This disclosure relates generally to optical fibers, and more particularly to ferrules for multi-fiber optical connectors, along with optical connectors and cable assemblies including such ferrules, and methods relating to these components.
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 “field-installable” connectors).
Many different types of optical connectors exist. In environments that require high density interconnects and/or high bandwidth, such as datacenters, 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 is standardized according to TIA-604-5 and IEC 61754-7. 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.
Despite the widespread use of MPO connectors in datacenter environments, there are still challenges/issues to address. For example, insertion of optical fibers into MPO connectors can be challenging. Ferrules for MPO connectors can have features that either (1) stop optical fibers, upon insertion into the ferrule, thereby not allowing the optical fibers to advance through the ferrule microholes, or (2) allow the optical fibers, upon insertion into the ferrule, to cross over into adjacent ferrule microholes such that one optical fiber does not correspond to each ferrule microhole.
Additionally, securing the optical fibers in the ferrule of an MPO connector can be a challenge. An adhesive material is typically used for this purpose, with adhesive material being injected or otherwise supplied into an internal cavity of the ferrule. There must be sufficient adhesive material to ensure that the optical fibers are sufficiently bonded/secured to the ferrule. To avoid uncertainty on whether a sufficient amount of adhesive material is supplied, there may be a tendency to completely fill the internal cavity of the ferrule. Doing so, however, may increase the likelihood of the adhesive material being disposed on an exterior of the ferrule or otherwise exiting the ferrule, both of which may interfere with the normal operation of the ferrule as part of an optical connector.
New multifiber ferrule and connectors designs have been proposed, such as smaller multifiber ferrules and very small form factor connectors including such ferrules. However, fiber insertion and adhesion challenges remain with the structural features of these new ferrule designs.
Improvements in the foregoing are desired.
The present disclosure relates to a multi-fiber ferrule having a plurality of bores where each bore has an adjacent divider that separates the bores. The divider also facilitates insertion of an optical fiber into each bore.
In one embodiment, a ferrule for an optical connector configured to accept a plurality of optical fibers. The ferrule comprising: a body having a front end and a back end, the body extending in a longitudinal direction between the front end and the back end; a plurality of bores extending into the body from the front end toward the back end, wherein each bore is configured to receive one of the plurality of optical fibers; a plurality of tapered dividers wherein each tapered divider has: a first end adjacent to a respective bore of the plurality of bores and a second end proximal to the back end of the ferrule; a cross-sectional shape at the first end that spans a circumference of the respective bore such that each of the plurality of bores are separated from each other; and tapered surfaces from the second end to the first end.
In another embodiment, the back end of the ferrule includes an indicia whereby the indicia provides a visual indicator of horizontal alignment of the plurality of optical fibers within the plurality of bores of the ferrule. In another embodiment, the indicia extends from the back end of the ferrule to the second end of the tapered divider. In another embodiment, the tapered divider has a height H1 at a first end and a height H2 at the second end, wherein a height ratio H2:H1 ranges between 1.2:1 and 3:1. In another embodiment, the tapered divider has a width W1 at a first end and a width W2 at the second end, wherein a width ratio W2:W1 ranges between 1.2:1 and 3:1. In another embodiment, the tapered divider has a circular cross section at the first end and a square cross section at the second end. In another embodiment, the tapered surface of the tapered divider has an angle ranging between 15° and 45° relative to a longitudinal axis of one of the bores. In another embodiment, adjacent tapered dividers have corresponding adjacent tapered surfaces that form an edge, wherein the edge is configured to prevent an optical fiber from being inserted into a non-corresponding bore. In another embodiment, the second end of the tapered divider is flush with the back end of the ferrule. In another embodiment, the plurality of bores comprises a first row of bores and a second row of bores spaced from the first row of bores, wherein the first row of bores are coplanar with each other and the second row of bores are coplanar with each other. In another embodiment, the first row of bores and the second row of bores are separated by a spacer that is flush with the back end of the ferrule, and wherein the spacer is integrally formed with the ferrule. In another embodiment, the ferrule further comprises a window formed on a top surface or a bottom surface of the ferrule, wherein the window extends into a lead-in section of the ferrule adjacent to the tapered divider.
