Optical cassettes and related systems

Abstract

The present disclosure relates to fiber optic connection systems that include cassettes which may be mounted within a telecommunication chassis. The cassettes may include spools for storing and dispensing optical cables such that, when an end of the optical cable is pulled, the spool rotates within the cassette and optical cable is dispensed.

Description

Attorney Docket No. 02316.8951WOU1 / 7552WOW1OPTICAL CASSETTES AND RELATED SYSTEMSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is being filed on September 9, 2025, as a PCT International Patent application and claims the benefit of U.S. Provisional Application Serial No. 63 / 693,009 filed September 10, 2024, and claims the benefit of U.S.Provisional Application Serial No. 63 / 784,638 filed April 7, 2025, the entire disclosures of which are incorporated by reference herein.TECHNICAL FIELD

[0002] The present disclosure relates generally to fiber optic connection systems. More particularly, the present disclosure relates to fiber optic connection systems that include optical cassettes.BACKGROUND

[0003] Systems using optical cassettes have been used to provide optical connections in various environments. Such systems can include rack mounted chassis in which optical cassettes can be slidably mounted. The optical cassettes can each include a front row of fiber optic adapters.SUMMARY

[0004] Aspects of the present disclosure relate to a telecommunication cassette adapted to be mounted within a telecommunication chassis. In certain examples, the telecommunication cassette includes a cassette body having a width, a depth, and a height; wherein the width extends between opposite first and second sides of the cassette body, the depth extends between opposite front and back ends of the cassette body and the height extends between top and bottom sides of the cassette body. In certain examples, the cassette body includes front fiber-optic adapters mounted adjacent to the front end of the cassette body, each including of the front fiber-optic adapters a front port facing in a forward direction and a rear port facing in a rearward direction. Incertain examples the cassette body defines spool recess located adjacent to the back end of the cassette body and a fiber routing region located between the spool recess and the fiber optic adapters. In certain examples, the cassette body includes a center reference line that extends in a forward / rearward orientation and that bisects the width of the cassette body.

[0005] In certain examples, the telecommunication cassette includes a spool that mounts within the spool recess, the spool being capable of rotating relative to the cassette body about a rotation axis which extends in an upward / downward orientation and which is offset from the center reference line in a first offset direction. In certain examples, the cassette body defines a rear adapter mounting location adjacent to the back end of the cassette body for mounting a rear fiber optic adapter; the rear adapter mounting location being offset in a second offset direction from the center reference line, where the second offset direction is opposite from the first offset direction. In certain examples the rear fiber optic adapter includes a front port facing in the forward direction and a rear port facing in the rearward direction. In certain examples, the telecommunication cassette further includes an optical cable having first and second opposite ends which can be wrapped about the spool, and where the optical cable can be dispensed from the spool by pulling on the first end of the optical cable causing the spool to rotate about the rotation axis relative to the cassette body as the optical cable is dispensed from the spool.

[0006] Other aspects of the present disclosure relate to a telecommunication cassette adapted to be mounted within a telecommunication chassis. In certain examples, the telecommunication cassette includes a cassette body having a width that extends between opposite first and second sides of the cassette body, a depth that extends between opposite front and back ends of the cassette body and a height that extends between top and bottom sides of the cassette body. In certain examples, the cassette body includes front fiber-optic adapters mounted adjacent to the front end of the cassette body, the front fiber-optic adapters each including a front port facing in a forward direction and a rear port facing in a rearward direction.

[0007] In certain examples, the telecommunication cassette includes a spool carried with the cassette body, the spool being rotatable relative to the cassette body about a rotation axis that extends in an upward / downward orientation. In certain examples the spool includes a spool core coaxially aligned with the rotation axis, andtop and bottom spool flanges that project radially outwardly from the spool core. In certain examples, the telecommunication cassette includes an optical cable wrapped about the spool core and contained between the top and bottom spool flanges. In certain examples, the optical cable includes first and second opposite ends, where the optical cable can be dispensed from the spool by pulling on the first end of the optical cable causing the spool to rotate about the rotation axis relative to the cassette body, and wherein a fiber optic connector is attached to the second end of the optical cable.

[0008] In certain examples, the telecommunication cassette further includes a connector holder that detachably mounts within the spool core for holding the fiber optic connector such that the fiber optic connector rotates in unison with the spool about the rotation axis as the optical cable is dispensed from the spool. In certain examples the connector holder projects above the top side of the cassette body when mounted within the spool core and is configured for holding the fiber optic connector above the top spool flange.

[0009] Further aspects of the present disclosure relate to a telecommunication system including a chassis configured to be secured to a telecommunication rack including a main chassis body and a rear cover that detachably mounts to the rear end of the main chassis body; first cassettes configured to be installed within the chassis and used in combination with the rear cover; and second cassettes configured to be mounted within the chassis and used with the rear cover removed. In certain examples, the main chassis body includes a front end and a rear end. In certain examples, the chassis including side flanges adjacent to the front end of the main chassis body for securing the chassis to a rack. In certain examples, the rear cover includes a rear wall defining a vertical reference plane when the rear cover is mounted to the main chassis body. In certain examples, when the first cassettes are installed within the chassis, the first cassettes do not extend rearwardly beyond the vertical reference plane. In certain examples the second cassettes include rotatable spools that can be rotated with respect to the cassettes to allow optical cables to be dispensed from the cassettes and which partially project rearwardly beyond the vertical reference plane when the second cassettes are installed within the chassis.

[0010] A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and thefollowing 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

[0011] FIG. 1 is a perspective view of a telecommunication chassis in accordance with the principles the present disclosure;

[0012] FIG. 2 is a top view of the telecommunication chassis of FIG. 1 ;

[0013] FIG. 3 A is a perspective view of a cassette in accordance with the principles the present disclosure;

[0014] FIG. 3B is a perspective view of another cassette in accordance with the principles the present disclosure;

[0015] FIG. 3C is a perspective view of another cassette in accordance with the principles the present disclosure;

[0016] FIG. 3D is a perspective view of another cassette in accordance with the principles the present disclosure;

[0017] FIG. 3E is a perspective view of another cassette in accordance with the principles the present disclosure;

[0018] FIG. 4 is another perspective view of the telecommunication chassis of FIG. 1 depicting the removable rear cover;

[0019] FIG. 5 is a perspective view of another telecommunication cassette in accordance with the present disclosure;

[0020] FIG. 6 is another perspective view of the telecommunication cassette of FIG. 5 depicting the fiber routing region;

[0021] FIG. 7 is a top view of the telecommunication cassette of FIG. 5;

[0022] FIG. 8 is a bottom view of the telecommunication cassette of FIG. 5;

[0023] FIG. 9 is a right-side view of the telecommunication cassette of FIG. 5;

[0024] FIG. 10 is a left side view of the telecommunication cassette of FIG. 5;

[0025] FIG. 11 is a cross-sectional view of a pair of front fiber-optic adapters in accordance with the present disclosure;

[0026] FIG. 12 is an alternate top view of the telecommunication cassette of FIG. 5 depicting the fiber routing region including plurality of optical fibers;

[0027] FIG. 12A is a cross-sectional view of a rear adapter mounting location in accordance with the present disclosure;

[0028] FIG. 13 is a perspective view of a connector holder including a fiber optic connector in accordance with the present disclosure;

[0029] FIG. 14 is an alternate perspective view of the connector holder of FIG. 13;

[0030] FIG. 15 is a front view of the connector holder of FIG. 13 ;

[0031] FIG. 16 is a side view of the connector holder of FIG. 13;

[0032] FIG. 17 is a top view of the connector holder of FIG. 13;

[0033] FIG. 18 is a bottom view of the connector holder of FIG. 13;

[0034] FIG. 19 is a perspective view of a spool including an optical cable, a connector holder, and a fiber optic connector in accordance with the present disclosure;

[0035] FIG. 20 is an alternate perspective view of the spool of FIG. 19 including an optical cable;

[0036] FIG. 21 is a top view of the spool of FIG. 19 including an optical cable;

[0037] FIG. 22 is a bottom view of the spool of FIG. 19 including an optical cable;

[0038] FIG. 23 is an alternate perspective view of the spool of FIG. 19;

[0039] FIG. 24 is an alternate top view of the spool of FIG. 19;

[0040] FIG. 25 is aside view of the spool of FIG. 19;

