FC connectors. However, the body 862 is also specifically designed to accept and house the two MT-type ferrules 16 in a stacked arrangement. A semi-flexible boot 864 extends from the back end of the body 862 for securing an optical cable 866. The optical cable 866 passes through the boot 864 and body 862, and it is terminated by the ferrules 16.

FIG. 33 is a perspective view of an exemplary BLC two position type connector incorporating a pair of the reduced-size MT-type ferrules 16. The BLC two position type connector 880 includes a body 882 having exterior dimensions, cross-sections, and design features generally compatible with industry standards for BLC two position connectors. As with conventional BLC connectors, the body 882 includes two resilient, horizontally-opposed arms 883 for detachably coupling to a corresponding BLC two position adapter (not shown). Attachment means 885, such as a threaded fastener, allows the body 882 to be fastened to a mounting surface 884, such as a panel or printed circuit board.

The body 882 is also specifically designed to accept and house the two MT-type ferrules 16. The back end of the body 882 includes conventional means for securing two optical cables 886 to the body 882. The optical cables 886 pass through body 882, and each cable 886 is terminated by a respective ferrule 16.

FIG. 34 is a perspective view of an exemplary BLC four position type connector 890 incorporating four of the reduced-size MT-type ferrules 16. The BLC four position type connector 890 includes a body 892 having exterior dimensions, cross-sections, and design features generally compatible with industry standards for BLC four position connectors. As with conventional BLC connectors, the body 882 includes two resilient, horizontally-opposed arms 883 for detachably coupling to a corresponding BLC four position adapter (not shown). Attachment means 885, such as a threaded fastener, allows the body 892 to be fastened to a mounting surface 884, such as a panel or printed circuit board.

The body 892 is also specifically designed to accept and house the four MT-type ferrules 16. The back end of the body 892 includes conventional means for securing four optical cables 886 to the body 892. The optical cables 886 pass through body 892, and each cable 886 is terminated by a respective ferrule 16. FIG. 35 is a perspective view of an exemplary BLC eight position type connector

896 incorporating eight of the reduced-size MT-type ferrules 16. The BLC eight position type connector 896 includes a body 898 having exterior dimensions, cross- sections, and design features generally compatible with industry standards for BLC eight position connectors. As with conventional BLC connectors, the body 898 includes two resilient, horizontally-opposed arms 883 for detachably coupling to a corresponding BLC eight position adapter (not shown). Attachment means 885, such as a threaded fastener, allows the body 898 to be fastened to a mounting surface 884, such as a panel or printed circuit board.

The body 898 is also specifically designed to accept and house the eight MT-type ferrules 16. The back end of the body 898 includes conventional means for securing eight optical cables 886 to the body 898. The optical cables 886 pass through body 898, and each cable 886 is terminated by a respective ferrule 16.

FIG. 36 is a perspective view of an exemplary HBMT-type connector 920 incorporating four reduced-size MT-type ferrules 16. The HBMT-type connector 920 includes a body 922 having exterior dimensions, cross-sections, and design features generally compatible with industry standards for HBMT connectors. As with conventional HBMT connectors, the body 922 includes four mounting lugs 930 having threaded holes formed therein for receiving mounting screws. The mounting lugs 930 are arranged in pairs perpendicular to each other so that the body 922 can be fastened to perpendicular mounting surfaces 926,928, such as panels or printed circuit boards, as is shown in the example.

The body 922 is also specifically designed to accept and house the four MT-type ferrules 16. The back end 923 of the body 922 includes conventional means for securing four optical cables 924 to the body 922. The optical cables 924 pass through body 922, and each cable 924 is terminated by a respective ferrule 16.

FIG. 37 is a perspective view of an exemplary circular push-pull optical connector 940 incorporating the reduced-size MT-type ferrule 16. The circular connector 940 includes a generally cylindrical body 941 having cylindrical extension 942 and annular stop 945 extending radially from the back end of the cylindrical extension 942. The annular stop 945 provides a mating surface 949 for engaging a corresponding mating surface of an adapter when the connector 940 is inserted therein.

The cylindrical extension 942 is dimensioned in length and diameter to be precisely received in an adapter so as to minimize insertion loss. An alignment notch 943 is formed in the exterior surface of the extension 942 near the open front end 947. The alignment notch corresponds to an alignment lug formed within the adapter passageway to facilitate proper alignment of the mated connector 940 and adapter.

The body 941 is specifically designed to accept and securely house the MT-type ferrule 16. A semi-flexible boot 944 extends from the back end of the body 941 for securing an optical cable 946. The optical cable 946 passes through the boot 944 and body 941, and it is terminated by the ferrule 16.

Use of the reduced-size MT-type ferrule 16 is not limited to the connector designs disclosed herein. The reduced-size MT-type ferrule 16 can be incorporated in other connector designs or configurations such as MTP, MPO or the like.

While one or more specific embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments are possible that are within the scope of this invention. Further, the foregoing detailed description and drawings are considered as illustrative only of the principles of the invention. Since other modifications and changes may be or become apparent to those skilled in the art, the invention is not limited the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents are deemed to fall within the scope of the invention.

