Telecommunications chassis and module

A telecommunications system (14) includes a chassis (12) defining a front (18), a rear (16), and a plurality of first signal connection locations (38) adjacent the rear (16). A plurality of removable cassettes (10) are housed within the chassis (12), each including a cassette body (68) defining a fixed portion (80) that is coupled to one of the first signal connection locations (38) on the chassis (12) and a movable portion (82) that telescopically slides relative to the fixed portion (80), wherein the movable portion (82) is configured for movement in a direction from the front (18) to the rear (16) of the chassis (12), each cassette (10) defining a plurality of second signal connection locations (58). A cable (24) between the fixed portion (80) and the movable portion (82) extends out from the movable portion (82) when that portion (82) is pulled forwardly to an extended position and is retracted into the cassette body (68) when the movable portion (82) is pushed rearwardly relative to the fixed portion (80).

BACKGROUND

As demand for telecommunications services increases, fiber optic networks are being extended in more and more areas. Management of the cables, ease of installation, and ease of accessibility for later management are important concerns. As a result, there is a need for fiber optic devices which address these and other concerns.

SUMMARY

An aspect of the present disclosure relates to fiber optic devices in the form of fiber optic cassettes and chassis for housing such cassettes, wherein each cassette includes at least one connector that provides a signal entry location and at least one connector that provides a signal exit location. A ribbon cable extending from the at least one connector at the signal entry location toward the at least one connector at the signal exit location is managed internally within the body of the cassette.

In certain embodiments, the cassette includes a fixed portion that is optically coupled to a backplane of a telecommunications chassis. The cassette further includes a telescopically movable portion that moves together with trays/blades that are slidable on the chassis, wherein the trays/blades support the cassettes. The ribbon cable that includes optical fibers for relaying fiber optic signals from the fixed portion of the cassette to the movable portion of the cassette extends out of the cassette body when the movable portion of the cassette is telescopically pulled out (via the trays/blades). The ribbon cable retracts into the cassette body and is managed internally via spools within the interior of the cassette body when the movable portion is moved back into the chassis via the trays/blades. The chassis, along with the cassettes housed within the chassis, form a part of the telecommunications system of the present disclosure.

According to another aspect of the present disclosure, a telecommunications system comprises a chassis defining a front, a rear, and a plurality of first signal connection locations provided adjacent the rear, a plurality of removable cassettes housed within the chassis, each cassette including a cassette body defining a fixed portion that is coupled to one of the first signal connection locations provided on the chassis and a movable portion that telescopically slides with respect to the fixed portion, wherein the movable portion of the cassette is configured for movement in a direction extending from the front to the rear of the chassis, wherein each cassette defines a plurality of second signal connection locations, and wherein a cable extending between the fixed portion and the movable portion extends out from the movable portion when the movable portion is pulled forwardly to an extended position and the cable is retracted into and managed internally within the cassette body when the movable portion is pushed rearwardly with respect to the fixed portion.

According to another aspect of the present disclosure, a fiber optic cassette comprises a cassette body defining a fixed portion that is configured to be fixedly coupled to a telecommunications chassis, wherein the fixed portion defines a fiber optic connector for optically mating with a fiber optic adapter of the chassis, a movable portion that telescopically slides with respect to the fixed portion, and a plurality of fiber optic connection locations defined on the movable portion of the cassette body, wherein a cable extending from the fiber optic connector at the fixed portion toward the movable portion extends out from the movable portion when the movable portion is pulled away from the fixed portion, and the cable is retracted into and managed internally within the cassette body when the movable portion and the fixed portion are brought together.

According to another aspect of the present disclosure, a fiber optic cassette comprises a cassette body defining a fixed portion that is configured to be fixedly coupled to a telecommunications chassis, wherein the fixed portion defines a fiber optic connector for optically mating with a fiber optic adapter of the chassis and a movable portion that telescopically slides with respect to the fixed portion, a plurality of fiber optic adapters defined on the movable portion of the body, wherein a ribbon cable extending from the fiber optic connector at the fixed portion toward the movable portion extends out from the movable portion when the movable portion is pulled away from the fixed portion, and the ribbon cable is retracted into and managed internally within the cassette body when the movable portion and the fixed portion are brought together, wherein the ribbon cable carries a plurality of fibers that extend to the fiber optic adapters defined on the movable portion of the cassette body, wherein the cassette includes a transition fiber array defined by a polymeric substrate that supports the plurality of fibers extending from the ribbon cable toward the fiber optic adapters of the movable portion of the cassette body, the fiber optic adapters each configured to mate a standard fiber optic connector to a non-conventional fiber optic connector that is terminated to one of the fibers extending from the ribbon cable and supported by the polymeric substrate.

According to another aspect of the present disclosure, a method of managing a cable extending from a fiber optic connection location provided on a chassis toward a fiber optic cassette that is slidable within the chassis comprises moving the fiber optic cassette toward an extended position away from the chassis to expose the cable, and moving the fiber optic cassette toward a retracted position in the chassis and automatically spooling the cable within the fiber optic cassette as the fiber optic cassette is moved.

