WO2019036297A1

WO2019036297A1 - Ferrule assembly and fiber optic connection system

Info

Publication number: WO2019036297A1
Application number: PCT/US2018/046262
Authority: WO
Inventors: Guan Peng HU; Liming Wang; Yu Lu
Original assignee: Commscope Technologies Llc
Priority date: 2017-08-15
Filing date: 2018-08-10
Publication date: 2019-02-21
Also published as: CN109407218A

Abstract

The present invention relates to ferrule assembly and fiber optic connection system. A ferrule assembly comprising: a ferrule body having an end face; a plurality of optical fibers supported by the ferrule body, the optical fibers having fiber ends adjacent the end face of the ferrule body; and first and second alignment pins supported by the ferrule body, the first and second alignment pins having projection portions that project outwardly beyond the end face of the ferrule body, the projection portion of at least the first alignment pin having a radially deformable construction that permits the projection portion to deform radially inwardly relative to a central longitudinal axis of the alignment pin when the projection portion is inserted into an alignment opening of another ferrule.

Description

FERRULE ASSEMBLY AND FIBER OPTIC CONNECTION SYSTEM

Cross-Reference to Related Application

This application is being filed on August 10, 2018 as a PCT International Patent Application and claims the benefit of Chinse Patent Application No.

201710694150.0, filed on August 15, 2017, the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates generally to fiber optic connectors for making optical connections between optical fibers. More particularly, the present disclosure relates to multi-fiber optical connectors for making optical connections between pluralities of optical fibers. In particular, the present disclosure relates to ferrule assembly and fiber optic connection system.

Background

Fiber optic connectors are used to make optical connections between optical fibers. An advantage of making optical connections with fiber optic connectors, as compared to using splicing, is that the optical connections can easily be connected and disconnected as needed. Fiber optic connectors can include single-fiber optical connectors and multi-fiber optical connectors. When two single-fiber optical connectors are coupled together, single fibers corresponding to each of the optical connectors are coaxially aligned and optically coupled to one another. When two multi-fiber optical connectors are coupled together, a plurality of optical fibers corresponding to one of the multi-fiber optical connectors is placed into alignment with a plurality of optical fibers corresponding to the other multi-fiber optical connector. Typically, the optical fibers of the optical connectors are supported within relatively rigid structures called ferrules. To reduce optical losses, it is desirable for the ferrules of connected optical connectors to be relatively precisely aligned so that the corresponding optical fibers supported within the ferrules are also relatively precisely aligned. Such precise alignment assists in reducing signal loss. Figure 1 illustrates an example prior art fiber optic connection system 20. The fiber optic connection system includes two multi-fiber optical connectors 22 that are mechanically coupled together by an intermediate fiber optic adapter 24. Multi-fiber optical connectors 22 of the type shown at Figure 1 can be referred to as Multi-fiber Push On (MPO) connectors. Each of the multi-fiber optical connectors 22 includes a ferrule 26 supporting a plurality of optical fibers 28. The optical fibers 28 correspond to fiber optic cables 30 that are terminated by the multi-fiber optical connectors 22. When the multi- fiber optical connectors 22 are connected together via the fiber optic adapter 24, precise alignment between the ferrules 26 of the optical connectors 22 is achieved through a pin and socket arrangement. For example, as shown at Figure 1, one of the optical connectors 22 is a male fiber optic connector and includes alignment pins 32 carried with its corresponding ferrule 26. The other optical connector 22 is a female fiber optic connector and includes alignment openings 34 (i.e., sockets) defined by the corresponding ferrule 26. When the optical connectors 22 are coupled together, the alignment pins 32 fit within the alignment openings 34 to provide alignment between the ferrules 26 of the interconnected optical connectors 22. The alignment pins 32 are solid alignment pins and are not designed to radially deform when inserted into the alignment openings 34. Instead, the alignment pins 32 have outer diameters that are slightly smaller than the diameters of the alignment openings 34. To achieve effective alignment between the ferrules 26 of the mated optical connectors 22, it is desirable for the tolerances between the alignment openings 34 and the alignment pins 32 to be precise. Such precision can be difficult to maintain and typically results in relatively high manufacturing costs. Additionally, even with precise manufacturing of the alignment pins 32 and the alignment openings 34, the difference in size between the outer diameters of the alignments pins 32 and the diameters of the alignment openings 34 allows for limited movement of the pins 32 within the openings 34 which can negatively affect optical performance.

