Patent Description:
By definition, duplex connectors can only accommodate two optical fiber ferrules (and hence, two optical fibers). This also provides a limitation on how many channels may be interfaced with the transceiver. Conventional non-duplex multi-fiber ferrules, such as the ubiquitous MT-ferrule, has a footprint that allows only one MT-ferrule to interface with the transceiver. For example, the MT-ferrule has shoulder(s) at the back that help the MT ferrule seat inside a typical MPO connector housing, in which the ferrule is used. The shoulder contributes to a larger footprint of the MT-ferrule that has a typical height of <NUM>, a length of <NUM>, and a width of <NUM>. Further, molding such ferrules to simply reduce the footprint is challenging with current multi-fiber ferrule designs. Accordingly, at this time, only one MT ferrule in an MPO connector housing footprint meets the space requirements of an SFP/QSFP footprint transceiver interface. Accordingly, Applicant provides a multi-fiber ferrule that allows for a plurality of duplex connector housings to fit in a footprint matching that of a QSFP/SFP footprint transceiver interface, and supporting more than two optical fibers (e.g., <NUM> optical fibers). As a result, two or more of such MT-like ferrules within respective housings can be interfaced with an SFP/QSFP transceiver interface.

In order to use the new higher density fiber optic ferrule, there needs to be a new housing that can receive the new fiber optic ferrule and mate to the transceiver or other assembly.

Multi-fiber ferrules are described in <CIT>, <CIT>, <CIT> and <CIT>.

The present invention is directed to a multi-fiber ferrule as defined by appended claim <NUM>.

In some embodiments, the main body has a thickness and the thickness is less at locations corresponding to the top cut-out and the bottom cut-out than at locations where there are no cut-outs.

In some embodiments, the two side portions are smooth.

In some embodiments, the distance of the top portion is greater than the distance of the bottom portion from the first side portion to the second side portion.

In some embodiments, the top portion has a first surface lying in a first plane and the cut-out has a second surface lying in a second plane, the first and second planes being parallel to but offset from one another, the second plane being closer to an axis extending through the rear central opening between the front end and the rear end.

In some embodiments, the bottom portion has a third surface lying in a third plane and the cut-out has a fourth surface lying in a fourth plane, the third and fourth planes being parallel to but offset from one another, the fourth plane being closer to an axis extending through the rear central opening between the front end and the rear end.

In some embodiments the top cut-out extends rearwardly from the front end to the first forward facing surface; and.

In some embodiments, the top cut-out and the bottom cut-out each divide the respective top portion and the bottom portion into an upper surface and a lower surface without creating an opening into the main body from any of the top portion and the bottom portion of the multi-fiber ferrule.

In some embodiments, each of the upper surfaces and the lower surfaces all lie in a different plane, each of the planes are parallel to one other but off set from one another.

It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention.

Reference will now be made in detail to the present preferred embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

Illustrated in <FIG> is one embodiment of a multi-fiber ferrule <NUM> according to the present invention. The multi-fiber ferrule <NUM> has a main body <NUM> having a top portion <NUM> and a bottom portion <NUM>. There is a first side portion <NUM> that extends between the top portion <NUM> and the bottom portion <NUM>. There is also a second side portion <NUM> extending between the top portion <NUM> and the bottom portion <NUM> on opposites sides of the main body <NUM>. The main body <NUM> also has an end face <NUM> at a front end <NUM> of the main body <NUM> and a rear face <NUM> at a rear end <NUM> of the main body <NUM>. The multi-fiber ferrule <NUM> is significantly smaller than the conventional MT - ferrule and has typical dimensions of <NUM> height, <NUM> length (between the front end <NUM> and the rear end <NUM>), and a width of <NUM> between the first side portion <NUM> and the second side portion <NUM>.

Applicant notes that the term "front" or "forward" means that direction where the fiber optic ferrule would meet with another fiber optic ferrule or device, while the term "rear" or "rearward" is used to mean the direction from which the optical fibers enter into the fiber-optic ferrule or fiber optic connector. In the present application, the multi-fiber ferrule and the fiber optic connector will therefore have a front and a rear, the front will be inserted into an adapter, sleeve or other receptacle. Thus, in <FIG>, the "front" of the multi-fiber ferrule is on the left side of the figure and pointing out of the figure. The "rear" or "back" is that part of multi-fiber ferrule is on the right side of <FIG> and "rearward" and "backward" is toward the right and into the page. The same is true with the fiber optic connector as illustrated in <FIG> - the front is to the left and out, while rear is to the right and back.