[0041] FIG. 26 is an alternate perspective view of the cassette of FIG. 5 depicting the spool recess;

[0042] FIG. 27 is a partially exploded perspective view of the cassette of FIG. 5;

[0043] FIG. 28 is an alternate partially exploded perspective view of the cassette ofFIG. 5;

[0044] FIG. 29 is a top view of the cassette of FIG. 5 depicting the spool recess and the fiber routing region;

[0045] FIG. 30 is a perspective view of the telecommunication system in accordance with the present disclosure including cassettes and fiber management loops and wherein the rear cover of the chassis has been removed;

[0046] FIG. 31 is a top view of the telecommunication system of FIG. 30;

[0047] FIG. 32 is a bottom view of the telecommunication system of FIG. 30;

[0048] FIG. 33 is a right-side view of the telecommunication system of FIG. 30;

[0049] FIG. 34 is a left side view of the telecommunication system of FIG. 30;

[0050] FIG. 35 an alternate perspective view of the telecommunication system of FIG. 30 including cassettes and fiber management loops and wherein the rear cover of the chassis has been removed;

[0051] FIG. 36 is an alternate top view of the telecommunication system of FIG. 30;

[0052] FIG. 37 is a front side view of the telecommunication system of FIG. 30;

[0053] FIG. 38 is a rear side view of the telecommunication system of FIG. 30;

[0054] FIG. 39 is a perspective view of a fiber management loop in accordance with the present disclosure;

[0055] FIG. 40 is top view of the fiber management loop of FIG. 39;

[0056] FIG. 41 is a right-side view of the fiber management loop of FIG. 39;

[0057] FIG 42 depicts a rear extension assembly shown mounted at a rear end of the chassis of FIG. 1 in place of a rear cover of the chassis of FIG. 1;

[0058] FIG. 43 is an exploded view of the rear extension assembly of FIG. 42;

[0059] FIG. 44 is a top view of the chassis and rear extension assembly of FIG. 42;

[0060] FIG. 45 is a front, perspective view of an alternative cassette in accordance with the principles of the present disclosure, the cassette can be rear loaded into the chassis of FIG. 1;

[0061] FIG. 46 is a rear, perspective view of the cassette of FIG. 45 with a spool rotation locking arrangement in a non-locked state;

[0062] FIG. 47 is a rear, perspective view of the cassette of FIG. 45 with the spool rotation locking arrangement in a locked state;

[0063] FIG. 48 is another perspective view of the cassette of FIG. 45;

[0064] FIG. 49 depicts the cassette of FIG. 45 being loaded into the rear end of the chassis of FIG. 1;

[0065] FIG. 50 depicts the cassette of FIG. 45 positioned above a main spool for storing excess cable length beyond the storage capacity of the cassette spool;

[0066] FIG. 51 depicts the cassette of FIG. 45 mounted at an axial end face of the main spool of FIG. 50;

[0067] FIG. 52 is a top view showing the cassette of FIG. 45 mounted on the axial end face of the main spool of FIG. 50;

[0068] FIG. 53 is a perspective view of a cassette spool in accordance with the principles of the present disclosure mounted between supplemental spool flanges for containing excess cable length beyond the storage capacity of the cassette spool;

[0069] FIG. 54 depicts the arrangement of FIG. 53 with the upper supplemental spool flange removed;

[0070] FIG. 55 depicts the arrangement of FIG. 54 with the excess cable length removed;

[0071] FIG. 56 depicts an alternative arrangement where multiple cassettes pools are installed between a pair of the supplemental flanges; and

[0072] FIG. 57 depicts the arrangement of FIG. 56 with the upper supplemental flange removed and with one of the cassette spools exploded above a remainder of the cassette spools.

[0073] FIG. 58 illustrates an alternative arrangement of a main spool.DETAILED DESCRIPTION

[0074] FIGS. 1 and 2 depict a telecommunication chassis 20 in accordance with the principles of the present disclosure. The telecommunication chassis 20 is configured to be secured to a telecommunication rack. The telecommunication chassis 20 includes a main chassis body 22 having a front end 24 and a rear end 26. The telecommunication chassis 20 also includes a top 27, a bottom 28, a left side 30 and a right-side 32. Side flanges 34 for securing the telecommunication chassis 20 to the rack are provided at the left and right-sides 30, 32 adjacent the front end 24. The main chassis body 22 includes a plurality of cassette mounting locations within the main chassis body 22. The cassette mounting locations are configured for allowing cassettes to be slid into the main chassis body 22 from the front end 24 of the main chassis body 22 and from the rear end 26 of the main chassis body. Similarly, the cassette mounting locations are configured for allowing cassettes to be removed from the main chassis body 22 from the front and 24 and from the rear end 26 of the main chassis body 22. The cassette mounting locations can be defined by grooves, rails, tracks, or other structures. In the depicted example, the cassette mounting locations accommodate a first pair of cassettes at a lower level and a second pair of cassettes at an upper level. The cassettes are mounted in a side-by-side configuration at each of the levels. In other examples, more than two levels can beprovided within the chassis. A front door 39 can be pivoted to an open position to facilitate accessing the front of the main chassis body 22.

[0075] The telecommunication chassis 20 can also include a rear cover 36 that the detachably mounts to the rear end 26 of the main chassis body 22. The rear cover 36 includes a rear wall 38 defining a vertical back reference plane RP when the rear cover 36 is mounted to the rear end 26 of the main chassis body 22. The rear cover 36 can be used to enclose the rear end 26 of the main chassis body 22 but can be detached from the main chassis body 22 to access cassettes (e.g., to allow cassettes to be inserted into or removed from the main chassis body 22 through the rear end 26). Detachment of the rear cover 36 also allows certain types of cassettes having a depth larger than the depth of the main chassis body 22 to be installed in the main chassis body 22. The main chassis body 22 includes a first connection arrangement 40 that interfaces with a second connection arrangement 42 of the rear cover 36 to secure the rear cover 36 to the main chassis body 22. In the depicted example, the first connection arrangement 40 includes a plurality of openings 44 (e.g., sockets, receptacles, etc.) and the second connection arrangement 42 includes a plurality of projections 46 configured to mate within the openings 44. In certain examples, the projections 46 can be secured within the openings 44 by a snap-fit interlock.

[0076] FIG. 3 depicts various optical cassettes 47a-e configured to be mounted within the telecommunication chassis 20 and use in combination with the rear cover 36. It will be appreciated that each of the optical cassettes 47a-e is depicted including a row of front fiber optic adapters 50 that are accessible at the front end 24 of the telecommunication chassis 20 when the optical cassettes 47a-e are installed within the telecommunication chassis 20. The optical cassettes 47a-e have opposite sides respectively including a latching arrangement 52 and a slide rail 54. The optical cassettes 47a-e each have a depth less than the depth of the main chassis body 22 such that the rear cover 36 can be mounted to the rear end 26 of the main chassis body 22 without interference from the cassettes 47a-e.

[0077] Optical cassette 47a can be a patching cassette in which connectorized ends of a patch cord are routed through a rear of the optical cassette 47a and plugged into rear ports of the fiber-optic adapters 50. Optical cassette 47b can be a splice cassette in which a cable is routed through a rear of the optical cassette 47b and optical fibers of the cable are spliced to connectorized fiber-optic pigtails having connectorized endsplugged into rear ports of the fiber optic adapters 50. The optical cassette 47b can include splice trays for holding the splices. Optical cassette 47c can be a splitter cassette including one or more passive optical power splitters having inputs optically connected to optical fibers of cables routed to the splitter cassette 47c (e.g., through the rear of the cassette 47c) and outputs optically connected to connectorized optical pigtails having connectorized ends plugged into rear ports of the fiber optic adapters 50 or routed out through the front of the cassette 47c through pass-through openings located at the front of the cassette 47c. Optical cassette 47d can be a distribution cassette having at least one rear multi-fiber connection interface that can include a multi-fiber adapter having a front port and a rear port. A multi-fiber connector can be installed within the front port of the multi-fiber adapter. Optical fibers can connect the multi-fiber connector to single fiber connectors installed within rear ports of the fiberoptic adapters 50. Optical cassette 47e can be a CMOD cassette having an optical cable routed through a rear of the optical cassette 47e and anchored (e.g., crimped) to the optical cassette 47e. Optical fibers of the cable can be terminated by fiber optic connectors such as single-fiber optical connectors that are plugged into rear ports of the fiber-optic adapters 50.