Summary

One aspect of the present disclosure relates to an alignment pin for a fiber optic connector. In one example, the alignment pin is deformable in a radial orientation such that the alignment pin is capable of radially deforming to a smaller outer cross- sectional size when inserted within a corresponding alignment opening. It is preferred for the alignment pin to be used with a ferrule of a multi-fiber optical connector. It is preferred for two alignment pins having radially deformable attributes to be used for each multi-fiber optical connector, but in other examples one of the alignment pins can have the radially deformable construction while the other alignment pin can have a more rigid construction.

Another aspect of the present disclosure relates to an alignment pin for aligning a ferrule of a fiber optic connector with a mating ferrule. In one example, the alignment pin defines at least one longitudinal slot/groove which extends lengthwise through at least a portion of the alignment pin (e.g., along a projection portion of the alignment pin) for allowing the alignment pin to deform such that an outer cross-sectional size of the alignment pin reduces when the alignment pin is inserted into a corresponding alignment opening of a mating ferrule. In certain examples, the alignment pin can include more than one longitudinal groove. In certain examples, the alignment pin can include two alignment grooves positioned on opposite sides of the alignment pin. In certain examples, the two grooves can be offset approximately 180 degrees relative to one another about a central longitudinal axis of the alignment pin. In certain examples, the alignment pin can have only one longitudinal groove and it can also include a hollow core. In certain examples, the alignment pin can be cylindrical and can include a circular outer cross- sectional profile prior to deformation. In certain examples, the alignment pin can have a rounded free end. In certain examples, the alignment pin can have a base end with a notch for axially fixing the alignment pin relative to a pin holder. In certain examples, two of the alignment pins can be secured to a multi-fiber ferrule. In certain examples, the multi- fiber ferrule can include openings for receiving a plurality of optical fibers located between the alignment pins. In certain examples, the alignment pin or pins can be used on ferrules that support four to twenty-four optical fibers. In certain examples, fibers can be arranged in rows. In certain examples, the pins are used to provide alignment between the ferrules of two MPO connectors.

Another aspect of the present disclosure relates to a fiber optic connection system including a male ferrule supporting a plurality of optical fibers and a female ferrule supporting a plurality of optical fibers. The female ferrule defines at least two alignment openings. The male ferrule includes at least two alignment pins adapted to fit within the alignment openings. At least one of the alignment pins has a pre-inserted outer cross- sectional profile that is larger than a cross-sectional profile of the corresponding alignment opening into which the alignment pin is inserted to provide alignment between the male and female ferrules. The alignment pin has a deformable construction that allows the outer cross-sectional profile of the alignment pin to reduce in size when the alignment pin is inserted into its corresponding alignment opening. In certain examples, the alignment pin has an elastic construction and elastically deforms from a pre-inserted enlarged cross- sectional profile to a smaller inserted outer cross-sectional profile. It will be appreciated that the inserted outer cross-sectional profile can have at least one outer cross-dimension that is smaller than a corresponding outer cross-dimension of the pre-inserted outer cross- sectional profile. Because the pin is elastically deformed from the pre-inserted outer cross-sectional profile to the inserted outer cross-sectional profile, the deformed pin applies spring load within the alignment opening as the inherent elasticity of the construction of the pin urges the pin back towards the pre-insertion outer cross-sectional profile against the constraint of the alignment opening. In certain examples, the alignment pin is made of a material having a composition that includes a metal (e.g., stainless steel).

Another aspect of the present disclosure relates to a fiber optic connection system including first and second ferrules each supporting at least one optical fiber. The first and second ferrules are adapted to mate together to optically connect their

corresponding optical fibers. The first ferrule includes at least one alignment pin and the second ferrule includes at least one alignment opening for receiving the alignment pin. The alignment pin is oversized with respect to the alignment opening. The alignment pin undergoes a forced size reduction when the alignment pin is inserted into the alignment opening. In one example, the forced size reduction can be accommodated through deformation (e.g., elastic deformation) of the alignment pin.

Still another aspect of the present disclosure relates to an alignment pin for a ferrule that is oversized with respect to a corresponding alignment opening intended to receive the alignment pin.

According to the present disclosure, there is provided a ferrule assembly comprising: a ferrule body having an end face; a plurality of optical fibers supported by the ferrule body, the optical fibers having fiber ends adjacent the end face of the ferrule body; and first and second alignment pins supported by the ferrule body, the first and second alignment pins having projection portions that project outwardly beyond the end face of the ferrule body, the projection portion of at least the first alignment pin having a radially deformable construction that permits the projection portion to deform radially inwardly relative to a central longitudinal axis of the alignment pin when the projection portion is inserted into an alignment opening of another ferrule.

