MPO connector with non-MT multi-fiber optical fiber ferrule and sleeve therefor

Abstract

A fiber optic connector for a fiber optic ferrule has an outer housing, an inner housing at least partially disposed within the outer housing, an inner sleeve positioned within the inner housing and engageable with a rearward facing surface within the inner housing, a ferrule engaged by a rearward facing surface of the inner sleeve, and a spring, the spring is located rearward of the rear end of the inner sleeve and exerts a force on the rear end of the inner sleeve to bias the ferrule and the inner sleeve in a forward direction, where the combination of the inner sleeve and the ferrule is in a floating configuration within the connector.

Description

[0001] References to related cases

[0002] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 63 / 390,953 filed on July 20, 2022 and U.S. Provisional Application No. 63 / 393,739 filed on July 29, 2022, the contents of which are hereby incorporated by reference in their entirety. Background of the Invention

[0004] Conventional MPO fiber optic connectors support standard MT multi-fiber fiber optic ferrules in an inner housing. One such MPO connector is the applicant's PRO brand connector. The MPO connector also has an outer shell or outer sleeve to assist in removal from and insertion into the adapter or receptacle. Sometimes, the combination of the inner shell and the outer sleeve is also simply referred to in the industry as a "shell" or "MPO shell". As is known to those of ordinary skill in the art, a conventional MPO connector shell can only support an MT ferrule having at least three optical fibers (typically 8-16 fibers) terminated therein as a row of optical fibers, although two or more rows are also available. The individual fibers in the MT ferrule are typically separated by a spacing of 250 μm at the end face of the MT ferrule.

[0005] Recent advances in data center technology have driven the need for higher density optical interconnects. To address this challenge, the applicant has introduced what the industry now knows as a TMT fiber ferrule. The newer TMT ferrule is a significantly smaller multi-fiber ferrule than a standard MT ferrule. Figure 1 and Figure 2 Examples of the relative dimensions of two multi-fiber ferrules, MT 10 and TMT 20, are shown respectively. Typical dimensions for the larger MT ferrule are 3.0 mm height, 8.05 mm length between the front and rear ends, and 7 mm width. In contrast, the dimensions for the TMT ferrule are 1.25 mm height, 4 mm length (between the front and rear ends), and 6.4 mm width. That is, the TMT ferrule has a much smaller footprint than the MT ferrule. More details about the TMT ferrule are provided in the applicant's international patent application number PCT / US2021 / 028919 entitled "Miniature Multi-Fiber Ferrule" (publication number WO 2021 / 217050, hereinafter referred to as "the '050 disclosure", and the international patent application is incorporated herein by reference). An example difference between a TMT ferrule and a MT ferrule is that there are no protruding shoulders in the TMT ferrule. Instead, the TMT ferrule has cutouts 22, 24 in the body of the ferrule. See again Figure 2The spacing between the optical fibers in the TMT ferrule is still 250 μm for backward compatibility. The applicant also disclosed an example non-MPO connector housing for seating the TMT ferrule in the '050 publication (see, for example, the '050 publication). Figure 8 ). The optical interconnect industry is beginning to observe a shift toward using TMT ferrules instead of MT ferrules for a variety of reasons, with the smaller size of the TMT ferrule being a major reason.

[0006] There are also some other types of smaller MT-type ferrules available on the market. One such smaller ferrule is being marketed by Senko Advanced Components of Massachusetts. This smaller ferrule is designed for use with the -MT brand connector. Similarly, FSG Networks Limited of Japan offers a smaller MT-like ferrule. Each of these types of multi-fiber ferrules includes an internal fiber support structure (as does the new TMT ferrule) to secure the fibers for termination therein. Although these two smaller ferrules look like smaller versions of the standard MT ferrule, no conventional MPO connector can accommodate these two additional non-standard MT-like ferrules.

[0007] As the shift to smaller amounts of space is occurring, there is also a need to use TMT ferrules to mate with MT ferrules and / or MPO connectors with MT ferrules. In addition, the applicant has also found a need to use TMT ferrules in older MPO housings that are currently unable to support TMT ferrules by themselves.