In another embodiment, optical connector, comprising: a ferrule according to any of the embodiments; and a plurality of optical fibers secured to the ferrule, wherein each optical fiber extends from the back end of the body and into one of the microholes. In another embodiment, the plurality of bores comprises a first row of bores and a second row of bores spaced from the first row of bores, wherein the first row of bores are coplanar with each other and the second row of bores are coplanar with each other. In another embodiment, the plurality of optical fibers comprises a first ribbon of optical fibers and a second ribbon of optical fibers, wherein the first ribbon of optical fibers and the second ribbon of optical fibers are coplanar with each other; and wherein the first ribbon of optical fibers and the second ribbon of optical fibers are separated by an optical fiber spacer; wherein the first ribbon of optical fibers, the second ribbon of optical fibers, and the optical fiber spacer are inserted into the back end of the ferrule such that the first ribbon of optical fibers are inserted into the first row of bores and the second ribbon of optical fibers are inserted into the second row of bores. In another embodiment, the first row of bores and the second row of bores are separated by a spacer that is flush with the back end of the ferrule, and wherein the spacer is integrally formed with the ferrule. In another embodiment, the plurality of optical fibers comprises a first ribbon of optical fibers and a second ribbon of optical fibers, wherein the first ribbon of optical fibers and the second ribbon of optical fibers are coplanar with each other; and wherein the first ribbon of optical fibers and the second ribbon of optical fibers are inserted into the back end of the ferrule such that the first ribbon of optical fibers are inserted into the first row of bores and the second ribbon of optical fibers are inserted into the second row of bores.
In another embodiment, a method of terminating a plurality of optical fibers with the ferrule of any of the embodiments, comprising: aligning the optical fibers with the bores of the ferrule; and extending the optical fibers through the back end of the ferrule and into the bores, wherein the tapered divider provides that one optical fiber extends through each of the bores. In another embodiment, the aligning step comprises: aligning a first ribbon of optical fibers with a first row of bores; and aligning a second ribbon of optical fibers with a second row of bores. In another embodiment, the aligning the first ribbon of optical fibers includes aligning an optical fiber of the first ribbon with an indicia on a back end of the ferrule; and wherein the aligning the second ribbon of optical fibers includes aligning an optical fiber of the second ribbon with the indicia on the back end of the ferrule. In another embodiment, the first ribbon of optical fibers and the second ribbon of optical fibers are separated by an optical fiber spacer that is inserted into the ferrule with the first ribbon of optical fibers and the second ribbon of optical fibers. In another embodiment, the method, further comprising: supplying an adhesive into the tapered divider. In another embodiment, the adhesive is supplied to the bores through a window formed in a top surface of the ferrule and extending into a lead in section of the ferrule adjacent to the tapered divider.
Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the technical field of optical communications. It is to be understood that the foregoing general description, the following detailed description, and the accompanying drawings are merely exemplary and intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments. Features and attributes associated with any of the embodiments shown or described may be applied to other embodiments shown, described, or appreciated based on this disclosure.
Various embodiments will be further clarified by examples in the description below. In general, the description relates to multi-fiber ferrules and fiber optic connectors and cable assemblies incorporating such multi-fiber ferrules. In particular, the present disclosure relates to a multi-fiber ferrule having a plurality of bores where each bore has an adjacent divider that separates the bores. The divider also facilitates insertion of an optical fiber into each bore.
The fiber optic connectors may be based on known connector designs, such as MPO connectors. To this end,
As shown in
As shown in
Both the ferrule 16 and guide pin assembly 34 are biased to a forward position relative to the housing 18 by the spring 36. More specifically, the spring 36 is positioned between the pin keeper 46 and a portion of the crimp body 38. The crimp body 38 is inserted into the housing 18 when the connector 10 is assembled and includes latching arms 50 that engage recesses 52 in the housing. The spring 36 is compressed by this point and exerts a biasing force on the ferrule 16 via the pin keeper 46. The rear portion 42 of the ferrule defines a flange that interacts with a shoulder or stop formed within the housing 18 to retain the rear portion 42 within the housing 18.