[0078] FIGS. 5-10 depict an optical cassette 60 in accordance with the principles of the present disclosure. The optical cassette 60 is configured to be mounted within the telecommunication chassis 20. However, in one example, the optical cassette 60 can have a depth greater than the depth of the main chassis body 22. Thus, when the optical cassette 60 is installed within the main chassis body 22, a rear portion of the optical cassette 60 projects rearwardly past the rear end 26 of the main chassis body 22 (see FIGS. 30-34). Hence, when a plurality of the optical cassettes 60 are installed within the telecommunication chassis 20, the rear cover 36 is removed and not connected to the rear end 26 of the main chassis body 22. By not using the rear cover 36, the optical cassettes 60 can protrude rearwardly past the back reference plane RP when the optical cassettes 60 are installed within the main chassis body 22. In certain examples, cable management loops 62 (see FIGS. 30-36 and 39-41) can be connected to the rear end 26 of the main chassis body 22 in place of the rear cover 36. The cable management loops 62 can include connection arrangements adapted to engage with (e.g., mate with) the first connection arrangement 40 at the rear end 26 of the main chassis body 22. Forexample, the cable management loops 62 can include projections 64 that fit within the openings 44 of the first connection arrangement 40.

[0079] FIGS. 42-44 depict alternative cable management loops 262 that are configured to extend the depth of the main chassis body 22 to accommodate optical cassettes with integrated spooling such as cassettes 60 or cassettes 360. The cable management loops 262 include front connection arrangements adapted to engage with (e.g., mate with) the first connection arrangement 40 at the rear end 26 of the main chassis body 22. For example, the cable management loops 262 can include projections or first connecting members 264 that fit within the openings 44 of the first connection arrangement 40. The cable management loops 262 can include cable routing openings 263 bound in part by curved bend radius limiting surfaces 261. The cable management loops 262 can also include extension portions 267 sized to extend rearwardly far enough to accommodate the cassettes 60. Rear ends of the cable management loops 262 can include cable access slots 269 for allowing a cable to be passed into the cable routing opening in a rearward to forward direction. The rear ends of the of the cable management loops 262 also include connection arrangements for allowing a pivotal rear panel 271 to be attached to the rear ends of the cable management loops 262. The panel 271 can be pivotally connected to connecting members 273 that fit within lower sockets 275 at the rear ends of the cable management loops 262 and panel latches can be integrated into connecting members 276 that fit into upper sockets 277 at the rear ends of the cable management loops 262. FIGS. 42 and 44 show how the cable management loops 262 extend the depth of the main chassis an amount sufficient for the panel 271 to be closed behind the cassettes 360 when the cassettes 360 are mounted in the main chassis.

[0080] The cable management loops 262 can be referred to as an extension assembly adapted to be mounted to a rear end of the chassis. The extension assembly can include extension bodies 500 having front ends and rear ends. The extension bodies 500 define the cable routing openings 263. First connecting members 264 are used to connect the front ends of the extension bodies of the extension assembly to the rear end of the chassis. Second connecting members 273, 276 are used for connecting the rear ends of the extension bodies to a pivotal rear panel 271.

[0081] Referring to FIGS. 5-10, the telecommunication cassette 60 incudes a cassette body 66 including a width W that extends between opposite first and secondsides 68, 70 (e.g., left and right-sides) of the cassette body 66. The cassette body also includes a depth D that extends between opposite front and back ends 72, 74 of the cassette body 66. A height H of the cassette body 66 extends between top and bottom sides 76, 78 of the cassette body 66. A rail 80 for engaging a complementary structure within the main chassis body 22 can be provided at the second side 70 of the cassette body 66 and a latching arrangement 82 for latching the optical cassette 60 within the telecommunication chassis 20 can be provided at the first side 68 of the cassette body 66. The latching arrangement 82 can include a front latch portion 82a adapted to be accessible from the front of the chassis 20 and a rear latch portion 82b adapted to be accessible from the rear of the chassis 20. The telecommunication cassette 60 can be slid in and out of the chassis 20 through the front end 24 of the chassis 20 and also can be slid in and out of the chassis 20 through the rear end 26 of the chassis 20. The front latch portion 82a can be adapted to engage a front catch provided within the chassis 20, and the rear latch portion 82b can be configured to engage a rear catch provide within the chassis 20. The front and rear latch portions 82a, 82b can be configured as resilient latching arms that are biased toward a retaining position in which the front and rear latch portions 82a, 82b are adapted to engage their corresponding catches to retain the optical cassette 47a within the main chassis body 22. By flexing the resilient latching arms from the retaining position to a release position, the optical cassette 60 can be removed from the main chassis body 22. For example, by flexing the front latch portion 82a to the release position, the front latch portion 82a disengages from the front catch of the main chassis body 22 allowing optical cassette 60 to be removed from the main chassis body 22 through the front end 24 of the main chassis body 22. By flexing the rear latch portion 82b to the release position, the rear latch portion 82b disengages from the rear catch of the main chassis body 22 allowing the optical cassette 60 to be removed from the main chassis body 22 through the rear end 26 of the main chassis body 22. The front and rear latch portions 82a, 82b can include ramp surfaces for allowing the front latch portion 82a to snap past the front catch when the optical cassette 60 is loaded into the main chassis body 22 through the front end 24, and for allowing the rear latch portion 82b to snap past the rear catch when the cassette 60 is loaded into the main chassis body 22 through the rear end 26.

[0082] The optical cassette 60 includes front fiber-optic adapters 90 mounted adjacent the front end 72 of the cassette body 66. In certain examples, the front fiberoptic adapters 90 can be arranged in one or more rows. As depicted, the front fiber optic adapters 90 coupled to a front adapter mount 92 (e.g., an adapter block, an adapter holder, etc.) that attaches to the front end 72 of the cassette body 66. In one example, the front adapter mount 92 can attach to the front end 72 of the cassette body 66 by a snap-fit connection which is engaged by inserting the front adapter mount 92 in a front to rear direction into engagement with the cassette body 66. As depicted at FIG. 11, the fiber optic adapters 90 each including a front port 93 facing in a forward direction and a rear port 94 facing in a rearward direction. The fiber optic adapters 90 are configured for coupling together single-fiber optical connectors inserted into the front and rear ports 93, 94 and include ferrule alignment sleeves 96 adapted for coaxially aligning ferrules of the connectors. In the depicted example, the fiber optic adapters 90 are SC fiber optic adapters. In the depicted example, the fiber optic adapters 90 are aligned in a single row including twelve of the fiber-optic adapters. In an alternative example, the SC fiber optic adapters can be replaced with LC fiber optic adapters. It will be appreciated that by using LC fiber optic adapters, a larger number of adapters can be provided on the optical cassette 60. In one example, by using LC fiber optic adapters, the number of adapters provided on the optical cassette 60 can be doubled (e.g., twenty- four fiber optic adapters can be provided). In alternative examples, one or more fiber optic adapters adapted for coupling multi-fiber optical connectors can be provided at the front of the optical cassette 60. In certain examples, to enhance finger access, the fiber optic adapters 90 or modules supporting the fiber optic adapters can pivot relative to the cassette body 66 about a horizontal axis that extends across the width W of the cassette body 66.

[0083] Referring to FIG. 12, the cassette body 66 defines a fiber routing region 98 and a spool recess 100. The fiber routing region 98 can be covered by a removable top cover 101 that removably mounts to the cassette body 66. The spool recess 100 is located adjacent the back end 74 of the cassette body 66 and the fiber routing region 98 being located between the spool recess 100 and the front fiber optic adapters 90. The cassette body 66 includes a center reference line CL that extends in a forward / rearward orientation and that bisects the width W of the cassette body 66. A spool 102 mounts within the spool recess 100. The spool 102 is rotatable within the spool recess 100 relative to the cassette body 66 about a rotation axis 104 that extends in anupward / downward orientation. The rotation axis 104 being offset in a first offset direction DI from the center reference line CL by a first offset distance DIS1.

[0084] The cassette body 66 defines a rear adapter mounting location 106 adjacent the back end 74 of the cassette body 66 for mounting a rear fiber optic adapter 108. The rear adapter mounting location 106 is offset in a second offset direction D2 from the center reference line CL. The second offset direction D2 is opposite from the first offset direction DI. The spool recess 100 and the rear adapter mounting location 106 occupy non-overlapping regions of the width W of the cassette body 66.