According to the present disclosure, there is provided a fiber optic connection system comprising: a female fiber optic connector comprising: a ferrule body having an end face, the ferrule body defining first and second alignment openings having open ends at the end face, the first and second alignment openings having transverse cross- sectional shapes; and a plurality of optical fibers supported by the ferrule body, the optical fibers having fiber ends adjacent the end face of the ferrule body; and a male fiber optic connector comprising: a ferrule body having an end face; a plurality of optical fibers supported by the ferrule body, the optical fibers having fiber ends adjacent the end face of the ferrule body; and first and second alignment pins supported by the ferrule body, the first and second alignment pins having projection portions that project outwardly beyond the end face of the ferrule body, the projection portions of the alignment pins being configured to fit respectively within the first and second alignment openings of the female fiber optic connector to provide alignment between the ferrule body of the female fiber optic connector and the ferrule body of the male fiber optic connector, at least the projection portions of the first and second alignment pins having radially deformable constructions that permit the projection portions to deform radially inwardly relative to corresponding central longitudinal axes of the first and second alignment pin when the projection portions are inserted into the first and second alignment openings of the female fiber optic connector, the projection portions having pre-inserted outer transverse cross- section shapes that define cross-dimensions that are larger than corresponding cross- dimensions of the transverse cross-sectional shapes of the first and second alignment openings, and the projection portions having inserted outer transverse cross-section shapes that define cross-dimensions none of which are larger than corresponding cross- dimensions of the transverse cross-sectional shapes of the first and second alignment openings.

According to the present disclosure, there is provided a fiber optic connection system comprising: first and second ferrules each supporting at least one optical fiber, the first ferrule supporting an alignment pin and the second ferrule defining an alignment opening for receiving the alignment pin, the alignment pin being oversized with respect to the alignment opening, and the alignment pin being forced to smaller size when inserted in the alignment opening.

A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the examples disclosed herein are based. Brief Description of the Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate aspects of the present disclosure and together with the description, serve to explain the principles of the disclosure. A brief description of the drawings is as follows:

Figure 1 illustrates a prior art fiber optic connection system;

Figure 2 illustrates a multi-fiber ferrule having alignment pins in accordance with the principles of the present disclosure;

Figure 3 illustrates the alignment pins of the multi -fiber ferrule of Figure 2 with base ends of the pins supported by a pin holder;

Figure 4 is a perspective view of one of the alignment pins of the multi- fiber ferrule of Figure 2 taken from a free end of the alignment pin;

Figure 5 is a perspective view of the alignment pin of Figure 4 taken from a base end of the alignment pin;

Figure 6 is a side view of the alignment pin of Figure 4 taken from a view

90 degrees offset from a longitudinal groove of the alignment pin;

Figure 7 is a side view of the alignment pin of Figure 4 taken from a view 180 degrees offset from the longitudinal groove of the alignment pin;

Figure 8 is a side view of the alignment pin of Figure 4 taken from a view in line with the longitudinal groove of the alignment pin;

Figure 9 is an end view of the free end of the alignment pin of Figure 4;

Figure 10 is an end view of the base end of the alignment pin of Figure 4;

Figure 11 is a cross-sectional view taken along section line 11-11 of Figure

9;

Figure 12 is a cross-sectional view taken along section line 12-12 of Figure

9;

Figure 13 is a cross-sectional view taken along section line 13-13 of Figure

8;

Figure 14 is a cross-sectional view taken along a plane that bisects the alignment pins of the assembly of Figure 3;

Figure 15 is a cross-sectional view showing the multi -fiber ferrule of Figure 2 incorporated into a male multi-fiber optical connector;

Figure 16 is a cross-sectional view showing a fiber optic connection system including the male multi-fiber optical connector of Figure 15 shown aligned with a corresponding female multi-fiber optical connector and also showing a fiber optic adapter positioned between the male and female multi-fiber optical connectors;

Figure 17 is a cross-sectional view showing the male and female multi -fiber optical connectors of Figure 16 being mechanically coupled together by the intermediate fiber optic adapter;

Figure 18 is a cross-sectional view taken along section line 18-18 showing the alignment pins of the male multi-fiber optical connector deformed to an inserted outer cross-sectional shape/profile that is reduced in size (e.g., radially constricted, radially inwardly deformed, inwardly compressed, etc.) as compared to a pre-insertion outer cross- sectional shape/profile as shown by Figure 13;

Figure 18A is an enlarged view of the alignment pin having the inserted outer cross-sectional shape;

Figure 19 is a perspective view from a base end of another alignment pin in accordance with the principles of the present disclosure;

Figure 20 is a side view of the alignment pin of Figure 19;

Figure 21 is a base end view of the alignment pin of Figure 19;

Figure 22 is a cross-sectional view taken along section line 22-22 of Figure

21;

Figure 23 is a cross-sectional view taken along section line 23-23 of Figure 20; and

Figure 24 is another alignment pin in accordance with the principles of the present disclosure.