[0008] In still another field application, MT ferrules are used in pre-filled adapter assemblies with MPO housings. In these applications, a terminated MT ferrule with a fiber ribbon is provided with a ferrule pusher within a pulling grip of a cable bundle. The terminated MT ferrule along with the ferrule pusher is pulled out of the pulling grip at the edge of a data center, and the ferrule pusher is used to simply push the terminated MT ferrule into an adapter pre-filled with an MPO housing. This scenario is described, for example, in U.S. Patent No. 11,280,966 of the present applicant (hereinafter referred to as the "'966 patent", and the entire contents of the U.S. patent are incorporated herein by reference).

[0009] Likewise, as adoption of TMT ferrules continues to increase, in the scenario described in the '966 patent, the present applicants have discovered that the MT ferrule can be replaced with a TMT ferrule without making any changes to the currently used ferrule pushers.

[0010] The applicant has therefore provided a way to use a TMT ferrule in an MPO housing without requiring extensive modification of the MPO housing. Summary of the invention

[0011] According to one aspect, the present invention relates to a multi-fiber optical fiber connector for a multi-fiber optical fiber ferrule, the multi-fiber optical fiber ferrule having at least one row of terminated optical fibers, the multi-fiber optical fiber connector comprising: an outer shell; an inner shell at least partially disposed within the outer shell; an inner sleeve having a main body and a shoulder at a rear portion of the main body, the inner sleeve being at least partially positioned within the inner shell and engageable with a rearward-facing surface within the inner shell and having a central opening, the multi-fiber optical fiber ferrule having a fiber support structure for retaining the optical fibers in the at least one row of terminated optical fibers, the multi-fiber optical fiber ferrule being engaged by the rearward-facing surface of the inner sleeve; and a spring positioned behind the rear end of the inner sleeve and applying a force to the rear end of the inner sleeve to bias the multi-fiber optical fiber ferrule and the inner sleeve in a forward direction, wherein the combination of the inner sleeve and the multi-fiber optical fiber ferrule is in a floating configuration within the multi-fiber optical fiber connector.

[0012] In some embodiments, the multi-fiber optical fiber connector is an MPO connector, and the multi-fiber optical fiber ferrule is a TMT ferrule.

[0013] In some embodiments, a sleeve shoulder may be formed on the main body, the sleeve shoulder being used to engage with an inner housing of a multi-fiber optical fiber connector.

[0014] In some embodiments, at least one centering element may be provided to support a spring for biasing the sleeve in a forward direction toward the multi-fiber fiber optic stub.

[0015] In some embodiments, a sleeve slot may be formed on one side of the body, the sleeve slot extending longitudinally between the rear portion and the middle portion to allow the at least one terminated optical fiber ribbon to be inserted into the central opening.

[0016] In some embodiments, a top extension and a bottom extension may also be provided in the front portion of the main body, and the top extension and the bottom extension extend away from both the middle portion and the rear portion, each of the top extension and the bottom extension having a rearward-facing surface at a free end for engaging a multi-fiber optical fiber ferrule.

[0017] In another aspect, the present invention relates to a sleeve for receiving a multi-fiber optical fiber ferrule, the sleeve comprising: a main body having a front portion, a middle portion and a rear portion; a top extension and a bottom extension in the front portion and extending away from both the middle portion and the rear portion, each of the top extension and the bottom extension having a rearward-facing surface at a free end for engaging the multi-fiber optical fiber ferrule; a central opening extending longitudinally between the rear end of the rear portion and the front end of the middle portion and communicating with the space between the top extension and the bottom extension, the central opening being configured to receive at least two optical fibers; a pair of guide pin holes extending longitudinally on opposite sides of the central opening and also between the rear end of the rear portion to the front end of the middle portion; a sleeve shoulder formed on the main body, the sleeve shoulder being used to engage the inner housing of the multi-fiber optical fiber connector; and wherein the middle portion includes at least one ferrule seat adjacent to the central opening between the top extension and the bottom extension, the ferrule seat being used to seat the multi-fiber optical fiber ferrule.

[0018] In some embodiments, at least one centering element may be further provided to support a spring for biasing the sleeve toward the multi-fiber fiber ferrule in a forward direction.

[0019] In some embodiments, a sleeve groove may also be formed on one side of the body, the sleeve groove extending longitudinally between the rear portion and the middle portion to allow at least two optical fibers to be inserted into the central opening.

[0020] In some embodiments, the main body has at least one receptacle at the rear end of the rear portion, the receptacle being configured to receive at least one protrusion from a pin fixture disposed at the rear of the multi-fiber optical fiber ferrule.