[0085] The rear fiber optic adapter 108 has a front port 110 facing in the forward direction and a rear port 112 facing in the rearward direction. In a preferred example, the rear fiber-optic adapter 108 is adapted for coupling together two multi-fiber optical connectors such as MPO connectors. Thus, the rear fiber optic adapter 108 can be an MPO adapter. More than one of the rear fiber optic adapters 108 can be provided at the rear adapter mounting location 106. As depicted, two rear fiber optic adapters 108 are provided. It will be appreciated that the multi-fiber optical connectors received at the rear fiber optic adapters 108 can have different numbers of fiber counts (e.g., eight fibers, 12 fibers, 16 fibers, 24 fibers). In one example, where the front fiber optic adapters 90 include twelve SC fiber-optic adapters, one of the rear fiber-optic adapters 108 is used to provide an optical connection interface with the fiber optic adapters 90. For example, as shown at FIG. 12, a 12-fiber MPO connector 114 can be received within the front port 110 of the fiber-optic adapter 108 and optically coupled to single fiber optical connectors 116 received within the rear ports 94 of the front fiber optic adapters 90 by optical fibers 118 routed though the fiber routing region 98. Where the front fiber optic adapters 90 include twenty-four LC fiber optic adapters, both of the fiber-optic adapters 108 can be utilized to accommodate the higher fiber count.

[0086] The optical cassette 60 includes an optical cable 120 wrapped about the spool 102. The optical cable 120 has first and second opposite ends 122, 124. The optical cable 120 can be dispensed from the spool 102 by pulling on the first end 122 of the optical cable 120 causing the spool 102 to rotate about the rotation axis 104 relative to the cassette body 66 as the optical cable 120 is dispensed from the spool 102. As the optical cable 120 is dispensed from the spool 102, the second end 124 of the optical cable 120 is carried by the spool 102 and rotates in unison with the spool 102 about the rotation axis 104. In one example, the first and second ends 122, 124 of the opticalcable are terminated by fiber optic connectors (e.g., multi-fiber optical connectors such as MPO connectors). The fiber optic connector at the second end 124 of the optical cable 120 can be carried with and rotated in unison with the spool 102 as the optical cable 120 is dispensed from the spool by pulling on the first end 122 of the optical cable 120. After dispensing / deployment of the optical cable, the fiber optic connector at the second end 124 of the optical cable 120 can be detached from the spool 102 and plugged into the rear port 112 of the rear fiber optic adapter 108. In this way, fiber optic connector at the second end 124 of the optical cable 120 optically couples with the fiber optic connector 114 at the front port of the rear adapter 108 such that the optical fibers of the optical cable 120 are coupled to the single fiber optical connectors 116 installed at the front adapters 90 by the optical fibers 118 routed through the fiber routing region 98.

[0087] In the depicted example, the optical cable 120 is a multi-fiber optical cable with the first end 122 of the optical cable 120 shown including a first multi-fiber optical connector 130 (e.g., an MPO connector) and the second end 124 of the optical cable 120 shown including a second multi-fiber optical connector 132 (e.g., and MPO connector). FIGS. 5-7 show the second multi-fiber optical connector 132 mounted on the spool 102 such that the second multi-fiber connector 132 can be carried with the spool 102 and can rotate in unison with the spool about the rotation axis 104 as the optical cable 120 is dispensed from the spool 102. After the optical cable 120 has been dispensed from the spool 102, the second multi-fiber optical connector 132 can be removed / detached from the spool 102 and plugged into the rear port 112 of the rear fiber optic adapter 108. FIG. 12 shows the second multi-fiber connector 132 removed from the spool 102 and plugged into the rear port 112 of the rear fiber optic adapter 108 after deployment of the optical cable 120.

[0088] In certain examples, more than one optical cable can be wrapped around the spool 102. For example, in the case where the optical cassette 60 can accommodate twenty-four optical connections at the front adapters 90, two twelve— fiber optical cables can be wrapped about the spool 102. The ends of such optical cables can be terminated by 12-fiber MPO connectors. After deployment of the cables, the MPO connectors at the second ends of the cables can be plugged into the rear ports 112 of the rear fiber optic adapters 108 to optically connect the optical fibers of the multi-fiberoptical cables to the single-fiber optical connectors installed within the rear ports of the front fiber optic adapters 90.

[0089] Referring to FIGS. 20-25, the spool 102 includes a spool core 140 coaxially aligned with the rotation axis 104. The spool 102 also includes top and bottom spool flanges 142, 144 that project radially outwardly from the spool core 140 wherein the optical cable 120 is wrapped about the spool core 140 and is contained between the top and bottom spool flanges 142, 144. The bottom spool flange 142 includes a plurality of rotation locking openings 146 spaced about the axis of rotation 104 adjacent an outer perimeter of the bottom spool flange 142. The bottom spool flange 142 also defines an annular groove 148 centered about the axis of rotation 104. In certain examples, at least one of the top and bottom spool flanges 142, 144 defines an outer cross dimension (e.g., an outer diameter) that is at least 60% , or at least 70 percent, or at least 80 percent as large as the width W of the cassette body 66. In certain examples, at least one of the top and bottom spool flanges 142, 144 defines an outer cross dimension (e.g., an outer diameter) that is 60-90 percent as large as the width W of the cassette body 66.

[0090] The cassette body 66 includes a recess-defining portion 150 that defines the spool recess 100. The recess-defining portion 150 includes a bottom wall 154 for opposing the bottom spool flange 144 when the spool 102 is mounted within the spool recess 100. The cassette body 66 includes an annular rotation guide 156 that projects upwardly from the bottom wall 154 for fitting within the annular groove 148 of the bottom spool flange 142 for guiding rotation of the spool 102 relative to the cassette body 66 about the rotation axis 104. The recess-defining portion 150 also includes a circumferential wall 157 adapted to extend circumferentially about an outer periphery of at least a portion of at least one of the top and bottom spool flanges 142, 144 when the spool 102 is mounted within the spool recess 100. The circumferential wall 157 is configured to extend about a first circumferential portion Cl of the top spool flange 142 when the spool 102 is mounted within the spool recess 100 and is configured to extend about a second circumferential portion C2 of the bottom spool flange 144 when the spool 102 is mounted within the spool recess 100. The second circumferential portion C2 is circumferentially longer than the first circumferential portion Cl. As depicted, the first circumferential portion Cl extends for at least 200° about the rotation axis.

[0091] The botom wall 154 includes a resilient latch 160 movable between a retaining position and a release position. The resilient latch 160 is unitary with the botom wall 154 and is biased toward the retaining position. The resilient latch 160 being is configured to prevent rotation of the spool 102 relative to the cassete body 66 when in the retaining position and is configured to allow rotation of the spool 102 relative to the cassete body 66 when in the release position. The resilient latch 160 can be manually flexed to the release position when it is desired to dispense cable from the spool 102 by rotating the spool 102 relative to the cassete body 66 or when it is desired to wrap excess cable on the spool 102 by rotating the spool 102 relative to the cassete body 66. The resilient latch 160 can engage the rotation locking openings 146 to lock rotation of the spool 102 relative to the cassete body 66. The openings 146 allow the spool 102 to be rotationally locked at a plurality of rotational positions.

[0092] The optical cassete 60 includes a connector holder 170 (see FIGS. 5-7 and 13-19) that mounts in the spool core 140 for holding the fiber optic connector 132 at the second end 124 of the optical cable 120 during dispensing of the optical cable 120 from the spool 102. The connector holder 170 projects above the top side of the cassete body 66 when mounted within the spool core 140 such that the fiber optic connector 132 is held at a location above the top side of the cassete body 66. The connector holder 170 is removable from the spool 102 after the optical cable 120 has been dispensed from the spool 102. In certain example, the connector holder 170 will interfere with loading of the cassete 60 within the chassis 20 if not removed since the connector holder projects outside the formfactor of the cassete and the formfactor of the cassette receiving region of the chassis 20. The connector holder 170 holds the fiber optic connector 132 by a first snap-fit connection (e.g., provide by resilient latches 172), and is secured within the spool core 140 by a second snap-fit connection (e.g., provided by resilient latches 174). The connector holder 170 mates within the core 174 and is non-rotatable relative to the core 140. The holder can be configured to hold two connectors (e.g., two MPO connectors).