Detailed Description

Figure 2 illustrates a ferrule assembly 40 in accordance with the principles of the present disclosure. The ferrule assembly 40 includes a ferrule body 42, a pin holder 44, and two alignment pins 46. The ferrule body 42 includes an end face 48 positioned opposite from a base 51. The pin holder 44 mounts at the base 51. The ferrule body 42 defines a plurality of fiber openings 52 for receiving optical fibers. The optical fibers can include single mode optical fibers or multi-mode optical fibers. The fiber openings 52 are positioned between the alignment pins 46. It will be appreciated that, depending upon the application, ferrule bodies can typically be used to support four to twenty-four optical fibers, although more than twenty-four optical fibers also can be supported. In the depicted case, the ferrule body 42 is adapted to accommodate twelve optical fibers. If more than twelve optical fibers are to be supported, then the ferrule body would typically include multiple rows of fiber openings.

In the depicted example, the end face 48 is shown perpendicular relative to the alignment pins 46. In other examples, end face 48 can be otherwise angled relative to the alignment pins 46. As an example, the end face 48 can be angled about 8 degrees from perpendicular relative to the alignment pins 46.

It will be appreciated that the ferrule body 42 is generally rectangular. As depicted, the ferrule body 42 can include a length L, a width W, and a depth D. The ferrule body 42 can define a major axis 43 along the length L and a minor axis 45 aligned along the width W. The major and minor axes 43, 45 can intersect at a center of the ferrule body 42 and can be perpendicular relative to each other. The optical fibers and the alignment pins 46 can extend along the depth D. The alignment pins 46 can be separated from one another along the length L and can be aligned along the major axis 43. The fiber openings 52 can be positioned along rows that extend along the length L at a location generally between the alignment pins 46. In one example, the ferrule body 42 can have a material composition that includes a plastic, such as a thermo-plastic. In one example, the plastic can include a glass-filled plastic. In one example, the thermo-plastic can include polyphenylene sulfide.

The ferrule body 42 also can include pin mounting openings 54 that are preferably parallel to the fiber openings 52 and that extend along the depth D. The alignment pins 46 preferably are secured within the openings 54. Base ends 56 (Figure 5) of the alignment pins 46 can be secured to the pin holder 54. In certain examples, alignment pins 46 can include notches 58 (see Figure 12 and 14) that interlock or otherwise engage with the pin holder 54 to limit axial movement of the alignment pins 46 along the depth dimension D. The alignment pins 46 also include projection portions 50 that project outwardly beyond the end face 48.

It will be appreciated that the alignment pins 46 have a radially deformable construction that allows the outer transverse cross-sectional shapes of the alignment pins 46 to deform radially inwardly when the alignment pins 46 are inserted within

corresponding alignment openings of a female ferrule. The radially deformable construction can be provided by mechanical features or structures such as outer recesses (e.g., one or more longitudinal grooves having open outer sides), and/or hollow portions (e.g., hollow cores, hollow channels) and/or other types of structures that involve the selective removal/elimination of material to promote/enhance the radial deformability of the pin. For the sake of manufacturing efficiency, it is preferred for the mechanical features to run consistently along the entire length of the alignment pins, but in certain examples the mechanical features may be provided along a portion or portions of the length of a given alignment pin (e.g., along the projection portion 50). In other examples, the radial deformable construction of the alignment pins 46 may be provided through material selection. For example, the alignment pins may be made by a material having a composition with inherent deformable physical attributes that allow the alignment pins to deform to a reduced radial size when inserted into alignment openings. The composition can include a composite composition including more than one material or a homogeneous composition including only one type of material consistent throughout. The compositions can include metal materials and combinations of plastic and metal materials. In certain examples, a combination of material selection and mechanical features are used to provide the alignment pins with suitable degrees of radial deformability.

In certain examples, the alignment pins 46 are constructed of a material such as metal having elastic characteristics. Thus, the deformation of the outer transverse cross-sectional profiles of the alignment pins 46 is preferably primarily elastic in nature such that the outer transverse cross-sectional shapes of the alignment pins 46 will spring back to an enlarged, pre-inserted outer cross-sectional shape when the alignment pins 46 are removed from the alignment openings of the corresponding female ferrule. In one example, the alignment pins 46 have a composition that includes a metal material, such as stainless steel.