[0021] It will be understood that both the above general description and the following detailed description of the current embodiments of the invention are intended to provide an overview or framework for understanding the nature and features of the claimed invention. 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 accompanying drawings illustrate different embodiments of the invention and together with the description serve to explain the principles and operation of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a front perspective view of an MT ferrule;

[0023] Figure 2 This is the front stereogram of the TMT ferrule;

[0024] Figure 3 is a perspective view of an embodiment of an MPO connector with an inner sleeve according to the present invention;

[0025] Figure 4 yes Figure 3A perspective view of an MPO connector in which the inner housing is cut away to reveal an embodiment of an inner sleeve according to the present invention;

[0026] Figure 5 yes Figure 3 A perspective view of a cross section of an MPO connector;

[0027] Figure 6 yes Figure 3 A perspective view of the internal components of the MPO connector in FIG. 1 , wherein the inner and outer housings are removed, showing the TMT ferrule, sleeve, pin fixture, and optical fiber in ribbon form;

[0028] Figure 7 yes Figure 6 A bottom perspective view of the internal components of the MPO connector;

[0029] Figure 8 yes Figure 6 A top rear perspective view of the internal components of the MPO connector;

[0030] Fig. 9 yes Figure 6 A perspective view of the internal components of the MPO connector in FIG. 1 , wherein the inner sleeve is in section;

[0031] Fig.10 yes Fig. 9 A front perspective view of the inner sleeve in FIG.

[0032] Fig.11 yes Fig. 9 A three-dimensional view of the inner sleeve in FIG.

[0033] Fig.12 yes Fig. 9 A rear elevation view of the inner sleeve in FIG.

[0034] Fig.13 is a rear perspective view of another embodiment of an inner sleeve according to the present invention;

[0035] Fig.14 is a front perspective view of another embodiment of an inner sleeve according to the present invention;

[0036] Fig.15 is a perspective view of another embodiment of a two-piece inner sleeve, a ferrule, a pin fixture and an optical fiber according to the present invention;

[0037] Fig.16 yes Fig.15 An exploded view of the two-piece inner sleeve in;

[0038] Fig.17 is a front perspective view of an inner housing of an MPO connector having a protrusion on an inner surface;

[0039] Fig.18 yes Fig.17 A perspective view of a cross section of an inner housing and other parts of an MPO connector;

[0040] Fig.19 is from Fig.18 A top perspective view of an MPO connector, wherein the inner housing is in section;

[0041] Fig. 20 is a front perspective view of another embodiment of an MPO connector according to the present invention and a different ferrule with an inner sleeve;

[0042] Fig.21 yes Fig. 20 An exploded view of the MPO connector in FIG. 1 , with the spring removed for clarity;

[0043] Fig. 22 yes Fig. 20 A perspective view of a cross section of an MPO connector;

[0044] Fig.23 is from Fig. 20 A perspective view of a cross section of an MPO connector observed from the top;

[0045] Fig.24 yes Fig. 20 A perspective view of the internal components of an MPO connector;

[0046] Fig.25 yes Fig. 20 A front perspective view of the sleeve in FIG. 1 ; and

[0047] Fig.26 yes Fig.25 A three-dimensional view of a cross section of a sleeve. DETAILED DESCRIPTION

[0048] Reference will now be made in detail to the present preferred embodiments of the present 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.