As seen in <FIG>, the multi-fiber ferrule <NUM> has a rear central opening <NUM> extending into the main body <NUM> from the rear face <NUM> and configured to receive at least three optical fibers (not shown). The multi-fiber ferrule <NUM> also has a plurality of fiber support structures <NUM> to support the optical fibers. See also <FIG>. The fiber support structures <NUM> are in communication with the rear central opening <NUM> and extending through the main body <NUM> to the end face <NUM>. Along the length of the fiber support structures <NUM> there may be chamfered portions <NUM> that assist in insertion of the optical fibers into the multi-fiber ferrule <NUM> without the skiving of the front ends of the optical fibers. The fiber support structures <NUM> may be fiber openings or fiber bores, but may alternatively be groove structures, or the combination or both. The main body <NUM> may also include two guide pin holes <NUM>, which extend between the end face <NUM> and the rear face <NUM>. The guide pin holes <NUM> provide a reference point with respect to the main body <NUM> and other structures to which the multi-fiber ferrule <NUM> is mated. As noted below, the guide pin holes <NUM> are outside the area of cutouts to allow for enough material in the main body <NUM> to allow for the guide pin holes <NUM>. The end face <NUM> may have a rectangular profile, although a trapezoidal profile (as shown) may also be provided as an alternative.

The top portion <NUM> has a top cut-out <NUM> that forms a first forward facing surface <NUM>. The first forward facing surface <NUM> is used as a stop surface in conjunction with a housing for a connector, e.g., an SFP/QSFP connector. There may also be a number of other surfaces formed by the top cut-out <NUM>. For example there is a second, slanted surface <NUM> on both sides of the top cut-out <NUM> that assist in the location of the multi-fiber ferrule <NUM> in the housing for a connector. The second, slanted surfaces <NUM> assist in moving the multi-fiber ferrule <NUM> in a side-to-side manner relative to the housing. There are also laterally facing surfaces <NUM> on each side that form the last part of the cut-out <NUM> and extend to the end face <NUM> from the second, slanted surfaces <NUM>. As illustrated in the figures, the top cut-out <NUM> does not extend all of the way to the rear end <NUM>, but stops short at the first forward facing surface <NUM>. However, a portion of the top cut-out <NUM> could extend all the way to the back of the multi-fiber ferrule <NUM>. For example, a cutout in the shape of a "T" with a thin narrow section going all the way to the back would work as well, as long as there is at least one forward facing surface adjacent to such a variation of the top cut-out <NUM>. This applies to a bottom cut-out <NUM> as well, described below.

The top portion <NUM> has a first surface <NUM> that lies in a first plane A and the cut-out <NUM> forms a second surface <NUM> that lies in a second plane B. Planes A and B are preferably parallel to one another but off set, with plane B being closer to a longitudinal axis E passing through the center of the main body <NUM> and through the rear central opening <NUM> between the front end <NUM> and the rear end <NUM>. See also <FIG>. It should also be noted that the cut-out portion <NUM> does not extend into the rear central opening <NUM> or the fiber support structures <NUM>.

Similarly, the bottom portion <NUM> has the bottom cut-out <NUM> that forms a second forward facing surface <NUM>. The second forward facing surface <NUM> is also used as a stop surface in conjunction with a housing for a connector. The bottom cut-out <NUM> also has two laterally facing surfaces <NUM> that form a portion thereof. The bottom cut-out <NUM> extends from the end face <NUM> towards the rear end <NUM>, but does not reach the rear end <NUM>. It may reach the same distance toward the rear end <NUM> from the end face <NUM> as does the top cut-out <NUM>, but it may stop short of or beyond where the top cut-out <NUM> stops at forward facing surface <NUM>.

The bottom portion <NUM> has a third surface <NUM> that lies in a third plane C and the bottom cut-out <NUM> forms a fourth surface <NUM> that lies in a fourth plane D. See <FIG> and <FIG>. The Planes C and D are preferably parallel to one another but off set, with plane D being closer to the longitudinal axis E passing through the center of the main body <NUM> and through the rear central opening <NUM> between the front end <NUM> and the rear end <NUM>. It should also be noted that the bottom cut-out <NUM> does not extend into the rear central opening <NUM> or the fiber support structures <NUM>.

It should be noted that the thickness of the main body <NUM> varies across a width and a depth. As seen in <FIG> and <FIG>, the thickness of the main body <NUM> is least where the two cut-outs <NUM>, <NUM> are located. This is seen in <FIG> and represented by the distance between planes B and D. The thickness of the main body <NUM> is greatest where there are no cut-outs, which corresponds to the distance between the planes A and C.

Returning to the main body <NUM>, there is first side portion <NUM> that extends between the top portion <NUM> and the bottom portion <NUM>. There is also a second side portion <NUM> extending between the top portion <NUM> and the bottom portion <NUM> on opposites sides of the main body <NUM>. The first side portion <NUM> and the second side portion <NUM> are smooth between the front end <NUM> and the rear end <NUM>. Additionally, there is no shoulder with multi-fiber ferrule <NUM> making the profile from the back to the front the same as the front to the back - and also the same at the end face <NUM> and the rear face <NUM>. That is, the multi-fiber ferrule <NUM> is shoulder-less. The term shoulder-less referring to a lack of any protrusions or other features on the first side portion <NUM> and the second side portion <NUM> that may be used to engage the multi-fiber ferrule <NUM> with a receptacle or an adapter. There are also no sharp edges along the length of the multi-fiber ferrule <NUM> at the junction of the side portions <NUM>,<NUM> to the top and bottom portions <NUM>,<NUM>. See, e.g., <FIG>. It should also be noted that the top portion <NUM> is wider than the bottom portion. That is, the distance across the top portion <NUM> is greater than the distance across the bottom portion <NUM> between the side portions. That is, W1 is greater that W2 as illustrated in <FIG>. Alternatively, not according to the claimed invention, W1 equals W2.