In a manner not shown in the figures, aramid yarn or other strength members from the cable 12 are positioned over an end portion 54 of the crimp body 38 that projects rearwardly from the housing 18. The aramid yarn is secured to the end portion 54 by the crimp ring 40, which is slid over the end portion 54 and deformed after positioning the aramid yarn. The boot 22 covers this region, as shown in
Now that a general overview of the connector 10 has been provided, ferrule designs will be described. To this end,
Ferrule 16 includes a ferrule body 17 extending in a longitudinal direction (i.e., along a longitudinal axis L) between front and back ends 19, 21 of the ferrule body 17. The front end 19 of the ferrule body 17 defines an end face 23 where microholes 25 are included.
As shown in
Ferrule 16 also includes pin holes 31, 33 that are configured to receive guide pins when mounting ferrule 16 within a connector 10. In
Referring now to
Referring now to
When optical fibers 67 or optical fiber ribbons 59, 61 are inserted into aperture 47, the optical fiber(s) engage with tapered divider 49 prior to entering bore 37. With reference to
As shown, tapered divider 49 comprises a first end 43 adjacent to bore 37 and a second end 53 proximal to back end 21 with tapered surfaces 55 spanning from first end 43 to second end 53. At first end 43, tapered divider 49 has a cross sectional shape that is coaxial with longitudinal axis L1 of bore 37. Stated another way, the cross section of tapered divider 49 at first end 43 spans the circumference of bore 37 and is coaxial with bore 37. In some embodiments, the cross-section shape of tapered divider 49 at first end 43 is circular where the cross section is coaxial with bore 37. However, it is within the scope of the present disclosure that in alternate embodiments, alternate suitable cross section shapes may be used. In some embodiments, tapered divider 49 has a length L2 that is less than 250 microns.
As shown, at first end 43, tapered divider 49 has a height H1 ranging between 100 microns and 250 microns, between 100 microns and 150 microns, or between 125 microns and 150 microns. Tapered divider 49 also has a width W1 ranging between 100 microns and 250 microns, between 100 microns and 150 microns, or between 100 microns and 125 microns at first end 43. In some embodiments, first end 43 of tapered divider 49 is adjacent to bore 37 of ferrule 16.
At second end 53, tapered divider 49 has a cross sectional shape that is coaxial with longitudinal axis L1 of bore 37. Stated another way, the cross section of tapered divider 49 at second end 53 spans the circumference of bore 37 and is coaxial with bore 37. In some embodiments, the cross-section shape of tapered divider 49 at second end 53 is square where the cross section is coaxial with bore 37. However, it is within the scope of the present disclosure that in alternate embodiments, alternate suitable cross section shapes may be used. As shown, at second end 53, tapered divider 49 has a height H2 ranging between 200 microns and 800 microns, between 200 microns and 500 microns, or between 200 microns and 250 microns. Tapered divider 49 also has a width W2 ranging between 150 microns and 350 microns at second end 53. In some embodiments, width W2 of tapered divider 49 is equal to the pitch between bores 37. As used herein, “pitch” refers to the distance from a center of one bore 37 to a center of another adjacent bore 37. In some embodiments, second end 53 of tapered divider 49 is within lead in section 35. In some embodiments, second end 53 of tapered divider 49 is flush with back end 21 of ferrule 16.
In some embodiments, a height ratio H2:H1 from second end 53 to first end 43 ranges between 1.2:1 and 3:1. In some embodiments, a width ratio W2:W1 from second end 53 to first end 43 ranges between 1.2:1 and 3:1.
As mentioned previously, tapered surfaces 55 are provided between first end 43 and second end 53 of tapered divider 49. Tapered surfaces 55 connect first end 43 to second end 53 of tapered divider 49, and tapered surfaces 55 are angled with respect to longitudinal axis L1 of bore 37 and are configured to guide inserted optical fibers into bore 37. In particular, when optical fibers 67 are inserted through the second end 53 of tapered divider 49, optical fibers 67 may be off center with respect to corresponding center C of bore 37 and contact one of tapered surfaces 55. The tapered surface 55 then guides optical fiber 67 into bore 37 as optical fiber 67 is continued to be advanced within bore 37. In some embodiments, tapered surfaces 55 have an angle θ ranging between 15° and 45°. Having an angled tapered surface as shown provides the advantage of a softer vertical wall where optical fibers that are off center with center C of bore 37 are guided into alignment as the optical fiber 67 is advanced through ferrule 16. This configuration facilitates insertion of optical fibers into bores 37 and improves installation time as optical fibers are directed into bores 37. This contrasts with previous ferrule configurations where a vertical wall substantially perpendicular with longitudinal axis L1 is provided. Such a vertical wall provides a hard stop to the optical fiber 67 and can damage the inserted optical fiber 67 upon contact or hamper installation of optical fiber 67 thereby increasing installation time.