Referring to Figure 3, the alignment pins 46 have mechanical features designed to allow the alignment pins 46 to radially inwardly deform when inserted into corresponding alignment openings. The deformation can include a radially inward constriction relative to a central longitudinal axis 62 (Figure 4) of each of the alignment pins 46. In one example, a mechanical feature for allowing the alignment pins 46 to radially inwardly deform upon insertion into the alignment openings can include a longitudinal groove 64. The longitudinal groove 64 can be an outer groove having an outwardly facing open side 66 (see Figure 13). The longitudinal groove 64 can have a length that extends parallel to the central longitudinal axis 62 and a groove width GW (see Figure 13) that extends generally in a circumferential orientation relative to the central longitudinal axis 62. The grooves 64 preferably extend at least along the projection portions 50 of the alignment pins 46. As depicted, the longitudinal grooves 64 extend lengthwise throughout the length of each of the alignment pins 46. In the arrangement of Figures 2 and 14, the alignment pins 46 are positioned on the major axis 43 and the open sides 66 of the grooves 64 face outwardly in opposite directions from one another. In the depicted example, each of the alignment pins 46 includes only one of the longitudinal grooves 64. As depicted, the open side 66 of the groove 64 of a left one of the alignment pins 46 can face in a leftward direction, and an open side 66 of the groove 64 of a right one of the alignment pins 46 can face in a rightward direction.

Referring to Figures 4-13, a free end 68 of each alignment pin 46 can be curved or rounded as to have a dome-like configuration that terminates at an apex. This type of rounded or tapered configuration facilitates inserting the alignment pins 46 in the corresponding alignment openings by providing a guiding/lead-in function. In the depicted example, the alignment pins 46 have outer shapes that are generally cylindrical along the vast majority of the lengths of the alignment pins 46. As shown at Figure 13, the alignment pins 46 have pre-insertion outer transverse cross-sectional shapes 70 that are generally circular in shape and have a cross-dimension CDi (e.g., an outer diameter). The pre-insertion transverse cross-sectional shapes and cross-dimensions CDi are preferably larger than corresponding transverse cross-sectional shapes of the alignment openings into which the alignment pins 46 are intended to be inserted. As shown at Figure 13, the alignment pins 46 can also include hollow cores 72 in communication with the

longitudinal grooves 64. The hollow cores 72 can be enlarged compared to the grooves 64 and optionally can extend through the entire length of each alignment pin 46. In certain examples, the hollow cores 72 and the pre-insertion transverse outer cross-sectional shapes 70 can be concentric with respect to the center axis 62. In certain examples, the hollow cores 72 can be cylindrical in shape and can have circular transverse cross-sectional shapes. In certain examples, a cross-dimension CD₂ (e.g., diameter) of the hollow core 72 can be larger than the groove width GW of the longitudinal groove 64. In certain examples, groove 64 has a length that extends completely along the entire length of the alignment pin 46 from the base end 56 to the free end 68. In certain examples, the hollow core 72 can have a transverse cross-sectional shape that matches the outer transverse cross-sectional shape of the alignment pin 46 such that the alignment pin 46 is defined by a wall 78 of constant thickness T that curves circumferentially around the central longitudinal axis 62 of the alignment pin 46. A groove depth GD of the groove 64 extends through the wall 78 from an outside of the alignment pin 46 to the hollow core 72. The groove depth DG corresponds to the thickness T of the wall 78. Figure 14 is a cross-sectional view showing how the alignment pins 46 interlock with the pin holder 44. In this example, shoulders 80 of the pin holder 44 fit within the notches 58 of the alignment pins 46. It will be appreciated that the notches 58 are located at opposite sides of the alignment pins 46 from the open sides 66 of the grooves 64. In other words, the notches 58 are offset about 180 degrees about the central longitudinal axis 62 from the open side 66 of the grooves 64.

Figure 15 shows a multi-fiber optical connector 90 incorporating the ferrule assembly 40 of Figure 2. The multi -fiber optical connector 90 includes a connector body 91 having a front end 94 and a rear end 96. The connector body 91 includes a front housing 92 and a rear housing 98 that attaches to a rear end of the front housing 92. A plurality of optical fibers 100 are routed into the multi -fiber optical connector 90 through the rear housing 98. The optical fibers 100 include front end portions 102 that are bonded or otherwise secured within the fiber openings 54 of the ferrule body 42. A boot 104 can mount on a rear end of the rear housing 98 and can function to provide strain relief with respect to a cable which includes the optical fibers 100. The rear housing 98 can function as a spring-stop for a spring 99 that is captured between the rear housing 98 and the rear of the ferrule assembly 40. In this way, the spring 99 biases the ferrule assembly 40 in a forward direction relative to the housing of the multi-fiber optical connector 90. The connector body 91 includes recesses 106 for receiving latches 108 of a fiber optic adapter 110 for mechanically coupling the multi-fiber optical connector 90 to a corresponding female multi-fiber optical connector 112 (see Figure 16). The multi-fiber optical connector 90 further includes a release sleeve 114 that can be pulled rearwardly relative to the connector body 91 of the multi -fiber fiber optic connector 90 to provide clearance for allowing the latches 108 to flex outwardly to allow for removal of the multi -fiber optical connector 90 from the adapter 110.