It should also be noted that the rear surface <NUM> at the rear end <NUM> may also be used as a reference surface for any work that may be done to the multi-fiber ferrule <NUM>. For example, the rear surface <NUM> may be used as a reference surface for polishing the end face <NUM> of the main body <NUM>. The use of the rear surface <NUM> is in addition to the first forward facing surface <NUM> and/or the second forward facing surface <NUM>. Preferably, the wider of the first forward facing surface <NUM> and the second forward facing surface <NUM> would be used as a reference datum surface for polishing and interferometry. The end face <NUM> may be angle-polished (i.e., at an angle relative to the rear face <NUM>). Alternatively, the end-face <NUM> may be flat polished. The top cut-out <NUM> may have a different width than the bottom cut-out <NUM>. This may act as a polarity indication and/or may cause the ferrule to be oriented in a specific direction when received inside a receptacle or an adapter for mating with another ferrule. Alternatively, the top cut-out <NUM> may have a same width as the bottom cut-out <NUM>.

An alternative embodiment of a multi-fiber ferrule <NUM>' is illustrated in <FIG>. In this embodiment, the top portion <NUM>' has two top cut-outs <NUM>' that form two first forward facing surfaces <NUM>'. The two top cut-outs <NUM>' are separated by a continuation 104a' of the top portion <NUM>'. The continuation 104a' of the top portion <NUM>' acts as a key for the a multi-fiber ferrule <NUM>'. This is in addition to the top cut-out <NUM>' having a different width than the bottom cut-out <NUM>'. Thus the continuation 104a' may act as a polarity key or wedge. In an alternative aspect, the continuation 104a' may be presented only partially separate the two top cutouts <NUM>'. Otherwise, the multi-fiber ferrule <NUM>' is the same as noted above with regard to multi-fiber ferrule <NUM>.

Moving to <FIG>, there is one embodiment of a fiber optic ferrule receiver <NUM> to receive a fiber optic ferrule <NUM> according to the present invention. The fiber optic ferrule receiver <NUM> can be used in a number of different connectors and assemblies. As illustrated in <FIG> and <FIG>, the fiber optic ferrule receiver <NUM> is a part of a fiber optic connector <NUM>. Additionally and as discussed in more detail below, the elements of the fiber optic ferrule receiver <NUM> may be found in other receivers as well. For example, the features of the fiber optic ferrule receiver <NUM> may be included in an adapter, into which the fiber optic ferrule <NUM> would be directly inserted.

Now turning to <FIG>, the components of the fiber optic connector <NUM> will be described, moving in a front to rear direction (or left to right in the figure). The fiber optic ferrule receiver <NUM> is on the far left, with the multi-fiber ferrule <NUM> that will be inserted into the fiber optic ferrule receiver <NUM> next in line. While the multi-fiber ferrule <NUM> is illustrated, the invention may apply to other fiber optic ferrules as well. Behind the multi-fiber ferrule <NUM> is a guide pin keeper or spacer <NUM>. A spring <NUM> (or other elastic element) is disposed in front end of a housing <NUM> (and is described in more detail below) to bias the multi-fiber ferrule <NUM> in a forward direction with the fiber optic ferrule receiver <NUM>. A crimp ring <NUM> is used to secure the strength members associated with the optical fibers (not shown) to the housing <NUM>. Finally, a push-pull boot <NUM> is attached to the housing <NUM>.

The fiber optic ferrule receiver <NUM> includes a main body <NUM> extending between a front end <NUM> and a rear end <NUM>. See <FIG> and <FIG>. The main body <NUM> has four sides <NUM>,<NUM>,<NUM>,<NUM>, and an opening <NUM> extending between the front end <NUM> and sides <NUM>,<NUM>,<NUM>,<NUM>. As illustrated, the first side <NUM> and the second side <NUM> are on opposite sides of the opening <NUM>, while the third side <NUM> and the fourth side <NUM> are each connected to the first side <NUM> and the second side <NUM> and are opposite each other about the opening <NUM>. The third side <NUM> and the fourth side <NUM> have internal surfaces that are preferably flat and linear, but they may have tapering features like the internal surfaces of first side <NUM> and second side <NUM>, discussed in detail below. In one aspect of this disclosure, the third side <NUM> may include a polarity step or a polarity mark to indicate orientation of the fiber optic ferrule receiver <NUM> and hence, the fiber optic ferrule <NUM>. See also <FIG>.