[0049] Figure 3-5A multi-fiber optical fiber connector 100 (connector) is illustrated, which has at least one terminated optical fiber ribbon 102 and an outer shell 104, an inner shell 106 at least partially disposed within the outer shell 104, an inner sleeve 108 (also interchangeably referred to as "sleeve 108"), and a multi-fiber optical fiber ferrule 20 (ferrule 20). Again, the ferrule 20 is smaller than the standard MT 10. The optical fibers that make up the optical fiber ribbon 102 are terminated within the ferrule 20, as is known in the art. A person of ordinary skill in the art will understand after reading this disclosure that although the optical fiber ribbon 102 is shown, bundled loose fibers may also be provided alternatively (i.e., in a non-bonded arrangement structure). The ferrule 20 has a support structure 28 for holding the optical fibers of at least one terminated optical fiber ribbon 102. The ferrule 20 then has at least one row of terminated optical fibers, whether the optical fiber ribbon 20 is used or loose fibers are used. In one embodiment, the support structure 28 may be a microhole or a v-shaped channel. Other configurations may also be provided to support the optical fibers that make up the optical fiber ribbon 102. As shown herein, the connector 100 is an MPO connector and the ferrule is a TMT ferrule, but the principles disclosed herein may also be applicable to other multi-fiber fiber connectors and multi-fiber fiber ferrules that are smaller than the standard MT 10. A spring 110 may also be provided, which is positioned behind the rear end of the inner sleeve 108 and applies a force to the rear end of the inner sleeve to bias the multi-fiber fiber ferrule 20 and the inner sleeve 108 in a forward direction. The ferrule 20 may also have a guide pin 112 to assist in the mating of multiple connectors 100. Figure 6-9 The connector 100 is illustrated with the outer housing 104 and the inner housing 106 removed for clarity. Figure 10-13 One embodiment of the inner sleeve 108 itself according to the present invention is shown.

[0050] Applicants note that the terms "front" or "forward" as used herein refer to the direction in which the connector 100 will meet another connector or device or mating ferrule in a receptacle, while the terms "rear" or "rearward" are used to refer to the direction from which the optical fiber enters the ferrule 20 or connector 100. Each of the components will therefore have a front and a rear, and two corresponding front or forward portions of, for example, opposing ferrules will engage with each other. Thus, for example, in Figure 3 In the embodiment of the present invention, the "front" of connector 100 is on the left, and "forward" is to the left and out of the page. "Backward" or "rear" is the part of connector 100 on the right side of the page, and "backward" and "towards" are toward the right and into the page.

[0051] The inner sleeve 108 has a body 120 and a shoulder 122 at a rear portion 124 of the body 120. Figure 10-12The body 120 also has a front portion 126 and a middle portion 128. The middle portion 128 is thus disposed between the front portion 126 and the rear portion 124. The body 120 has a sleeve shoulder 130 between the middle portion 128 and the rear portion 124 for engaging the inner housing 106, as described in detail below with reference to Figure 5 The body 120 has a central opening 132 that extends longitudinally from at least the rear portion 124 to the middle portion 128. The front portion 126 has two extensions extending from the middle portion 128 and away from the rear portion 124, namely a top extension 140 and a bottom extension 142. An opening 144 is formed between the top extension 140 and the bottom extension 142, and is connected to the central opening 132 and can even be regarded as a part of the central opening. Protrusions 150, 152 for engaging the ferrule 20 are provided at the distal free ends 146, 148 of the top extension 140 and the bottom extension 142. The protrusion 150 preferably has a ramp surface 150a, and the protrusion 152 has a ramp surface 152a, and each of the ramp surfaces is generally away from the middle portion 128. When inserting the ferrule 20 into the inner sleeve 108, the ramp surface 150a and the ramp surface 152a assist by causing the top extension 140 and the bottom extension 142 to flex away from each other and allow the ferrule 20 to enter between the top extension and the bottom extension. The top extension 140 and the bottom extension 142 also preferably include rearward facing surfaces 150b, 152b, respectively. The rearward facing surface 150b and the rearward facing surface 152b engage the forward facing surface 26 on the ferrule 20 to assist in retaining the ferrule 20 within the connector 100. See also Figure 2 and Figure 5 .

[0052] The inner sleeve 108 preferably includes at least one ferrule seat 160 disposed in the middle portion 128 of the body 120. Figure 4 , Figure 6 and Fig.10 , wherein a ferrule seat 160 is provided on both the upper and lower sides of the body 120 (through the top extension 140 and the bottom extension 142). Therefore, the ferrule seat 160 is adjacent to the central opening 132 and is located on opposite sides of the central opening.

[0053] The inner sleeve 108 preferably includes at least one centering element, and in this embodiment, two centering elements are provided: an upper centering element 170 and a lower centering element 172. The centering elements 170, 172 are preferably attached to the rear portion 124 on opposite sides of the central opening 132 and extend rearwardly away from the body 120. The centering elements 170, 172 can be identical to one another, or as illustrated in the figures, one can be different from the other - length, width, etc. In this case, the lower centering element 172 is longer than the upper centering element 170, so that the lower centering element extends beyond the pin clamp 180 (see, e.g., Figure 4 and Figure 7 ). The centering elements 170, 172 are used to center the spring 110 on the pin fixture 180 so that an even pressure is provided to the pin fixture 180 and then to the ferrule 20. However, if there is no pin fixture 180, the upper centering element 170 can also be omitted, but it is beneficial. Other configurations of the centering elements 170, 172 are also optional (for example, rib structures or skeleton structures).