[0093] FIGS. 45-48 depict another cassete 360 having a configuration similar to the cassette 60. Similar to the cassete 60, the cassete 360 includes the front adapter mount 92 holding fiber optic adapters 90, the rear fiber optic adapter 108 (e.g., at least one a multi-fiber optical adapter), and a spool recess 300 defined by a circumferential wall 357, and a spool 302 on which a cable 120 having a first end 122 and a second end124 is coiled. The spool 302 includes an upper flange 344 and a lower flange 342. With regard to the cassette 360, a cassette body 366 has been modified to add a bend radius limiters 311 (see FIG. 46) at opposite ends of a rear cable dispensing opening 312 which communicates with the spool recess 300. The rear cable dispensing opening 312 allows the cable 120 to be paid off from the spool as the first end 122 is pulled causing rotation of the spool 302. The cable being deployed is pulled through the opening 312 as the first end 122 is pulled and the spool 302 rotates within the recess 300. After deployment of the cable 120, the second end 124 of the cable 120 can also be routed through the rear cable dispensing opening 312 along a routing path to the multi-fiber adapter 108. The routing path to the multi-fiber adapter 108 is defined by one of the bend radius limiters 311 and by cable management fingers 313 arranged for capturing and guiding the portion of the cable adjacent to the second end 124. The fingers 313 are provided on an outer surface 315 that extends from the rear cable dispensing opening 312 to the location of the multi-fiber fiber optic adapter 108. At least a portion of the outer surface 315 generally matches an outer contour defined by the outer circumference of the upper flange 344 of the spool 302. The spool 302 is adapted to rotate within the spool recess 300 about a central axis of the spool that, when the spool 302 is mounted in the spool recess 300, co-axially aligns with an axis around which the circumferential wall 357 extends.

[0094] The spool 302 includes a spool core 340 about which the fiber-optic cable 120 is coiled. A connector storage recess 341 (e.g., a pocket, cavity, volume, hollow region, etc.) is defined within the spool core 340. The multi-fiber fiber optic connector at the second end 124 of the cable 120 is stored within the recess 341 until after the cable 120 has been deployed. A connector holder 343 that is integral with the spool 302 is provided in the recess 341. The recess 341 is also configured to allow for the storage of cable within the recess 341. For example, a length of cable sufficient to extend from the spool 302 to the multi-fiber adapter 108 or longer can be stored in the recess 341. An inner surface 345 of an annular core wall 339 forming the core 340 surrounds and defines the recess 341. Cable retention fingers 347 project radially inwardly from the inner surface 345 and extend over an outer region of the recess 341 to assist in retaining excess cable length in the recess 341. The connector holder 343 is located in a gap between opposing flat sides of half-spools 349 located in the recess 341. The half-spools 349 are integrally formed with the spool 302. The annular wall339 defines an upper opening 337 that aligns with a spool flange opening 335 in the upper flange 344 of the spool 302. When the second end 124 of the cable 120 is stored in the recess 341, the end portion of the cable 120 corresponding to the second end 124 transitions from an inner diameter of the spool defined by the outer surface annular core wall 339 through the upper opening 337 and into the recess 341. Excess length of the cable adjacent the second end 124 can be stored (e.g., coiled in a loop, coiled in a figure 8, etc.) within the recess 341.

[0095] The cable 120 extends from the outer diameter of the spool 302 to the first end 122 of the cable 120. Prior to and during deployment of the cable 120 by pulling on the first end 122 of the cable cause the spool 302 to rotate and the cable 120 to be paid off the spool 302, the second end 124 of the cable 120 remains stowed in the recess 341 such that the second end 124 is carried by the spool 302 as the spool rotates. After cable deployment, the second end 124 of the cable can be removed from the recess 341 and passed through the upper opening 337, the spool flange opening 335 and the rear cable dispensing opening 312 to route the second end 124 to the fiber optic adapter 108. The upper opening 337 can have rounded ends to prevent excessive bending of the portion of the cable 120 routed into the recess 341.

[0096] The cassette 360 includes a locking arrangement for locking rotation of the spool 302 relative to the cassette body 366 about the central spool axis. The locking arrangement preferably locks the spool 302 in a rotational position in which the upper opening 337 and the spool flange opening 335 at least partially overlap and preferably align with the rear cable dispensing opening 312 of the cassette body 366. In certain examples, the spool can only be locked in one position or alternatively in a location within a single locking sector, in which the upper opening 337 and the spool flange opening 335 at least partially overlap with the rear cable dispensing opening 312 of the cassette body 366 In one example, the upper flange 344 of the spool 302 defines radial locking notches 379 at an outer circumference of the upper flange 344. The locking notches are adapted to interlock with a slide lock 381 to lock rotation of the spool 302. The slide lock is mounted on the body of the cassette at a location radially outside the spool 302 and is radially moveable relative to the spool 302 between a locking inner position and an unlocking outer position. The slide lock 381 has a tooth adapted to slide radially within a selected one of the locking notches 379 to lock rotation of the spool 302. The locking notches 379 correspond to only a limited sector 380 of thespool 302 and are not spaced fully about the spool. In one example, the sector is less than 45 degrees. The sector 380 and slide lock are configured to ensure that the upper opening 337 and the spool flange opening 335 face rearwardly when the spool is locked. In other example, the slide lock can be on the spool and the notches can be defined by the cassette body.

[0097] Similar to previous examples, the cassettes 360 load into the chassis form the rear of the chassis and are removeable from the chassis from the ear of the chassis.

[0098] The cassette body 366 can define a mandrel opening 390 at a location offset from the spool recess 300 and the central axis of rotation of the spool 302. Prior to mounting in the chassis, the cassette 360 can be mounted at the axial end face 400 of a main spool 402. As depicted at FIGS. 50-52, the cassette mount 360 in a pocket defined by the axial end face 400 with a central hollow post 404 of the main spool fitting within the mandrel opening 390. The main spool 402 can be constructed of a material such as plastic or cardboard. (Shown in FIG. 57). Excess cable length that exceeds the capacity of the spool 302 can be coiled about the main spool 402. The axial end face 400 of the main spool 402 can include a side opening 406 that is positioned adjacent to the spool 302 when the cassette 360 is mounted within the pocket at the end face of the main spool 402. The extra fiber length beyond the capacity of the spool 302 can be routed through from the spool 302 through the side opening 406 and can be coiled within a cable storage region about an exterior of the main spool 402. To pay the excess cable off the main spool 402, a mandrel is inserted through the central hollow post 404 and thus also through the mandrel opening 390. By pulling the first end 122 of the cable 120, the main spool 402 rotates about the mandrel thereby allowing the excess length of cable 120 to be paid off from the main spool 402. Once the excess length of cable 120 has been fully paid off from the main spool 402, the cassette 360 can be removed from the main spool 402. It be appreciated that multiple cassettes and multiple main spools can be stacked in coaxial alignment on the mandrel to facilitate simultaneous deployment of multiple cables.

[0099] FIGS. 53-55 depict an alternative arrangement where the spool 302 is mounted directly between removable supplemental spool flanges 410 between which excess cable length beyond the capacity of the spool 302 can be coiled. The flanges 410 410 can be removed from the spool 302 after deployment of the excess cable length. In certain examples, the flanges 410 can be made of material such as cardboard. As shownat FIGS. 56-57, in certain examples, multiple spools 302 can be stacked between a single pair of the flanges 410 such that the single pair of flanges provides containment of the excess fiber lengths of multiple spools 302. The flanges 410 can overlap axial end faces of the spool 302. A core structure 412 having retention end flanges 414 can extend through a core opening of the spool 302 and can be used to secure the supplemental flanges 410 to the axial ends of the spool 302. The core structure 412 can have first and second pieces that extend through the core opening and snap together such that the spool 302 and the supplemental flanges 410 are captured between the end flanges 414.

[0100] FIG. 58 illustrates an alternative arrangement of the main spool 402. The main spool 402 is formed from cardboard. The cassette 60, 360 may be packaged within the main spool 402. The cardboard material defines the side opening 406. The main spool 402 can have a general octagonal shape; however, other shapes are possible as well. The octagonal shape defines sides for retaining the spooled length of the cable 120.