The first side <NUM> has a first tapered surface 208a in the opening <NUM> as well as a second tapered surface 208b, the first tapered surface 208a reducing the opening <NUM> between the rear end <NUM> and a first position <NUM>, and the second tapered surface 208b increasing the opening <NUM> between the first position <NUM> and the front end <NUM>. As illustrated in <FIG>, the first tapered surface 208a may have a number of ramped and flat portions. The first tapered surface 208a is to prevent the front end <NUM> of the main body <NUM> of the multi-fiber ferrule <NUM> from encountering any surface that causes damage to the front end <NUM> or causes the multi-fiber ferrule <NUM> from catching as it is inserted into the opening <NUM>.

The second side <NUM> also has a third tapered surface 210a in the opening <NUM> as well as a fourth tapered surface 210b, the third tapered surface 210a reducing the opening <NUM> between the rear end <NUM> and a second position <NUM>, and the fourth tapered surface 210b increasing the opening <NUM> between the second position <NUM> and the front end <NUM>. As can be seen in <FIG>, the first position <NUM> and the second position <NUM> are directly across the opening <NUM> from each other. However, depending on the configuration of the cut-outs in the multi-fiber ferrule, the first position <NUM> and the second position <NUM> may be off set from one another along a longitudinal axis F through the fiber optic ferrule receiver <NUM>. The first portion <NUM> and the second portion <NUM> can be thought of as a line that extends across the opening <NUM> between the third side <NUM> and the fourth side <NUM> and on the first side <NUM> and the second side <NUM>, respectively. Alternatively, the first position <NUM> and/or the second position <NUM> may be a flat surface, e.g., parallel to the first side <NUM> and the second side <NUM>. That is, there may be a flat surface formed at a junction of the first tapered surface 208a and the second tapered surface 208b. Likewise, there may be another flat surface formed at a junction of the third tapered surface 210a and the fourth tapered surface 210b.

The fiber optic ferrule receiver <NUM> has a first projection <NUM> extending into the opening <NUM> from the first side <NUM> to engage the multi-fiber ferrule <NUM> at the first position <NUM>. Preferably the first projection <NUM> engages the first forward facing surface <NUM> of the multi-fiber ferrule <NUM>. However, as noted above, the first projection <NUM> could engage any appropriate structure on the multi-fiber ferrule <NUM>. The projection <NUM> preferably has a rearward facing surface <NUM> to engage the first forward facing surface <NUM> of the multi-fiber ferrule <NUM>. Additionally, the first projection <NUM> extends across the opening <NUM> in the appropriate location and width for that engagement. The first projection <NUM> preferably has a ramp surface <NUM> that extends from the first position <NUM> towards the front end <NUM>. While the ramp surface <NUM> extends all of the way to the front end <NUM>, it could stop short thereof. Alternatively, the first projection <NUM> may have other configurations, such as a flat plateau like profile, instead of a ramp to engage the multi-fiber ferrule <NUM>.

Similarly, the ferrule receiver <NUM> has a second projection <NUM> extending into the opening <NUM> from the second side <NUM> to engage the multi-fiber ferrule <NUM> at the second position <NUM>. Preferably the second projection <NUM> engages the second forward facing surface <NUM> of the multi-fiber ferrule <NUM>. However, as noted above, the second projection <NUM> could engage any appropriate structure on the multi-fiber ferrule <NUM>. The second projection <NUM> preferably has a rearward facing surface <NUM> to engage the second forward facing surface <NUM> of the multi-fiber ferrule <NUM>. Additionally, the second projection <NUM> extends across the opening <NUM> in the appropriate location and width for that engagement with the fiber optic ferrule receiver <NUM>. As is clear in <FIG> (showing the view from the front of the ferrule receiver 200b the first projection <NUM> is not as wide as the second projection <NUM> so that the multi-fiber ferrule <NUM> can only be inserted into the fiber optic ferrule receiver <NUM> in one way. The second projection <NUM> also preferably has a ramp surface <NUM> that extends from the second position <NUM> towards the front end <NUM>. While the ramp surface <NUM> extends all of the way to the front end <NUM>, it could stop short thereof. Alternatively, similar to the first projection <NUM>, the second projection <NUM> may have other configurations, such as a flat plateau like profile, instead of a ramp to engage the multi-fiber ferrule <NUM>.

The configuration of the first projection <NUM> and the second projection <NUM>, particularly with the ramp surfaces <NUM>,<NUM> cause the second and fourth tapered surfaces 208b,210b to be split into two sections - one on each side of the projections <NUM>, <NUM>. At those locations, the first tapered surface 208a and the second tapered surface 208b, as well as the third tapered surface 210a and the fourth tapered surface 210b, are connected to one another about the first position <NUM> and second position <NUM>, respectively. Such a connection, as noted above, may be along a line or along a flat plane.