[0054] The inner sleeve 108 may also include guide pin holes 190, 192 in the rear portion 124 that allow the guide pin 112 to be inserted therethrough and into the pin clamp 180. The inner sleeve 108 may also have dimples 194, 196 on the rear surface of the rear portion 124 that receive protrusions on the pin clamp 180 to better secure the pin clamp 180 to the inner sleeve 108. However, these may also be omitted, particularly where the pin clamp 180 is not used.

[0055] The inner sleeve 108 also includes a sleeve slot 200 that provides access from outside the inner sleeve 108 to the central opening 132. The sleeve slot 200 is shown adjacent to a top corner of the inner sleeve 108, which allows the optical fibers of the optical fiber ribbon 102 to be inserted into the central opening 132. The sleeve slot 200 may also be located at other locations on the body 120 and take different shapes. The sleeve slot 200 causes the top extension 140 to be asymmetrical, unlike the bottom extension 142. The sleeve slot 200 may also be located elsewhere if so desired so as not to interfere with the extensions 140, 142. It should be noted that the sleeve slot 200 may also interfere with at least a portion of one of the recesses 194, 196 on the rear surface of the rear portion 124. See, e.g. Fig.11 and Fig.12 Another potential conflict is with the sleeve groove 200 and a portion of the upper centering element 170. The upper centering element 170 may have to be reduced to avoid interference - see Fig.12 The location of the dimples 194, 196 or protrusions on the pin fixture 180 may also be repositioned to allow all of these features to be present simultaneously.

[0056] Return to Figure 5, the inner sleeve 108 is at least partially positioned within the inner housing 106, and the sleeve shoulder 130 (facing forward in the connector 100) can engage with a rearwardly facing surface 134 within the inner housing 106. Figure 5 As is also clear from the connector 100, the spring 110 is positioned behind the rear end of the inner sleeve 108 and applies a force to the rear end of the inner sleeve to bias the ferrule 20 and the inner sleeve 108 in a forward direction. When a pin fixture 180 is present in the connector 100, the force from the spring 110 is applied to the rear end of the inner sleeve 108 through the pin fixture 180 to bias the ferrule 20. With the spring 110 and the inner sleeve 108 so positioned, the combination of the inner sleeve 108 and the ferrule 20 is in a floating configuration within the connector 100. The term "floating" as used herein refers to the ferrule 20 and the inner sleeve 108 engaging the inner housing 106 only at the forward facing surface 130 of the shoulder 122. The rearward facing surface at the rear portion 124 thus has the same amount of enclosed area or space as the standard MT 10, making the combination of the ferrule 20 and the inner sleeve 108 compatible with standard MPO housings. This also allows the use of the standard ferrule pusher of the standard MT 10 to be used with the ferrule 20 and sleeve 108 combination within a pull mesh sleeve for insertion into a pre-filled adapter with an MPO housing attached.

[0057] Another embodiment of the inner sleeve 208 according to the present invention is Fig.13 In this embodiment, there is no sleeve groove in the body 220 because the optical fibers of the optical fiber ribbon 102 can be inserted into the inner sleeve 208, and the inner sleeve 208 can be inserted into a connector with a ferrule 20 (connector 100 or other connectors as discussed above). The rest of the components are the same as when there is an inner sleeve 108. For completeness, the following elements are Fig.13 , and some of the elements discussed above are still present even though they are not visible - except for the sleeve groove.

[0058] The inner sleeve 208 has a body 220 and a shoulder 222 at a rear portion 224 of the body 220. The body 220 also has a front portion 226 and a middle portion 228. The middle portion 228 is thus disposed between the front portion 226 and the rear portion 224. The body 220 has a sleeve shoulder 230 between the middle portion 228 and the rear portion 224 for engaging the rearwardly facing surface 134 of the inner housing 106. The body 220 has a central opening 232 extending longitudinally from at least the rear portion 224 to the middle portion 228. The front portion 226 has two extensions extending from the middle portion 228 and away from the rear portion 224, namely a top extension 240 and a bottom extension 242. An opening 244 is formed between the top extension 240 and the bottom extension 242 and is in communication with the central opening 232 and may even be considered a part of the central opening. Protrusions are provided at the distal free ends 246, 248 of the top extension 240 and the bottom extension 242 to engage the ferrule 20. The protrusions have ramped surfaces, and each ramped surface generally faces away from the middle portion 228. The top extension 240 and the bottom extension 242 also preferably include a rearward-facing surface (not shown), respectively. The rearward-facing surface engages the forward-facing surface 26 on the ferrule 20, as in the previous embodiment.