[0101] The various examples described above are provided by way of illustration only and should not be construed to limit the scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example examples and applications illustrated and described herein, and without departing from the true spirit and scope of the present disclosure.Aspects of the DisclosureAspect 1. A telecommunication cassette adapted to be mounted within a telecommunication chassis, the telecommunication cassette comprising: a cassette body including a width that extends between opposite first and second sides of the cassette body, a depth that extends between opposite front and back ends of the cassette body and a height that extends between top and bottom sides of the cassette body; front fiber-optic adapters mounted adjacent the front end of the cassette body, the front fiber-optic adapters each including a front port facing in a forward direction and a rear port facing in a rearward direction;the cassette body defining a fiber routing region and a spool recess, the spool recess being located adjacent the back end of the cassette body and the fiber routing region being located between the spool recess and the front fiber optic adapters; the cassette body including a center reference line that extends in a forward / rearward orientation and that bisects the width of the cassette body; a spool that mounts within the spool recess, the spool being rotatable relative to the cassette body about a rotation axis that extends in an upward / downward orientation, the rotation axis being offset in a first offset direction from the center reference line; the cassette body defining a rear adapter mounting location adjacent the back end of the cassette body for mounting a rear fiber optic adapter, the rear adapter mounting location being offset in a second offset direction from the center reference line, the second offset direction being opposite from the first offset direction, the rear fiber optic adapter having a front port facing in the forward direction and a rear port facing in the rearward direction; and an optical cable wrapped about the spool, the optical cable having first and second opposite ends, wherein the optical cable can be dispensed from the spool by pulling on the first end of the optical cable causing the spool to rotate about the rotation axis relative to the cassette body as the optical cable is dispensed from the spool.Aspect 2. The telecommunication cassette of aspect 1, wherein the spool includes a spool core coaxially aligned with the rotation axis, wherein the spool also includes top and bottom spool flanges that project radially outwardly from the spool core, wherein the optical cable is wrapped about the spool core and is contained between the top and bottom spool flanges.Aspect 3. The telecommunication cassette of aspect 2, wherein the cassette body includes a recess-defining portion that defines the spool recess, the recess-defining portion including a bottom wall for opposing the bottom spool flange when the spool is mounted within the spool recess, the recess-defining portion also including a circumferential wall adapted to extend circumferentially about an outer periphery of at least a portion of at least one of the top and bottom spool flanges when the spool is mounted within the spool recess.Aspect 4. The telecommunication cassette of aspect 3, wherein the circumferential wall is configured to extend about a first circumferential portion of the top spool flange when the spool is mounted within the spool recess, wherein the circumferential wall is configured to extend about a second circumferential portion of the bottom spool flange when the spool is mounted within the spool recess, wherein the second circumferential portion is circumferentially longer than the first circumferential portion, and wherein the first circumferential portion extends for at least 200° about the rotation axis.Aspect 5. The telecommunication cassette of aspect 3, wherein the bottom wall includes a resilient latch movable between a retaining position and a release position, the resilient latch being unitary with the bottom wall and being biased toward the retaining position, the resilient latch being configured to prevent rotation of the spool relative to the cassette body when in the retaining position and being configured to allow rotation of the spool relative to the cassette body when in the release position.Aspect 6. The telecommunication cassette of aspect 1, wherein the spool includes a spool core and top and bottom spool flanges that project radially outwardly from the spool core, wherein at least one of the top and bottom spool flanges defines an outer cross dimension that is at least 60% as large as the width of the cassette body.Aspect 7. The telecommunication cassette of aspect 1, wherein the spool includes a spool core and top and bottom spool flanges that project radially outwardly from the spool core, wherein at least one of the top and bottom spool flanges defines an outer cross dimension that is at least 70% as large as the width of the cassette body.Aspect 8. The telecommunication cassette of aspect 1, wherein the spool includes a spool core and top and bottom spool flanges that project radially outwardly from the spool core, wherein at least one of the top and bottom spool flanges defines an outer cross dimension that is 60-90 percent as large as the width of the cassette body.Aspect 9. The telecommunication cassette of any of aspects 6-8, wherein the outer cross dimension is an outer diameter.Aspect 10. The telecommunication cassette of any of aspects 1-9, wherein the spool recess and the rear adapter mounting location occupy non-overlapping regions of the width of the cassette body.Aspect 11. The telecommunication cassette of aspect 1 , wherein the optical cable is a multi-fiber optical cable, wherein single-fiber optical connectors are loaded in the rear ports of the front fiber-optic adapters, wherein a first multi-fiber optical connector is loaded in the front port of the rear fiber-optic adapter, where an optical fiber is optically connect the single-fiber optical connectors to the first multi-fiber optical connector, wherein the optical fibers are routed through the fiber routing region of the cassette body, wherein second and third multi-fiber connectors are respectively attached to the first and second ends of the fiber optic cable, wherein the third multi-fiber connector is carried with and rotates in unison with the spool during dispensing of the optical cable from the spool, and where and after deployment of the optical cable the third multifiber connector is detached from the spool and secured within the rear port of the rear fiber-optic adapter.Aspect 12. The telecommunication cassette of aspect 2, wherein a fiber optic connector is attached to the second end of the optical cable, and wherein the fiber optic connector is carried within rotates in unison with the spool during dispensing of the optical cable from the spool, and where and after deployment of the optical cable of the fiber optic connector is detached from the spool and secured within the rear port of the rear fiber-optic adapter.Aspect 13. The telecommunication cassette of aspect 12, further comprising a connector holder that mounts in the spool core for holding the fiber optic connector during dispensing of the optical cable from the spool.Aspect 14. The telecommunication cassette of aspect 13, wherein the connector holder projects above the top side of the cassette body when mounted within the spool core such that the fiber optic connector is held at a location above the top side of the cassette body.Aspect 15. The telecommunication cassette of aspect 14, wherein the connector holder is removable from the spool after the optical cable has been dispensed from the spool.Aspect 16. The telecommunication cassette of aspect 15, wherein the connector holder holds the fiber optic connector by a first snap-fit connection, and is secured within the spool core by a second snap-fit connection.Aspect 17. The telecommunication cassette of aspect 3, wherein the spool core defines a connector storage recess and the spool includes an unitary connector holder within the connector storage recess for holding a connector attached at the second end of the cable during rotation of the spool within the spool recess.Aspect 18. The telecommunication cassette of aspect 17, wherein the connector storage recess is configured to store excess cable length and the spool includes cable retention fingers the project over the connector storage recess and cable management spool structures within the connector storage recess.Aspect 19. The telecommunication cassette of aspect 17, wherein the cassette body defines a rear cable dispensing opening in communication with the spool recess for dispensing the optical cable from the spool within the connector storage recess, and wherein the spool defines an open region that extends through the top flange and the spool core to the connector storage recess.Aspect 20. The telecommunication cassette of aspect 19, wherein the rear cable dispensing opening has rounded left and right ends, and wherein the cassette body includes channel defining fingers for guiding a portion of the cable corresponding to the second end of the cable from the rear cable dispensing opening to the rear fiber optic adapter.Aspect 21. The telecommunication opening of aspect 1 , wherein the cassette body defines a mandrel opening that extends through the height of the cassette body and that is offset from the spool recess.Aspect 22. A telecommunication cassette adapted to be mounted within a telecommunication chassis, the telecommunication cassette comprising: a cassette body including a width that extends between opposite first and second sides of the cassette body, a depth that extends between opposite front and back ends of the cassette body and a height that extends between top and bottom sides of the cassette body; front fiber-optic adapters mounted adjacent the front end of the cassette body, the front fiber-optic adapters each including a front port facing in a forward direction and a rear port facing in a rearward direction; a spool carried with the cassette body, the spool being rotatable relative to the cassette body about a rotation axis that extends in an upward / downward orientation, wherein the spool includes a spool core coaxially aligned with the rotation axis, wherein the spool also includes top and bottom spool flanges that project radially outwardly from the spool core; an optical cable wrapped about the spool core and contained between the top and bottom spool flanges, the optical cable having first and second opposite ends, wherein the optical cable can be dispensed from the spool by pulling on the first end of the optical cable causing the spool to rotate about the rotation axis relative to the cassette body as the optical cable is dispensed from the spool, and wherein a fiber optic connector is attached to the second end of the optical cable; a connector holder that detachably mounts within the spool core for holding the fiber optic connector such that the fiber optic connector rotates in unison with the spool about the rotation axis as the optical cable is dispensed from the spool, wherein the connector holder projects above the top side of the cassette body when mounted within the spool core and is configured for holding the fiber optic connector above the top spool flange.Aspect 23. The telecommunication cassette of aspect 22, wherein the connector holder holds the fiber optic connector by a first snap-fit connection, and is secured within the spool core by a second snap-fit connection.Aspect 24. The telecommunication cassette of aspect 22, wherein the top and bottom flanges of the spool are within a form factor defined by the height of the cassette body, and wherein the connector holder extends above the form factor of the height of the cassette body when secured within the spool core.Aspect 25. A telecommunication system comprising: a chassis configured to be secured to a telecommunication rack, the chassis including a main chassis body including a front end and a rear end, the chassis including side flanges adjacent the front end of the main chassis body for securing the chassis to a rack, the chassis including a rear cover that detachably mounts to the rear end of the main chassis body, the rear cover including a rear wall defining a vertical reference plane when the rear cover is mounted to the main chassis body, wherein the chassis further includes fiber management loops; first cassettes configured to be installed within the chassis and used in combination with the rear cover, wherein when the first cassettes are installed within the chassis, the first cassettes do not extend rearwardly beyond the vertical reference plane; and second cassettes configured to be mounted within the chassis and used with the rear cover removed, wherein the second cassettes include rotatable spools that can be rotated with respect to the second cassettes to allow optical cables to be dispensed from the second cassettes, and wherein the second cassettes are installed within chassis portions of the rotatable spools and project rearwardly beyond the vertical reference plane.Aspect 26. The telecommunication system of aspect 25, wherein the main chassis body includes a first connection arrangement that interfaces with a second connection arrangement of the rear cover to secure the rear cover to the main chassis body, and wherein when the second cassettes are installed within the chassis, fiber management loops can be secured to the main chassis body through engagement with the first connection arrangement.Aspect 27. A telecommunication system comprising: a chassis configured to be secured to a telecommunication rack, the chassis including a main chassis body including a front end and a rear end, the chassis including side flanges adjacent the front end of the main chassis body for securing the chassis to a rack, the chassis including a rear cover that detachably mounts to the rear end of the main chassis body, the rear cover including a rear wall defining a vertical reference plane when the rear cover is mounted to the main chassis body; first cassettes configured to be installed within the chassis and used in combination with the rear cover, wherein when the first cassettes are installed within the chassis, the first cassettes do not extend rearwardly beyond the vertical reference plane; and second cassettes configured to be mounted within the chassis and used with the rear cover replaced by an extension assembly, wherein the second cassettes include rotatable spools that can be rotated with respect to the second cassettes to allow optical cables to be dispensed from the second cassettes, wherein the second cassettes are installed within chassis portions of the rotatable spools which project rearwardly beyond the vertical reference plane, wherein the extension assembly mounts to the rear end of the main chassis body, wherein the extension assembly includes side opening for routing cable laterally from the chassis, and wherein the extension includes a rear panel that can be pivoted to a closed position covering rear ends of the second cassettes when the second cassettes are mounted in the chassis.Aspect 28. An extension assembly adapted to be mounted to a rear end of a chassis, the extension assembly comprising: extension bodies having front ends and rear ends, the extension bodies defining cable routing openings; first connectors for connecting the front ends of the extension bodies of the extension assembly to the rear end of the chassis; a pivotal rear cover panel assembly; and second connectors for connecting the rear ends of the extension bodies to the pivotal rear cover panel assembly.Aspect 29. A telecommunication cassette adapted to be mounted within a telecommunication chassis, the telecommunication cassette comprising: a cassette body including a width that extends between opposite first and second sides of the cassette body, a depth that extends between opposite front and back ends of the cassette body and a height that extends between top and bottom sides of the cassette body; front fiber-optic adapters mounted adjacent the front end of the cassette body, the front fiber-optic adapters each including a front port facing in a forward direction and a rear port facing in a rearward direction; a cassette spool carried with the cassette body, the cassette spool being rotatable relative to the cassette body about a rotation axis that extends in an upward / downward orientation, wherein the cassette spool includes a spool core coaxially aligned with the rotation axis, wherein the cassette spool also includes top and bottom spool flanges that project radially outwardly from the spool core; and a main spool for coiling excess cable beyond a storage capacity of the cassette spool, the main spool having an axial end face at which the cassette spool can be positioned, the main spool having a hollow axial post that fits within an opening defined by the cassette body that is offset from the spool recess.