The rear end <NUM> of the main body <NUM> is not orthogonal to the longitudinal axis F extending through the main body <NUM>. See, e.g., <FIG>. Rather, it has an angle that matches the angle at the front of the housing <NUM>. One will be able to discern from this angled surface, where the first projection <NUM> and the second projection <NUM> are within the main body <NUM>. This will allow for the multi-fiber ferrule <NUM> to be inserted so that the first projection <NUM> and the second projection <NUM> engage correct ones of the forward facing surfaces <NUM>, <NUM> in the multi-fiber ferrule <NUM>. See, e.g., <FIG> and <FIG>.

Extending from the rear end <NUM>, and away from the main body <NUM>, are two tabs <NUM>, one is mounted on side <NUM> and the other on side <NUM>. The two tabs <NUM> each have a shape of the letter "T". The tabs <NUM> have cut-outs <NUM> which form legs <NUM>. The tabs <NUM> and the legs <NUM> are able to flex outward from the opening <NUM> and engage the housing <NUM> as described below. See also <FIG> and <FIG>. The tabs <NUM> have a rear surface <NUM> that is perpendicular to the longitudinal axis F. The cut-outs <NUM> between the tab <NUM> and the legs <NUM> are not rectangular, but are trapezoidal, allowing the rear end <NUM> to be angled, while still having the rear surface <NUM> and the front end <NUM> perpendicular to the longitudinal axis F.

The main body <NUM> of the fiber optic ferrule receiver <NUM> has a plurality of shoulders <NUM> that extending from the front end <NUM> to the rear end <NUM>. The shoulders are generally at the corners of the main body <NUM>, where the sides <NUM>,<NUM>, <NUM>,<NUM> meet. These shoulders <NUM> act as a guide to align the fiber optic connector <NUM> with another receptacle, such as an adapter.

The housing <NUM> will now be described with reference to <FIG>. The housing <NUM> has a main body <NUM> that extends between a front end <NUM> and a rear end <NUM> and generally has three sections. The housing <NUM> also has an opening <NUM> that extends between the front end <NUM> and the rear end <NUM>. The first section <NUM> is a front section that receives an elastic member such as spring <NUM>. As noted above, the elastic member or spring <NUM> is to engage, directly or indirectly, the rear end of the multi-fiber ferrule <NUM> and bias it in a forward direction. The spring <NUM> engages forward facing surfaces <NUM> that extend into the opening <NUM> from the interior surface <NUM> and function as an integral spring stop. Referring to <FIG>, in the cross-section, two of the forward facing surfaces <NUM> are illustrated, each continuing around one side of the housing <NUM> internally (see also <FIG>) on the other half of the main body <NUM> that is not visible. Alternatively, there could preferably be four of the forward facing surfaces <NUM>, two for the half shown in <FIG>, and two more for the half of the housing <NUM> that has been cut in the cross-section of <FIG>. See also <FIG>. The front end <NUM> has a chamfered surface <NUM> that assists in inserting the spring <NUM> during the initial insertion as well as movement of the spring <NUM> during use of the housing <NUM> in the fiber optic connector <NUM>. The opening <NUM> is illustrated as being oval in cross section, but it could have other configurations as needed (e.g., an elliptical configuration). The spring <NUM> is accordingly shaped to be received inside the opening <NUM>, and engage and seat at the forward facing surfaces <NUM>.

Also at the front end <NUM> and on first side <NUM> and on opposing second side <NUM> are depressions <NUM> to receive the tab <NUM> and legs <NUM> from the fiber optic ferrule receiver <NUM> to removably secure the fiber optic ferrule receiver <NUM> to the main body <NUM>. See, <FIG> and <FIG> showing a front view of the housing <NUM>.

The main body <NUM> of the housing <NUM> has a plurality of shoulders <NUM> that extending from the front end <NUM> to the rear end <NUM>. The shoulders are generally at the corners of the main body <NUM>, where first side <NUM> meets with top side <NUM> and bottom side <NUM> and second side <NUM> meets with top side <NUM> and bottom side <NUM>. These shoulders <NUM> act as a guide to align the fiber optic connector <NUM> with another receptacle, such as an adapter. The shoulders <NUM> also match with the shoulders <NUM> on the fiber optic ferrule receiver <NUM> to form a continuous shoulder at each corner.

The second or middle section <NUM> provides an area for the optical fibers <NUM> to transition from a flat ribbon to a grouping that can be protected by a round fiber optic cable covering. Referring to <FIG>, the optical fibers <NUM> extend from the multi-fiber ferrule <NUM> in a flat configuration, the middle section <NUM> allows for them to be grouped together to pass out the rear end <NUM> in circular configuration and in a cable sheath <NUM>. As is known in the art, the optical fibers <NUM> cannot be bent beyond their bend radius without damaging the optical fibers <NUM>. This transition area <NUM> assists in preventing such damage. The transition area <NUM> is dimensioned to maintain a safe bend radius for the individual optical fibers <NUM> as these optical fibers <NUM> transition from a ribbon form to a fiber optic cable form with loose fibers therein.