[0059] The inner sleeve 208 preferably includes at least one centering element, and in this embodiment, two centering elements are provided: an upper centering element 270 and a lower centering element 272. The centering elements 270, 272 are preferably attached to the rear portion 224 on opposite sides of the central opening 232 and extend away from the body 220. The centering elements 270, 272 can be identical to each other, or as shown in the figures, one can be different from the other - length, width, etc. In this case, the lower centering element 272 is longer than the upper centering element 270, so that the lower centering element extends beyond the pin fixture 180. The centering elements 270, 272 are used to center the spring 110 on the pin fixture 180 so that an even pressure is provided to the pin fixture 180 and then to the ferrule 20. However, if there is no pin fixture 180, the upper centering element 270 can also be omitted, but the upper centering element is beneficial. Other configurations of the centering elements 270, 272 are also possible.

[0060] The inner sleeve 208 may also include guide pin holes 290, 292 in the rear portion 224 that allow the guide pin 112 to be inserted therethrough and into the pin fixture 180. The inner sleeve 208 may also have dimples 294, 296 on the rear surface of the rear portion 224 that receive protrusions on the pin fixture 180 to better secure the pin fixture 180 to the inner sleeve 108. However, these may also be omitted, particularly where the pin fixture 180 is not used. In the absence of a sleeve slot, the dimples 294, 296 will not interfere with the sleeve slot and may be complete dimples.

[0061] Fig.14 Another embodiment of an inner sleeve 308 according to the present invention is illustrated. The inner sleeve 308 is similar to the previous two embodiments, but has two exceptions. First, the inner sleeve 308 does not have sleeve grooves, but has a larger central opening 332 to allow the optical fibers of the optical fiber ribbon 102 and the ferrule 20 to be more easily inserted into the inner sleeve 308. Second, the guide pin holes 390, 392 are not separate openings through the inner sleeve 308, but the guide pin holes are in communication with the central opening 332 (i.e., interfere with the central opening 322).

[0062] Fig.15 and Fig.16 Another embodiment of an inner sleeve 408 according to the present invention is illustrated. In this embodiment, the inner sleeve 408 is composed of two parts 408a and 408b, which generally correspond to the top part 408a and the bottom part 408b. In this embodiment, there is no need for sleeve grooves, because the optical fibers of the optical fiber ribbon 102 can be disposed in one of the parts, and the other part can then be attached to the first part, capturing the ferrule 20 and the optical fibers of the optical fiber ribbon 102. A latch and receptacle are provided on each of the parts 408a, 408b to secure the parts 408a, 408b to each other. Reference Fig.16 , the top portion 408a has a latch or protrusion 410a and a receptacle 410b on each side thereof. The bottom portion 408b has a latch or protrusion 412a and a receptacle 412b on each side thereof. This is a simple snap fit of the portions 408a, 408b. The remainder of the elements of the portions 408a, 408b are the same or similar to those illustrated and described with reference to the inner sleeves 108, 208 and 308.

[0063] Another embodiment of the connector 500 is Figure 17-19504 and an inner housing 506. The connector 500 may also include a spring 110, a pin fixture 580 or a pin fixture substitute (for a female configuration), and a centering element 570 for the spring 110. A person of ordinary skill in the art will appreciate after reading this disclosure that the centering element 570 is behind the pin fixture 580, which is a departure from standard practice for MPO pin fixtures. In this embodiment, the inner housing 506 has a structure in the central opening 532 that is present on the inner sleeve in previous embodiments for engaging the ferrule 20. That is, the inner housing 506 has a rearward-facing surface 550b and a rearward-facing surface 552b on the protrusions 550 and 552, respectively, to engage the forward-facing surface 26 on the ferrule 20 to assist in retaining the ferrule 20 within the inner housing 506 and the connector 500. While this reduces the number of parts (since no sleeve is required), it also makes the inner housing 506 non-standard for MPO connectors, at least with respect to the front section of the inner housing 506.