The female multi -fiber optical connector 1 12 has the same basic structure as the male multi-fiber optical connector 90, except its ferrule 120 has alignment openings 122 instead of alignment pins. The ferrule 120 supports optical fibers 100 positioned between the alignment openings 122. When the male multi-fiber optical connector 90 and the female multi -fiber optical connector 112 are mated together through the fiber optic adapter 110 as shown at Figure 17, the optical fibers of the male multi -fiber optical connector 90 are optically coupled to the optical fibers of the female multi -fiber optical connector 112. Effective alignment between the coupled optical fibers is provided through the interface between the alignment pins 46 of the male multi-fiber optical connector 90 and the alignment openings 122 of the female multi-fiber optical connector 112. It will be appreciated that the alignment openings 122 of the female multi -fiber optical connector 112 have a transverse cross-sectional shape that is smaller than the pre-insertion outer transverse cross-sectional shape 70 (see Figure 13) of the alignment pins 46. Thus, for the projection portions 50 of the alignment pins 46 to fit within the alignment openings 122, it is necessary for the projection portions 50 of the alignment pins 46 to deform radially inwardly to a size that is compatible with, and optionally at least partially conforms to, the transverse cross-sectional shape of the alignment openings 122. When the fiber optic connectors 90, 112 are mated together, the alignment pins 46 are forced axially into the alignment openings 122. As the projection portions 50 of the alignment pins 46 are forced axially into the alignment openings 122, the projection portions 50 are forced to deform radially inwardly such that one or more outer cross-dimensions of the projection portions 50 are equal to a corresponding cross-dimension of the alignment openings 122, and none of the outer cross-dimensions of the projection portions 50 are larger than corresponding cross-dimensions of the alignment openings 122. Preferably, the inward deformation of the alignment pins 46 is elastic in nature such that when the projection portions 50 of the alignment pins 46 are deformed radially within the alignment openings 122, the deformed projection portions 50 exert an outward radial spring-load that is applied within the alignment openings 122 to the portion of the ferrule body defining the openings 122. This spring-load provides a snug and secure fit between the alignment pins 46 and the alignment openings 122.

As indicated above, deformation of the alignment pins 46 is preferably primarily elastic in nature. Thus, when the fiber optic connectors 90, 112 are disconnected from one another, the alignment pins 46 preferably elastically return from the reduced-in- size inserted outer transverse cross-sectional shape to the enlarged pre-insertion outer transverse cross-sectional shape. Figures 18 and 18A show the projection portions 50 of the alignment pins 46 in a radially inwardly deformed state. In this state, the alignment pins 46 have been compressed radially inwardly from the pre-insertion outer transverse cross-sectional shape of Figure 13 into the inserted outer transverse cross-sectional shape (see Figure 18A). It will be appreciated that the groove 64 and the hollow core 72 allows the wall 78 of the alignment pin 46 to flex at region 79 causing the groove width GW of the longitudinal groove 64 to slightly decrease and also causing the outer circumferential size of the alignment pin to decrease to a state where the alignment pin 46 can fit within the alignment opening 122. Figures 19-23 show another alignment pin 246 in accordance with the principles of the present disclosure. Alignment pin 246 includes an alternative structure for allowing the outer shape of the alignment pin 246 to radially constrict, radially deform, or otherwise become circumferentially smaller so as to allow the alignment pin 246 to fit within an alignment opening that is smaller than the pre-insertion size of the alignment pin. In the depicted example, the alignment pin 246 does not have a hollow core. Instead, the alignment pin 246 includes deformation grooves 247 positioned on circumferentially opposite sides of the alignment pin 246. In one example, the grooves 247 are positioned approximately 180 degrees circumferentially offset from one another. In other examples, other degrees of offset can be provided between the grooves. Additionally, in other examples, three, four, or more grooves can be provided. The grooves 247 extend at least along a projection portion of the alignment pin 246, and preferable extend along the entire length of the alignment pin. The grooves 247 are configured to allow the outer shape (e.g., the outer transverse cross-sectional shape) of the alignment pin 246 to deform radially inwardly to allow for insertion of the alignment pin into a smaller alignment opening. It will be appreciated that the alignment pin 246 can be used in ferrule assemblies and fiber optic connectors in the same way described with respect to the alignment pins 46.