The third or rear section <NUM> is used to finalize the configuration of the optical fibers <NUM> from the transition area in the middle section <NUM> to the cable format. The rear section <NUM> has an outer surface <NUM> to engage the crimp ring <NUM>. The outer surface <NUM> is on a circular extension or crimp body <NUM> that extends from the rear end <NUM>. Additionally, the crimp body <NUM> is preferably made from two portions, a first portion <NUM> that is integral with the main body <NUM> and a second portion <NUM> that is removable from the main body <NUM> and the first portion <NUM>. See <FIG> and <FIG>. The second portion <NUM> has a rear section <NUM> that is a half cylinder and a forward section <NUM> that mates with the main body <NUM> to close the middle section <NUM>. The rear portion <NUM> mates with the first portion <NUM> to form the cylindrical shape that can accept the crimp ring <NUM>. The rear section <NUM> mates with the first portion <NUM> with a series of projections <NUM> and recesses <NUM>. As illustrated in the figures, the projections <NUM> are on the first portion <NUM> and the recesses <NUM> are on the second portion <NUM>. However, the projections and recesses could be reversed or mixed with regard to their positions on the first portion <NUM> and the second portion <NUM>. The projections <NUM> preferably frictionally engage the recesses <NUM> and then once the crimp ring <NUM> is secured around the crimp body <NUM>, the two portions <NUM>,<NUM> will not move relative to one another.

The forward section <NUM> of the second portion <NUM> mates with the main body <NUM> of the housing <NUM>. The main body <NUM> has an extra portion <NUM> that has been cut out to allow for more optical fibers and larger groups of optical fibers to pass through the opening <NUM>. This makes the opening <NUM> at the forward section <NUM> larger than on the opposing side. The larger opening <NUM> allows the housing <NUM> to be installed onto the cable and slid down the cable and out of the way during termination and polishing of the ferrule <NUM>. That is when viewed straight into the opening <NUM> from the rear section <NUM>, or even from the front end <NUM>, the opening <NUM> is asymmetrical due to the presence of the first portion <NUM> and the extra portion <NUM>. See <FIG>, <FIG>. The forward section <NUM> of the crimp body <NUM> has a tab <NUM> that extends into the extra portion <NUM> to close it off when the two portions <NUM>,<NUM> are mated.

The housing <NUM> also has a number of latches <NUM> that extend from the main body <NUM> to engage a push-pull boot <NUM> and more specifically two latches <NUM> on the push-pull boot. See <FIG>, <FIG>, <FIG>, and <FIG>. As illustrated, the latches <NUM> on the push-pull boot can slide in the area <NUM> between two latches <NUM> on each side of the housing <NUM>. When the push-pull boot <NUM> is pulled, the latches <NUM> slide within the area <NUM> until they reach the end of the latches <NUM> and at this point, the force is transferred to the latches <NUM> and the housing <NUM> to remove the fiber optic connector from its receiver. To insert the fiber optic connector <NUM>, the push-pull boot <NUM> is pushed until the latches <NUM> engage the front end of the area <NUM>, which then transfers to the housing <NUM> and moves the fiber optic connector in a forward direction to secure it within a receptacle.

It is also possible, as an alternative to this configuration, whereby at least one of the latches is molded on the second portion. Referring to <FIG>, there is a housing 406a that has a second portion 492a of a crimp body 486a and a latch 520a molded thereon. The housing 406a has the same components as the housing discussed above, as well as the extra portion <NUM>' that has been cut out to allow for more optical fibers and larger groups of optical fibers to be used with this housing 406a.

Another embodiment of a housing <NUM>' and a fiber optic ferrule receiver <NUM>' according to the present invention are illustrated in <FIG>. First, it should be noted that the fiber optic ferrule that is used in these figures corresponds to multi-fiber ferrule <NUM> discussed above, but another fiber optic ferrule could also be used.

This embodiment of a fiber optic ferrule receiver <NUM>' includes a main body <NUM>' extending between a front end <NUM>' and a rear end <NUM>'. As in the prior embodiment, the main body <NUM>' also has four sides <NUM>',<NUM>',<NUM>',<NUM>', and an opening <NUM>' extending between the front end <NUM>' and the rear end <NUM>' and being defined at least by a portion of internal surfaces of the four sides <NUM>',<NUM>',<NUM>',<NUM>'. The fiber optic ferrule receiver <NUM>' also includes two tabs <NUM>' that extend rearwardly from the rear end <NUM>'. The two tabs <NUM>' each have a projection <NUM>' that extend outwardly and away from each other. The projections <NUM>' are designed to engage an opening <NUM>' on each side of the housing <NUM>', as described in more detail below. The two tabs <NUM>' are somewhat flexible in that they can flex inward to be inserted into the housing <NUM>' and subsequently return, at least partially, to their pre-flexed configuration. This allows the fiber optic ferrule receiver <NUM>' to be retained in the housing <NUM>'.