As discussed below, tapered surfaces 55 are also configured to prevent lateral misalignment of optical fibers. Stated another way, tapered surfaces 55 provide a physical barrier of inserted optical fibers to prevent optical fiber crossover into a non-corresponding bore 37. This feature of tapered surfaces 55 enables accurate positioning of optical fibers 67 with the corresponding bore 37 within ferrule 16.
In particular, adjacent tapered dividers 49 have corresponding adjacent tapered surfaces 55, and as shown in
Referring now to
Referring briefly to
Referring now to
Referring now to
In some embodiments, ferrule 16 as described is not sized to be used as an MPO connector ferrule. Stated another way, ferrule 16 may be shorter and/or thinner than a standard ferrule in an MPO connector such that ferrule 16 may be incompatible with devices designed for conventional MPO connectors. To address this challenge a converter 80 is coupled to ferrule 16 such that the form factor of the resulting assembly is similar to that of a conventional MT ferrule for MPO connectors. While an MPO connector is mentioned in the above disclosure, it is within the scope of the present disclosure that this concept may be used in other suitable connector applications.
Referring now to
Converter body 85 comprises an opening 87 extending between the front end 81 and the back end 83 and defined by the converter body 85. Opening 87 is configured to receive ferrule 16 between the front end 81 and back end 83 within converter body 85. Converter body 85 further comprises securing wedges 89 and side surfaces 91, 92 extending from a top section 93 and a bottom section 95 of converter body 85 and into opening 87. Securing wedges 89 and sides 91, 92 cooperate to hold ferrule 16 within converter 80.
Securing wedges 89 are configured to engage with ledge A and to extend into recessed portion 28 when coupling ferrule 16 to converter 80. In particular, to secure ferrule 16 to converter 80, ferrule 16 is advanced in direction A1 such that back end 21 advances into opening 87 first. Ferrule 16 continues to advance in direction A1 until ledge A is advanced further inward (towards back end 83 of converter 85) than securing wedges 85. At this point, securing wedges 89 are extending into recessed portion 28 of ferrule 16 and a vertical surface 90 of securing wedge 89 engages with ledge A to hold ferrule 16 in place and restrict movement in the z-direction as defined in the Cartesian coordinate system of the Figure.
As mentioned previously, securing wedges 89 and sides 91, 92 cooperate to hold ferrule within converter 80. In particular, side surfaces 91, 92 extend from front end 81 of converter 80 towards back end 83 of converter 80. Sides 91, 92 each comprise corresponding surfaces 91A, 92A that are configured to correspond to beveled edges 71, 72 of ferrule 16; surfaces 91A, 92A are spaced apart from each other by a width W that corresponds to a width of ferrule 16. As shown, surfaces 91A, 92A are angled with respect to longitudinal axis L, and surfaces 91A, 92A are angled such that the angle is the same as the angle of beveled edges 71, 72 with respect to longitudinal axis L. By having the same angle and being spaced apart by a width W, sides 91, 92 can accommodate the insertion of ferrule 16 along direction A1 into converter 80 whereby, surfaces 91A, 92A contact beveled edges 71, 72 of ferrule 16 and apply a force onto the inserted ferrule 16. In this way, side surfaces 91, 92 apply forces in the x-y plane that cooperate with the physical structure of converter 80 to limit the movement of ferrule 16 in the x-y plane as defined in the Cartesian coordinate system of the Figure.
Referring briefly to
Converter 80 further comprises pin holes 93, 95 that correspond to pin holes 31, 33 of ferrule 16 when ferrule 16 is inserted into converter 80. Pin holes 93, 95 are configured to align with pin holes 31, 33 of ferrule 16 and extend the length of pin holes 31, 33 to back end 83 of converter 80. In this way, pin holes 31, 33 can receive guide pins when mounting ferrule 16 within converter 80 and connector 10.