Claims

What is claimed is:

1. A telecommunication cassette adapted to be mounted within a telecommunication chassis, the telecommunication cassette comprising: a cassette body including a width that extends between opposite first and second sides of the cassette body, a depth that extends between opposite front and back ends of the cassette body and a height that extends between top and bottom sides of the cassette body; front fiber-optic adapters mounted adjacent the front end of the cassette body, the front fiber-optic adapters each including a front port facing in a forward direction and a rear port facing in a rearward direction; the cassette body defining a fiber routing region and a spool recess, the spool recess being located adjacent the back end of the cassette body and the fiber routing region being located between the spool recess and the front fiber optic adapters; the cassette body including a center reference line that extends in a forward / rearward orientation and that bisects the width of the cassette body; a spool that mounts within the spool recess, the spool being rotatable relative to the cassette body about a rotation axis that extends in an upward / downward orientation, the rotation axis being offset in a first offset direction from the center reference line; the cassette body defining a rear adapter mounting location adjacent the back end of the cassette body for mounting a rear fiber optic adapter, the rear adapter mounting location being offset in a second offset direction from the center reference line, the second offset direction being opposite from the first offset direction, the rear fiber optic adapter having a front port facing in the forward direction and a rear port facing in the rearward direction; and an optical cable wrapped about the spool, the optical cable having first and second opposite ends, wherein the optical cable can be dispensed from the spool by pulling on the first end of the optical cable causing the spool to rotate about the rotation axis relative to the cassette body as the optical cable is dispensed from the spool.

2. The telecommunication cassette of claim 1, wherein the spool includes a spool core coaxially aligned with the rotation axis, wherein the spool also includes top and bottom spool flanges that project radially outwardly from the spool core, wherein the optical cable is wrapped about the spool core and is contained between the top and bottom spool flanges.

3. The telecommunication cassette of claim 2, wherein the cassette body includes a recess-defining portion that defines the spool recess, the recess-defining portion including a bottom wall for opposing the bottom spool flange when the spool is mounted within the spool recess, the recess-defining portion also including a circumferential wall adapted to extend circumferentially about an outer periphery of at least a portion of at least one of the top and bottom spool flanges when the spool is mounted within the spool recess.

4. The telecommunication cassette of claim 3, wherein the circumferential wall is configured to extend about a first circumferential portion of the top spool flange when the spool is mounted within the spool recess, wherein the circumferential wall is configured to extend about a second circumferential portion of the bottom spool flange when the spool is mounted within the spool recess, wherein the second circumferential portion is circumferentially longer than the first circumferential portion, and wherein the first circumferential portion extends for at least 200° about the rotation axis.

5. The telecommunication cassette of claim 3, wherein the bottom wall includes a resilient latch movable between a retaining position and a release position, the resilient latch being unitary with the bottom wall and being biased toward the retaining position, the resilient latch being configured to prevent rotation of the spool relative to the cassette body when in the retaining position and being configured to allow rotation of the spool relative to the cassette body when in the release position.

6. The telecommunication cassette of claim 1, wherein the spool includes a spool core and top and bottom spool flanges that project radially outwardly from the spoolcore, wherein at least one of the top and bottom spool flanges defines an outer cross dimension that is at least 60% as large as the width of the cassette body.

7. The telecommunication cassette of claim 1, wherein the spool includes a spool core and top and bottom spool flanges that project radially outwardly from the spool core, wherein at least one of the top and bottom spool flanges defines an outer cross dimension that is at least 70% as large as the width of the cassette body.

8. The telecommunication cassette of claim 1, wherein the spool includes a spool core and top and bottom spool flanges that project radially outwardly from the spool core, wherein at least one of the top and bottom spool flanges defines an outer cross dimension that is 60-90 percent as large as the width of the cassette body.

9. The telecommunication cassette of any of claims 6-8, wherein the outer cross dimension is an outer diameter.

10. The telecommunication cassette of any of claims 1-9, wherein the spool recess and the rear adapter mounting location occupy non-overlapping regions of the width of the cassette body.