Turning to <FIG>, the length of fiber optic ferrule receiver <NUM>' (the distance between the front end <NUM>' and the rear end <NUM>') is shorter than that of fiber optic ferrule receiver <NUM>. The housing <NUM>' is therefore longer so that the combination of the housing <NUM>' and the fiber optic ferrule receiver <NUM>' are preferably the same overall length. It is also clear from <FIG> that the rear end <NUM>' of the a fiber optic ferrule receiver <NUM>' and the front end of the housing <NUM>' are slanted as in the previous embodiment for the purposes of polarity.

The opening <NUM>' of the fiber optic ferrule receiver <NUM>' has the same general configuration of a fiber optic ferrule receiver <NUM>. That is, first side <NUM>' and second side <NUM>' are on opposite sides of the opening <NUM>', while third side <NUM>' and fourth side <NUM>' are each connected to the first side <NUM>' and the second side <NUM>' and are opposite each other about the opening <NUM>'. Third side <NUM>' and fourth side <NUM>' have internal surfaces that are preferably flat and linear, but they may have tapering features discussed above.

First side <NUM>' has a first tapered surface 208a' in the opening <NUM>' as well as a second tapered surface 208b', the first tapered surface 208a' reducing the opening <NUM>' between the rear end <NUM>' and a first position <NUM>', and the second tapered surface 208b' increasing the opening <NUM>' between the first position <NUM>' and the front end <NUM>'. The first tapered surface 208a' may have a number of ramped and flat portions. The first tapered surface 208a' is to prevent the front end <NUM> of the main body <NUM> of the multi-fiber ferrule <NUM> from encountering any surface that causes damage to the front end <NUM> or causes the multi-fiber ferrule <NUM> from catching as it is inserted into the opening <NUM>.

Second side <NUM>' also has a third tapered surface 210a' in the opening <NUM>' as well as a fourth tapered surface 210b', the third tapered surface 210a' reducing the opening <NUM>' between the rear end <NUM>' and a second position <NUM>', and the fourth tapered surface 210b' increasing the opening <NUM>' between the second position <NUM>' and the front end <NUM>'. As can be seen in <FIG>, the first position <NUM>' and the second position <NUM>' are directly across the opening <NUM>' from each other. However, depending on the configuration of the cut-outs in the multi-fiber ferrule <NUM>, the first position <NUM>' and the second position <NUM>' may be off set from one another. The first portion <NUM>' and the second portion <NUM>' can be thought of as a line (that may have a number of thicknesses) that extends across the opening <NUM>' between the third side <NUM>' and the fourth side <NUM>' and on the first side <NUM>' and the second side <NUM>', respectively. However, as described with respect to the embodiments above, the first portion <NUM>' and the second portion <NUM>' can also be a plane rather than a line.

As with the prior embodiment, the fiber optic ferrule receiver <NUM>' has a first projection <NUM>' extending into the opening <NUM>' from the first side <NUM>' to engage the multi-fiber ferrule <NUM> at the first position <NUM>'. Preferably the first projection <NUM>' engages the first forward facing surface <NUM> of the multi-fiber ferrule <NUM>. The ferrule receiver <NUM>' has a second projection <NUM>' extending into the opening <NUM>' from the second side <NUM>' to engage the multi-fiber ferrule <NUM>' at the second position <NUM>'. Preferably the second projection <NUM>' engages the second forward facing surface <NUM> of the multi-fiber ferrule <NUM>.

Turning to <FIG>, the other embodiment of the housing <NUM>' will be explained. The housing <NUM>' has a main body <NUM>' that extends between a front end <NUM>' and a rear end <NUM>' and generally has three sections. The first section <NUM>' is a front section that receives an elastic member such as spring <NUM>. The second or middle section <NUM>' provides an area for the optical fibers <NUM> to transition from a flat ribbon to a grouping that can be protected by a round fiber optic cable covering. The third or rear section <NUM>' is used to finalize the configuration of the optical fibers from the transition area in the middle section <NUM>' to the cable format. Except for the first section <NUM>', the other sections are the same as discussed above and will not be repeated here.

The housing <NUM>' also has an opening <NUM>' that extends between the front end <NUM>' and the rear end <NUM>'. The first section <NUM>' receives an elastic member such as spring <NUM>. As noted above, the elastic member or spring <NUM> is to engage, directly or indirectly, the rear end of the multi-fiber ferrule <NUM> and bias it in a forward direction. The spring <NUM> engages forward facing surfaces <NUM>' that extend into the opening <NUM>' from the interior surface <NUM>' and function as an integral spring stop. Referring to <FIG>, two of the forward facing surfaces <NUM>' are illustrated. The front end <NUM>' has a chamfered surface <NUM>' that assists in inserting the spring <NUM> during the initial insertion as well as movement of the spring <NUM> during use of the housing <NUM>' in a fiber optic connector <NUM>. The opening <NUM>' is illustrated as being oval in cross section, but it could have other configurations as needed.