Figure 24 shows another alignment pin 346 in accordance with the principles of the present disclosure. The alignment pin 346 has a solid, non-grooved construction. Rather than having grooves or a hollow core for enhancing the radial deformability of the pin 346, the pin 346 is constructed of a material (e.g., plastic) having a modulus of elasticity suitable for allowing the pin to radially deform to a smaller size when inserted into an undersized alignment opening.

With regard to the pin deformation described herein, it will be appreciated that the deformation does not need to be uniform circumferentially around the pin.

Instead, some regions or portions can deform more than others. Additionally, it is not necessary for the outer transverse cross-sectional shape of the alignment pin to completely form to, complement, or match the transverse cross-sectional shape of the alignment opening. Instead, portions of the outer circumferential shape of the alignment pin may directly contact the portion of the ferrule body defining the alignment openings while other portions do not contact the ferrule body. In other examples, the outer transverse cross-sectional shape of the alignment pin may generally conform with and be in contact with the portion of the ferrule defining the alignment opening. Various modifications and alterations of this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure, and it should be understood that the scope of this disclosure is not to be unduly limited to the illustrated examples set forth herein

Claims

What is claimed is:

1. A ferrule assembly comprising:

a ferrule body having an end face;

a plurality of optical fibers supported by the ferrule body, the optical fibers having fiber ends adjacent the end face of the ferrule body; and

first and second alignment pins supported by the ferrule body, the first and second alignment pins having projection portions that project outwardly beyond the end face of the ferrule body, the projection portion of at least the first alignment pin having a radially deformable construction that permits the projection portion to deform radially inwardly relative to a central longitudinal axis of the alignment pin when the projection portion is inserted into an alignment opening of another ferrule.

2. The ferrule assembly of claim 1, wherein the first and second alignment pins both have the radially deformable construction.

3. The ferrule assembly of claim 1, wherein the radially deformable construction permits the projection portion to elastically deform radially inwardly relative to the central longitudinal axis.

4. The ferrule assembly of claim 1, wherein the radially deformable construction allows the projection portion to deform between a pre-insertion outer transverse cross- sectional shape and an inserted outer transverse cross-sectional shape, and wherein the pre-insertion outer transverse cross-sectional shape has at least one cross-dimension that is larger than a corresponding cross-dimension of the inserted outer transverse cross- sectional shape.

5. The ferrule assembly of claim 1, wherein the first alignment pin includes the radially deformable construction along all or substantially all of its length.

6. The ferrule assembly of claim 1, wherein the first alignment pin is solid without a longitudinal groove, and wherein the radially deformable construction is provided by constructing at least the projection portion of the first alignment pin of a material or materials that can be elastically compressed to a reduced radial size when the projection portion is inserted into the alignment opening.

7. The ferrule assembly of claim 6, wherein the projection portion has a composite construction.

8. The ferrule assembly of claim 6, wherein the projection portion has a

homogeneous construction.

9. The ferrule assembly of claim 1, wherein the radially deformable construction is provided by at least one longitudinal groove defined along a length of at least the projection portion of the first alignment pin.

10. The ferrule assembly of claim 9, wherein the first alignment pin has a length, and wherein the longitudinal groove extends along all or substantially all of the length of the first alignment pin.

11. The ferrule assembly of claim 1, wherein the radially deformable construction is provided by a hollow core of the first alignment pin defined along a length of at least the projection portion.

12. The ferrule assembly of claim 11, wherein the first alignment pin has a length, and wherein the hollow core extends along all or substantially all of the length of the first alignment pin.

13. The ferrule assembly of claim 1, wherein the radially deformable construction includes at least one longitudinal groove defined by the first alignment pin, and wherein the radially deformable construction also includes a hollow core defined by the first alignment pin, the longitudinal groove being in communication with the hollow core.

14. The ferrule assembly of claim 13, wherein the hollow core has a cross-sectional shape that is concentric with an outer cross-sectional shape of the first alignment pin, wherein the cross-sectional shape of the hollow core and the outer cross-sectional shape of the first alignment pin are circular, and wherein the cross-sectional shape of the hollow core has a diameter larger than a width of the longitudinal groove.

15. The ferrule assembly of claim 1, wherein the first and second alignment pins each have radially deformable constructions provided at least in part by a longitudinal groove.