Claims

CLAIMSWhat is claimed is:

1. A ferrule, comprising: a rectangular body having a front end face and a back end, the rectangular body being peripherally dimensioned to be proportionately about 50% smaller than an MT standard ferrule; and a two-dimensional array of optical fiber passageways extending through the body between the front end face and the back end, each of the passageways having a cross- sectional area sized to snugly receive an individual optical fiber inserted therein.

2. The ferrule of claim 1, wherein the body includes a plurality of alignment pin holes extending into the body from the front end face, the alignment pin holes having a diameter that is about 50% smaller than an MT standard ferrule alignment hole.

3. The ferrule of claim 1 , wherein the passageways in each row of the array have a predetermined length that is not the same as the predetermined lengths of passageways in other rows.

4. The ferrule of claim 1, wherein the passageways open into an interior chamber of the body.

5. The ferrule of claim 4, further comprising stepped guide channels formed in the interior chamber, each guide channel corresponding to a respective passageway.

6. The ferrule of claim 5, wherein the guide channels are wider than the passageways.

7. The ferrule of claim 1, wherein the rectangular body is of one-piece construction.

8. The ferrule of claim 1, wherein the ferrule is included in an optical connector selected from the group consisting of a simplex LC type connector, a duplex LC type connector, an MU type connector, a duplex MT RJ type connector, a simplex FC type connector, a duplex FC type connector, an SC type connector, a BLC two- position type connector, a BLC four-position type connector, a BLC eight-position type connector, and an HB-MT type connector.

9. The ferrule of claim 1, further comprising a pin holder including: a single-piece boot having a hole formed therein sized to accept a fiber optic cable; and a plurality of alignment pins, each pin having an end embedded in the boot so that the pin aligns with a respective alignment hole of the body.

10. The ferrule of claim 1, wherein the body includes: an alignment pin hole running lengthwise along the side of the body, the alignment pin hole having a predetermined diameter sufficient to receive at least a section of an alignment pin; a slot formed in the side of the body connecting the pin alignment hole to the exterior of the body; and an alignment pin having a narrow section and at least one wide section, the narrow section having a diameter sized to be inserted through the slot into the alignment pin hole and at least one wide section having a diameter greater than the alignment pin hole so as to limit lengthwise movement of the alignment pin inserted therein.

11. The ferrule of claim 10, wherein at least one wide section includes two wide sections at either end of the alignment pin.

12. The ferrule of claim 10, wherein at least one wide section includes a split end having a plurality of resilient members that can be flexed toward the lengthwise axis of the pin.

13. An optical connector system, comprising: an alignment sleeve having a rectangular passageway connecting rectangular first and second openings of the sleeve, the passageway having predetermined dimensions sized and shaped to align the alignment pins of a male MT-type ferrule inserted into the passageway through the first opening with the alignment pin holes of a female MT-type ferrule inserted into the passageway through the second opening.

14. The optical connector system of claim 13, wherein the predetermined dimensions minimize the clearance between the exterior surfaces of the ferrules and the surfaces of the passageway.

15. The optical connector system of claim 13 , further comprising: the male MT-type ferrule having a plurality of alignment pins extending therefrom; and the female MT-type ferrule having a plurality of alignment pin holes formed therein, each of the alignment pin holes having a cross section sized to snugly accept one of the alignment pins.

16. The optical connector system of claim 13, wherein each of the MT-type ferrules has a two-dimensional array of optical fiber passageways extending between a front end face and a back end of a body, each of the passageways having a cross section sized to snugly receive an individual optical fiber inserted therein.

17. The optical connector system of claim 13, wherein the rectangular body of each of the ferrules is peripherally dimensioned to be proportionately about 50% smaller than an MT standard ferrule.

18. An optical connector, comprising: a ferrule comb having an array of gaps sized and shaped to receive an array of fiber optic ferrules, each ferrule adapted to terminate one or more optical fibers; and a single jackscrew centered in the ferrule comb.

19. The optical connector of claim 18, wherein the jackscrew includes a thumb screw allowing a user to rotate the jackscrew.

20. The optical connector of claim 18, wherein the jackscrew includes a threaded end.

21. The optical connector of claim 18, further comprising a connector body having a passageway therethrough sized and shaped to frictionally receive the ferrule comb.

22. The optical connector of claim 21, further comprising one or more alignment pins extending from the front side of the connector body.

23. The optical connector of claim 21, further comprising a backshell extending from the back side of the connector body.

24. The optical connector of claim 23, wherein the backshell includes side walls having widened front ends for abutting against the connector body and overlapping a portion of the passageway.

25. The optical connector of claim 23, wherein the backshell forms an enclosure extending from the back side of the connector body.

26. The optical connector of claim 23, wherein the backshell includes a thumbscrew opening.

27. The optical connector of claim 18, wherein the ferrule comb includes a snap-in retaining component for securely fastening the ferrule comb within a connector body.

28. The optical connector of claim 18, wherein the ferrule comb gaps are sized and shaped to accept an MT-type ferrule.

29. The optical connector of claim 28, wherein the ferrule comb gaps are sized and shaped to accept MT-type ferrules that are peripherally dimensioned to be proportionately about 50% smaller than an MT standard ferrule.