11. The telecommunication cassette of claim 1 , wherein the optical cable is a multifiber optical cable, wherein single-fiber optical connectors are loaded in the rear ports of the front fiber-optic adapters, wherein a first multi-fiber optical connector is loaded in the front port of the rear fiber-optic adapter, where an optical fiber is optically connect the single-fiber optical connectors to the first multi-fiber optical connector, wherein the optical fibers are routed through the fiber routing region of the cassette body, wherein second and third multi-fiber connectors are respectively attached to the first and second ends of the fiber optic cable, wherein the third multi-fiber connector is carried with and rotates in unison with the spool during dispensing of the optical cable from the spool, and where and after deployment of the optical cable the third multi-fiber connector is detached from the spool and secured within the rear port of the rear fiber-optic adapter.

12. The telecommunication cassette of claim 2, wherein a fiber optic connector is attached to the second end of the optical cable, and wherein the fiber optic connector is carried within rotates in unison with the spool during dispensing of the optical cable from the spool, and where and after deployment of the optical cable of the fiber optic connector is detached from the spool and secured within the rear port of the rear fiberoptic adapter.

13. The telecommunication cassette of claim 12, further comprising a connector holder that mounts in the spool core for holding the fiber optic connector during dispensing of the optical cable from the spool.

14. The telecommunication cassette of claim 13, wherein the connector holder projects above the top side of the cassette body when mounted within the spool core such that the fiber optic connector is held at a location above the top side of the cassette body.

15. The telecommunication cassette of claim 14, wherein the connector holder is removable from the spool after the optical cable has been dispensed from the spool.

16. The telecommunication cassette of claim 15, wherein the connector holder holds the fiber optic connector by a first snap-fit connection, and is secured within the spool core by a second snap-fit connection.

17. The telecommunication cassette of claim 3, wherein the spool core defines a connector storage recess and the spool includes an unitary connector holder within the connector storage recess for holding a connector attached at the second end of the cable during rotation of the spool within the spool recess.

18. The telecommunication cassette of claim 17, wherein the connector storage recess is configured to store excess cable length and the spool includes cable retention fingers the project over the connector storage recess and cable management spool structures within the connector storage recess.

19. The telecommunication cassette of claim 17, wherein the cassette body defines a rear cable dispensing opening in communication with the spool recess for dispensing the optical cable from the spool within the connector storage recess, and wherein the spool defines an open region that extends through the top flange and the spool core to the connector storage recess.

20. The telecommunication cassette of claim 19, wherein the rear cable dispensing opening has rounded left and right ends, and wherein the cassette body includes channel defining fingers for guiding a portion of the cable corresponding to the second end of the cable from the rear cable dispensing opening to the rear fiber optic adapter.

21. The telecommunication opening of claim 1 , wherein the cassette body defines a mandrel opening that extends through the height of the cassette body and that is offset from the spool recess.

22. A telecommunication cassette adapted to be mounted within a telecommunication chassis, the telecommunication cassette comprising: a cassette body including a width that extends between opposite first and second sides of the cassette body, a depth that extends between opposite front and back ends of the cassette body and a height that extends between top and bottom sides of the cassette body; front fiber-optic adapters mounted adjacent the front end of the cassette body, the front fiber-optic adapters each including a front port facing in a forward direction and a rear port facing in a rearward direction; a spool carried with the cassette body, the spool being rotatable relative to the cassette body about a rotation axis that extends in an upward / downward orientation,wherein the spool includes a spool core coaxially aligned with the rotation axis, wherein the spool also includes top and bottom spool flanges that project radially outwardly from the spool core; an optical cable wrapped about the spool core and contained between the top and bottom spool flanges, the optical cable having first and second opposite ends, wherein the optical cable can be dispensed from the spool by pulling on the first end of the optical cable causing the spool to rotate about the rotation axis relative to the cassette body as the optical cable is dispensed from the spool, and wherein a fiber optic connector is attached to the second end of the optical cable; a connector holder that detachably mounts within the spool core for holding the fiber optic connector such that the fiber optic connector rotates in unison with the spool about the rotation axis as the optical cable is dispensed from the spool, wherein the connector holder projects above the top side of the cassette body when mounted within the spool core and is configured for holding the fiber optic connector above the top spool flange.

23. The telecommunication cassette of claim 22, wherein the connector holder holds the fiber optic connector by a first snap-fit connection, and is secured within the spool core by a second snap-fit connection.

24. The telecommunication cassette of claim 22, wherein the top and bottom flanges of the spool are within a form factor defined by the height of the cassette body, and wherein the connector holder extends above the form factor of the height of the cassette body when secured within the spool core.

25. A telecommunication system comprising: a chassis configured to be secured to a telecommunication rack, the chassis including a main chassis body including a front end and a rear end, the chassis including side flanges adjacent the front end of the main chassis body for securing the chassis to a rack, the chassis including a rear cover that detachably mounts to the rear end of the main chassis body, the rear cover including a rear wall defining a verticalreference plane when the rear cover is mounted to the main chassis body, wherein the chassis further includes fiber management loops; first cassettes configured to be installed within the chassis and used in combination with the rear cover, wherein when the first cassettes are installed within the chassis, the first cassettes do not extend rearwardly beyond the vertical reference plane; and second cassettes configured to be mounted within the chassis and used with the rear cover removed, wherein the second cassettes include rotatable spools that can be rotated with respect to the second cassettes to allow optical cables to be dispensed from the second cassettes, and wherein the second cassettes are installed within chassis portions of the rotatable spools and project rearwardly beyond the vertical reference plane.

26. The telecommunication system of claim 25, wherein the main chassis body includes a first connection arrangement that interfaces with a second connection arrangement of the rear cover to secure the rear cover to the main chassis body, and wherein when the second cassettes are installed within the chassis, fiber management loops can be secured to the main chassis body through engagement with the first connection arrangement.

27. A telecommunication system comprising: a chassis configured to be secured to a telecommunication rack, the chassis including a main chassis body including a front end and a rear end, the chassis including side flanges adjacent the front end of the main chassis body for securing the chassis to a rack, the chassis including a rear cover that detachably mounts to the rear end of the main chassis body, the rear cover including a rear wall defining a vertical reference plane when the rear cover is mounted to the main chassis body; first cassettes configured to be installed within the chassis and used in combination with the rear cover, wherein when the first cassettes are installed within the chassis, the first cassettes do not extend rearwardly beyond the vertical reference plane; andsecond cassetes configured to be mounted within the chassis and used with the rear cover replaced by an extension assembly, wherein the second cassetes include rotatable spools that can be rotated with respect to the second cassetes to allow optical cables to be dispensed from the second cassetes, wherein the second cassetes are installed within chassis portions of the rotatable spools which project rearwardly beyond the vertical reference plane, wherein the extension assembly mounts to the rear end of the main chassis body, wherein the extension assembly includes side opening for routing cable laterally from the chassis, and wherein the extension includes a rear panel that can be pivoted to a closed position covering rear ends of the second cassetes when the second cassetes are mounted in the chassis.

28. An extension assembly adapted to be mounted to a rear end of a chassis, the extension assembly comprising: extension bodies having front ends and rear ends, the extension bodies defining cable routing openings; first connectors for connecting the front ends of the extension bodies of the extension assembly to the rear end of the chassis; a pivotal rear cover panel assembly; and second connectors for connecting the rear ends of the extension bodies to the pivotal rear cover panel assembly.

29. A telecommunication cassete adapted to be mounted within a telecommunication chassis, the telecommunication cassete comprising: a cassete body including a width that extends between opposite first and second sides of the cassete body, a depth that extends between opposite front and back ends of the cassete body and a height that extends between top and botom sides of the cassete body; front fiber-optic adapters mounted adjacent the front end of the cassete body, the front fiber-optic adapters each including a front port facing in a forward direction and a rear port facing in a rearward direction;a cassete spool carried with the cassette body, the cassette spool being rotatable relative to the cassete body about a rotation axis that extends in an upward / downward orientation, wherein the cassete spool includes a spool core coaxially aligned with the rotation axis, wherein the cassete spool also includes top and botom spool flanges that project radially outwardly from the spool core; and a main spool for coiling excess cable beyond a storage capacity of the cassete spool, the main spool having an axial end face at which the cassete spool can be positioned, the main spool having a hollow axial post that fits within an opening defined by the cassete body that is offset from the spool recess.

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