16. The ferrule assembly of claim 15, where the longitudinal grooves have open sides, and wherein the open side of the longitudinal groove of the first alignment pin faces in an opposite direction as compared to the open side of the longitudinal groove of the second alignment pin.

17. The ferrule assembly of claim 16, where each of the first and second alignment pins includes only one of the longitudinal grooves.

18. The ferrule assembly of claim 15, wherein the ferrule body is generally rectangular and has a length that extends along a major axis and a width that extends along a minor axis that is perpendicular to the major axis, wherein the first and second pins are aligned along the major axis.

19. The ferrule assembly of claim 1, wherein the radially deformable construction is provided by a plurality of longitudinal grooves defined along a length of at least the projection portion of the first alignment pin.

20. The ferrule assembly of claim 19, wherein the longitudinal grooves are parallel to one another and circumferentially spaced relative to one another about the central longitudinal axis of the first alignment pin.

21. The ferrule assembly of claim 20, wherein the plurality of longitudinal grooves includes two longitudinal grooves, and wherein the longitudinal grooves are

circumferentially spaced 180 degrees from one another about the central longitudinal axis.

22. A fiber optic connection system comprising:

a female fiber optic connector comprising: a ferrule body having an end face, the ferrule body defining first and second alignment openings having open ends at the end face, the first and second alignment openings having transverse cross-sectional shapes; and a plurality of optical fibers supported by the ferrule body, the optical fibers having fiber ends adjacent the end face of the ferrule body; and

a male fiber optic connector comprising:

a ferrule body having an end face;

first and second alignment pins supported by the ferrule body, the first and second alignment pins having projection portions that project outwardly beyond the end face of the ferrule body, the projection portions of the alignment pins being configured to fit respectively within the first and second alignment openings of the female fiber optic connector to provide alignment between the ferrule body of the female fiber optic connector and the ferrule body of the male fiber optic connector, at least the projection portions of the first and second alignment pins having radially deformable constructions that permit the projection portions to deform radially inwardly relative to corresponding central longitudinal axes of the first and second alignment pin when the projection portions are inserted into the first and second alignment openings of the female fiber optic connector, the projection portions having pre-inserted outer transverse cross-section shapes that define cross-dimensions that are larger than corresponding cross-dimensions of the transverse cross-sectional shapes of the first and second alignment openings, and the projection portions having inserted outer transverse cross-section shapes that define cross-dimensions none of which are larger than corresponding cross-dimensions of the transverse cross-sectional shapes of the first and second alignment openings.

23. The fiber optic connection system of claim 22, wherein the radially deformable constructions of the first and second alignment pins include at least one longitudinal groove defined by each of the first and second alignment pins.

24. The fiber optic connection system of claim 22, wherein the radially deformable constructions of the first and second alignment pins include a plurality of circumferentially spaced-apart and parallel grooves defined by each of the first and second alignment pins.

25. The fiber optic connection system of claim 22, wherein the radially deformable constructions of the first and second alignment pins include hollow cores defined by each of the first and second alignment pins.

26. The fiber optic connection system of claim 22, wherein the radially deformable constructions of the first and second alignment pins include hollow cores and open sided grooves defined by each of the first and second alignment pins.

27. The fiber optic connection system of claim 22, wherein the radially deformable constructions of the first and second alignment pins are provided by constructing the first and second pins of a deformable material having physical properties that allow the material to deform to a smaller size when the projection portions of the first and second alignment pins are inserted into the first and second alignment openings.

28. A fiber optic connection system comprising:

first and second ferrules each supporting at least one optical fiber, the first ferrule supporting an alignment pin and the second ferrule defining an alignment opening for receiving the alignment pin, the alignment pin being oversized with respect to the alignment opening, and the alignment pin being forced to smaller size when inserted in the alignment opening.

29. The fiber optic connection system of claim 28, wherein the alignment pin defines one or more grooves for allowing the alignment pin to radially deform to the smaller size when the alignment pin is inserted into the alignment opening.

30. The fiber optic connection system of claim 28, wherein the alignment pin has a hollow core for allowing the alignment pin to radially deform to the smaller size when the alignment pin is inserted into the alignment opening.

31. The fiber optic connection system of claim 28, wherein the alignment pin is constructed of a plastic material having a modulus of elasticity suitable for allowing the alignment pin to radially deform to the smaller size when inserted in the alignment opening.

32. The fiber optic connection system of claim 28, wherein the alignment pin has both a hollow core and one or more open-sided grooves for allowing the alignment pin to radially deform to the smaller size when the alignment pin is inserted into the alignment opening.