[0064] Another embodiment of the multi-fiber connector 600 is Figure 20-26 . In this embodiment, the inner sleeve 608 has been modified to receive a non-MT ferrule, such as ferrule 10', and is still used with the conventional inner housing 606 and outer housing 604 for the MT ferrule 10. The non-MT ferrule 10' as shown has a shoulder, unlike the ferrule 20 which does not have a shoulder. As used herein, a non-MT ferrule refers to any ferrule that does not meet the above description of the MT ferrule 10 (3.0 mm height, 8.05 mm length between the front and rear ends, and 7 mm width). Reference Fig.21 , connector 600 has ferrule 10', inner sleeve 608, guide pins 112 (although they are not required), pin fixture 180, outer housing 604, inner housing 606, and optical fiber 102. Inner housing 606 has rearwardly facing surface 634 inside inner housing 606. Rearwardly facing surface 634 engages sleeve shoulder 630 on inner sleeve 608. See Figure 22-26 .

[0065] The inner sleeve 608 has a rear portion 624, a front portion 626 and a middle portion 628 (see Fig.26 ). A sleeve shoulder 630 is provided between the rear portion 624, and in particular the shoulder 622, and the intermediate portion 628, and the sleeve shoulder is configured to engage a rearwardly facing surface 634 within the inner housing 606. The front portion 626 has a cavity 636 configured to receive the shoulder 12 of the ferrule 10'. See also Fig.25The shoulder 12 of the ferrule 10 ′ disposed within the cavity 636 causes the ferrule 10 ′ to move with the inner sleeve due to the interaction of the shoulder 12 with the forward and rearward facing surfaces of the cavity 636 . The inner sleeve 608 also has a centering element 672 for the spring 110 .

[0066] The inner sleeve 608 can be a single element, or it can also be composed of two different parts combined into a single piece. That is, the two parts can be glued, welded or subjected to another process and still fall within the scope of the present invention.

[0067] A sleeve for holding a non-MT multi-fiber ferrule is provided, the sleeve comprising: a body having a front portion, a middle portion, and a rear portion; a central opening extending longitudinally between the rear end of the rear portion to the front end of the middle portion, the central opening being configured to receive at least one optical fiber ribbon; a cavity in the front portion in front of the central opening and continuous with the central opening, the cavity being at least partially surrounded by a rearward-facing wall at the front end of the cavity and defining another front opening at the front end of the inner sleeve, the rearward-facing wall being configured to engage the non-MT multi-fiber ferrule; a sleeve shoulder formed between the rear portion and the middle portion, the sleeve shoulder being used to engage the inner housing of an MPO optical fiber connector; and at least one centering element being used to support a spring for biasing the sleeve in a forward direction within the inner housing. The body of the sleeve has at least one receptacle at the rear end of the rear portion, the receptacle receiving at least one protrusion from a pin fixture disposed behind the multi-fiber optical fiber ferrule.

[0068] In this respect, the invention also relates to a combination of a sleeve and a non-MT ferrule. This combination can be left in a pulling net of a cable bundle, for example. The pulling net itself is known to a person skilled in the art.

[0069] An MPO connector with a non-MT multi-fiber ferrule, comprising: an outer shell; an inner shell at least partially within the outer shell; an inner sleeve having a body and a ferrule shoulder at a rear portion of the body, the inner sleeve being at least partially positioned within the inner shell and engaged to a ferrule seat within the inner shell; a non-MT multi-fiber ferrule having an optical fiber support structure for holding optical fibers of at least one optical fiber ribbon, the non-MT multi-fiber ferrule being held by the inner sleeve at the ferrule shoulder of the non-MT multi-fiber ferrule; and an MPO spring positioned behind the rear end of the inner sleeve and engaged to the rear end of the inner sleeve to bias the combination of the non-MT multi-fiber ferrule and the inner sleeve in a forward direction, wherein the combination of the inner sleeve and the non-MT multi-fiber ferrule is in a floating configuration within the MPO optical fiber connector.

[0070] It will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention covers modifications and variations of the present invention as long as they fall within the scope of the appended claims and their equivalents.