Referring briefly to
To secure converter 80 onto ferrule 16 and with reference to
After assembling ferrule assembly 70, optical fiber(s) 67 are inserted through the lead in portion 97 of converter 80 and into corresponding bore 37 of ferrule 16. In some embodiments, bonding agent 65 can be applied before, during, or after insertion of optical fiber(s) 67 into ferrule assembly 70 as discussed previously with reference to
In an alternate embodiment, to assemble connector 10, optical fiber(s) 67 are first inserted through lead in section 97 of converter 80 and through opening 87 of converter 80. Then, bonding agent 65 is applied into bores 37 of ferrule 16 such that inserted optical fiber(s) 67 are bonded to bores 37 of ferrule 16 using any of the methods discussed above with respect to
Referring now to
Converter 80A comprises a front end 81, a back end 83, and a converter body 85 extending from the front end 81 to the back end 83. Converter body 85 comprises an opening 87 extending between the front end 81 and the back end 83 and that is defined by the shape of converter body 85. Opening 87 is configured to receive ferrule 16 between the front end 81 and back end 83 within converter body 85. Converter body 85 further comprises securing wedges 89 and side surfaces 91, 92 extending from a top section 93 and a bottom section 95 of converter body 85 and into opening 87. Securing wedges 89 and sides 91, 92 cooperate to hold ferrule 16 within converter 80.
Securing wedges 89 are configured to engage with ledge A and to extend into recessed portion 28 when coupling ferrule 16 to converter 80. In particular, a vertical surface 90 of securing wedge 89 engages with ledge A to hold ferrule 16 in place and restrict movement in the z-direction as defined in the Cartesian coordinate system of the Figure. In addition, as shown, converter 80A further includes a second securing wedge 98 that contacts back end 21 of ferrule 16. In particular, second securing wedge 98 includes a vertical surface 99 that contacts back end 21 of ferrule 16. In this way, second securing wedge 98 engages with back end 21 of ferrule 16 to hold ferrule 16 in place and restrict movement in the z-direction as defined in the Cartesian coordinate system of the Figure. While a second securing wedge 98 is shown in
To further secure ferrule within converter 80A, sides 91, 92 extend from front end 81 of converter 80 towards back end 83 of converter 80. Sides 91, 92 each comprise corresponding surfaces 91A, 92A that are configured to correspond to beveled edges 71, 72 of ferrule 16 as discussed below. In addition, surfaces 91A, 92A are spaced apart from each other by a width that corresponds to a width of ferrule 16. As shown, surfaces 91A, 92A are angled with respect to longitudinal axis L, and surfaces 91A, 92A are angled with respect to longitudinal axis L such that the angle is the same as the angle of beveled edges 71, 72. By having the same angle and being spaced apart by the width of ferrule 16, sides 91, 92 can accommodate ferrule 16 into converter 80A whereby, surfaces 91A, 92A contact beveled edges 71, 72 of ferrule 16 and apply a force onto the inserted ferrule 16. In this way, side surfaces 91, 92 apply forces in the x-y plane that cooperate with the physical structure of converter 80A to limit the movement of ferrule 16 in the x-y plane as defined in the Cartesian coordinate system of the Figure.
Referring briefly to
Converter 80A further comprises pin holes 93, 95 that correspond to pin holes 31, 33 of ferrule 16 when ferrule 16 is inserted into converter 80A. Pin holes 93, 95 are configured to align with pin holes 31, 33 of ferrule 16 and extend the length of pin holes 31, 33 to back end 83 of converter 80A. In this way, pin holes 31, 33 can receive guide pins when mounting ferrule 16 within converter 80A and connector 10.
Referring briefly to
To apply converter 80A onto ferrule 16, converter 80A is overmolded onto ferrule 16. In some embodiments, converter 80A is directly molded onto ferrule 16 in a secondary molding operation. Advantageously, by molding converter 80A onto ferrule 16, features of ferrule 16 create the bonding geometry/configuration that keep ferrule 16 and converter 80A coupled to each other during their respective lifetimes. For example, the location of ledge A and recessed portion 28 of ferrule 16 creates the geometry of converter 80A to enable converter 80A to couple to ferrule 16.
Because these and other variations, modifications, combinations, and sub-combinations of the disclosed embodiments may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.
This application claims the benefit of priority of U.S. Provisional Application No. 63/399,814, filed on Aug. 22, 2022, the content of which is relied upon and incorporated herein by reference in its entirety.
Number | Date | Country | |
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63399814 | Aug 2022 | US |