The main body <NUM>' of the housing <NUM>' has a plurality of shoulders <NUM>' that extending from the front end <NUM>' to the rear end <NUM>'. The shoulders are generally at the corners of the main body <NUM>', where first side <NUM>' meets with top side <NUM>' and bottom side <NUM>' and second side <NUM>' meets with top side <NUM>' and bottom side <NUM>'. These shoulders <NUM>' act as a guide to align the fiber optic connector <NUM> with another receptacle, such as an adapter. The shoulders <NUM>' also match with the shoulders on the both of the embodiments of fiber optic ferrule receiver to form a continuous shoulder at each corner.

At the front end <NUM>' of the main body <NUM>' and on both first side <NUM>' and second side <NUM>' is a depression <NUM>' that also has the opening <NUM>' to receive the projections <NUM>' from the tabs <NUM>' when the fiber optic ferrule receiver <NUM>' is inserted into the opening <NUM>'. There are also two pockets <NUM>' that are closest to the top side <NUM>' and bottom side <NUM>' to receive a part of the ferrule and/or the guide pin keeper or spacer <NUM>. See <FIG> and <FIG>.

Illustrated in <FIG> is an embodiment of a combination of a housing and a fiber optic ferrule receiver according to the present invention. The housing <NUM> has a front section <NUM> that incorporates the features of the fiber optic ferrule receiver <NUM>,<NUM>' above. The housing <NUM> has a front end <NUM> and a rear end <NUM> with an opening <NUM> extending therebetween. The housing <NUM> has a rear section <NUM> that receives the spring <NUM> from the rear end <NUM>. As with other housings, the spring <NUM> engages the back of the multi-fiber ferrule <NUM>, either directly or indirectly to bias it to the front of the housing <NUM>.

The front section <NUM> has a first side <NUM> that has a first tapered surface 612a in the opening <NUM> as well as a second tapered surface 612b. As with the prior embodiments, the first tapered surface 612a reduces the opening <NUM> between the rear end <NUM> and a first position <NUM>, and the second tapered surface 612b increasing the opening <NUM> between the first position <NUM> and the front end <NUM>.

The front section <NUM> has a second side <NUM> that has a third tapered surface 616a in the opening <NUM> as well as a fourth tapered surface 616b. As with the prior embodiments, the third tapered surface 616a reduces the opening <NUM> between the rear the rear end <NUM> and being defined at least by a portion of internal surfaces of the four end <NUM> and a second position <NUM>, and the fourth tapered surface 616b increasing the opening <NUM> between the second position <NUM>. and the front end <NUM>.

The front section <NUM> also includes a first projection <NUM> that extends into the opening <NUM> from the first side <NUM> to engage the multi-fiber ferrule <NUM> at the first position <NUM>. It also includes a second projection <NUM> that extends into the opening <NUM> from the second side <NUM> to engage the multi-fiber ferrule <NUM> at the second position <NUM>. Thus, the elements of the fiber optic ferrule receiver have been incorporated into the housing and could, by extension, be added to other structures as well.

Claim 1:
A multi-fiber ferrule (<NUM>, <NUM>') comprising:
a main body (<NUM>) having a top portion (<NUM>, <NUM>') and a bottom portion (<NUM>, <NUM>'), a first side portion (<NUM>) extending between the top portion and the bottom portion and a second side portion (<NUM>) extending between the top portion and the bottom portion on opposites sides of the main body, an end face (<NUM>) at a front end (<NUM>) of the main body, and a rear face (<NUM>) at a rear end (<NUM>) of the main body;
a rear central opening (<NUM>) extending into the main body from the rear end face and configured to receive at least three optical fibers (<NUM>);
the top portion having a top cut-out (<NUM>, <NUM>') therein to form a first forward facing surface (<NUM>, <NUM>') to engage a housing of a fiber optic connector, the top cut-out extending rearwardly from the front end; and
the bottom portion also having a bottom cut-out (<NUM>, <NUM>') therein to form a second forward facing surface (<NUM>, <NUM>') to engage the housing of the fiber optic connector, the bottom cut-out also extending rearwardly from the front end,
characterized in that the top portion (<NUM>) is wider than the bottom portion (<NUM>), that is, a distance (W1) across the top portion (<NUM>) from the first side portion (<NUM>) to the second side portion (<NUM>) is greater than a distance (W2) across the bottom portion (<NUM>) from the first side portion (<NUM>) to the second side portion (<NUM>)
wherein the multi-fiber ferrule (<NUM>, <NUM>') is shoulderless, wherein shoulderless is referring to a lack of any protrusions or other features on the first side portion (<NUM>) and the second side portion (<NUM>) that may be used to engage the multi-fiber ferrule (<NUM>) with a receptacle or an adapter.