Claims

1. A multi-fiber optical fiber connector for a multi-fiber optical fiber ferrule, wherein the multi-fiber optical fiber ferrule has at least one row of terminated optical fibers, and the multi-fiber optical fiber connector comprises: outer shell; an inner housing at least partially disposed within the outer housing; an inner sleeve having a body and a shoulder at a rearward portion of the body, the inner sleeve being at least partially positioned within the inner housing and engageable with a rearwardly facing surface within the inner housing and having a central opening; a multi-fiber fiber ferrule having a fiber support structure for retaining optical fibers in the at least one row of terminated optical fibers, the multi-fiber fiber ferrule being engaged by a rearwardly facing surface of the inner sleeve; as well as a spring positioned behind the rear end of the inner sleeve and applying a force to the rear end of the inner sleeve to bias the multi-fiber optical fiber ferrule and the inner sleeve in a forward direction, The combination of the inner sleeve and the multi-fiber optical fiber ferrule is in a floating configuration within the multi-fiber optical fiber connector.

2. The multi-fiber optical fiber connector according to claim 1, wherein: The multi-fiber optical fiber connector is an MPO connector, and the multi-fiber optical fiber ferrule is a TMT ferrule.

3. The multi-fiber optical fiber connector according to claim 1, further comprising a sleeve shoulder formed on the main body, the sleeve shoulder being used to engage with an inner housing of the multi-fiber optical fiber connector.

4. The multi-fiber optical fiber connector according to claim 3, wherein: The sleeve shoulder is disposed between the rear portion and the intermediate portion.

5. The multi-fiber optical fiber connector according to claim 1, further comprising at least one centering element for supporting a spring, the spring for biasing the inner sleeve in a forward direction toward the multi-fiber optical fiber ferrule. 6 . The multi-fiber optical fiber connector according to claim 1 , further comprising a pin fixture disposed between the multi-fiber optical fiber ferrule and the spring.

7. The multi-fiber optical fiber connector according to claim 1, further comprising a sleeve groove formed on one side of the body, the sleeve groove extending longitudinally between the rear portion and the middle portion to allow optical fibers to be inserted into the central opening.

8. The multi-fiber optical fiber connector according to claim 1, wherein: The at least one centering element includes two centering elements disposed on opposite sides of a central opening in the body.

9. The multi-fiber optical fiber connector according to claim 1, wherein: The inner sleeve also includes top and bottom extensions extending in the front portion of the body and away from both the middle and rear portions, each of the top and bottom extensions having a rearwardly facing surface at a free end to engage the multi-fiber fiber stub.

10. A sleeve for receiving a multi-fiber optical fiber ferrule, the sleeve comprising: a body having a front portion, a middle portion, and a rear portion; a top extension and a bottom extension in the front portion and extending away from both the middle portion and the rear portion, each of the top extension and the bottom extension having a rearwardly facing surface at a free end to engage the multi-fiber fiber stub; a central opening extending longitudinally between the rear end of the rear portion and the front end of the intermediate portion and communicating with the space between the top extension and the bottom extension, the central opening being configured to receive at least two optical fibers; a pair of guide pin holes on opposite sides of the central opening and also extending longitudinally between the rear end of the rear portion to the front end of the intermediate portion; a sleeve shoulder formed on the body, the sleeve shoulder being adapted to engage an inner housing of a multi-fiber optical fiber connector; and The middle portion includes at least one ferrule seat between the top extension portion and the bottom extension portion and adjacent to the central opening, and the ferrule seat is used for seating the multi-fiber optical fiber ferrule.

11. The sleeve according to claim 10, wherein: The rear portion of the sleeve has a rearwardly facing rearward portion that encloses the same area as the rearwardly facing rearward portion of the MT ferrule.

12. The sleeve according to claim 10, wherein: The sleeve shoulder is disposed between the rear portion and the intermediate portion.

13. The sleeve of claim 10, further comprising at least one centering element for supporting a spring for biasing the sleeve in a forward direction toward the multi-fiber fiber stub.

14. The sleeve of claim 10, further comprising a sleeve slot formed on one side of the body, the sleeve slot extending longitudinally between the rear portion and the middle portion to allow the at least two optical fibers to be inserted into the central opening.

15. The sleeve according to claim 13, wherein: The at least one centering element includes two centering elements disposed on opposite sides of the central opening.

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