According to yet another aspect of the present disclosure, a telecommunications system comprises a chassis defining a front, a rear, and a plurality of first signal connection locations, a plurality of cassettes housed within the chassis, at least a portion of each cassette slidably movable in a direction extending from the front to the rear of the chassis, wherein each cassette defines a plurality of second signal connection locations, and wherein a cable extending between one of the first signal connection locations of the chassis and the movable portion of the cassette extends out from the movable portion when the movable portion is pulled forwardly to an extended position, and the cable is retracted into and managed internally within the cassette when the movable portion is pushed rearwardly to a retracted position.

DETAILED DESCRIPTION

The present disclosure is directed generally to fiber optic devices in the form of fiber optic cassettes10and telecommunications chassis12configured to house such fiber optic cassettes10, wherein the chassis12and the cassettes10form a part of a telecommunications system14of the present disclosure. The cassettes10may be removable, replaceable, modular units.

As will be described in further detail below, the fiber optic cassettes10of the present disclosure are designed to relay signals input adjacent a rear16of the chassis12toward connection locations adjacent a front18of the chassis12for further distribution.

Each cassette10houses and directs multiple fibers which terminate at a rear connector92, such as an MPO style connector, to a plurality of adapters58positioned at a generally front portion of the cassette10. The fiber optic cassettes10of the present disclosure are designed to internally manage the cabling24carrying the fibers as trays/blades26supporting the cassettes10move between an extended position and a retracted position.

According to certain embodiments, the fiber optic cassettes10of the present disclosure provide a transition housing or support between multi-fibered connectors, such as MPO style connectors having MT ferrules, and single or dual fiber connectors, such as LC or SC type connectors, wherein that transition housing or support includes features for internally managing cabling24as the cassettes10move between the extended and retracted positions.

Referring now toFIGS. 1-2, a fiber optic telecommunications system14having features that are examples of inventive aspects in accordance with the present disclosure is illustrated. The system14includes a telecommunications chassis or panel12configured to be mounted on a telecommunications rack. In the depicted embodiment, the chassis12is sized to be mountable on a standard 19-inch telecommunications rack.

According to the depicted embodiment, the chassis12is defined by a right wall28and a left wall30. The right and left walls28,30define mounting flanges32adjacent a front18of the chassis12for mounting the chassis12to a telecommunications rack.

Adjacent a rear16of the chassis12, a back wall34extends between the right and left walls28,30of the chassis12. The back wall34defines a fiber optic backplane36consisting of a plurality of fiber optic adapters38arranged in parallel rows and columns. In the depicted embodiment, the backplane36defines MPO style fiber optic adapters38that are configured to receive and couple MPO style fiber optic connectors. Each of the cassettes10supported by the trays26of the chassis12are configured to be optically coupled to the backplane36for receiving input signals.

Still referring toFIGS. 1-2, in the depicted embodiment of the chassis12, a pair of cable management structures40in the form of cable rings are provided at the front18of the chassis12at each of the right and left walls28,30. The cable rings40are configured to manage cables leading to or away from the optical cassettes10that are housed within the chassis12. Further details relating to cable management structures similar to cable rings40are described and illustrated in International Publication No. WO 2015/040211, the entire disclosure of which is incorporated herein by reference.

A front door42of the chassis12extends between the right and left walls28,30and is pivotally opened to provide access to the connection locations defined by the optical cassettes10within the chassis12. Further details relating to the door42and a hinge arrangement that allows the door42to be movable between a fully closed position and a fully open position that is at 180 degrees from the fully closed position are described and illustrated in International Publication No. WO 2016/012295, the entire disclosure of which is incorporated herein by reference. The hinge mechanism44of the door42allows the door to be fully opened, enabling extension or removal of the pull-out trays/blades26housed within the chassis12.

Still referring toFIGS. 1-2, in the depicted embodiment, the chassis12is configured to have a height of two standard rack units (2RU). Other heights are possible. Within the 2RU height, the chassis12is configured to house eight blades or trays26that are mounted in a vertically stacked arrangement within the chassis12. One of the blades26(populated with the cassettes10of the present disclosure) is shown in isolation inFIGS. 3-4.

As shown, each blade26defines a generally planar configuration with slide portions46defined at each of the right and left sides48,50of the blade26. And, as shown inFIGS. 1-2, at each of the right and left walls28,30, the chassis12defines mounting slots52for receiving the slide portions46of the blades26. The slide portions46of the blades26and the mounting slots52of the chassis walls28,30are configured to cooperate such that positive stops are provided for predetermined positions of the blades26with respect to the chassis12. For example, a positive stop may be provided when the blade26is at a neutral (retracted) position within the chassis12. Once the blade26is pulled out by a user toward an extended position, another positive stop may be provided at the fully extended position to keep the blade26coupled to the chassis12. If the blade26needs to be fully removed from the chassis12, the slide portions46of the blade26may be flexed inwardly to remove tabs defined by the slide portions46from notches defined within the mounting slots52of the chassis12, and the blade26pulled out.

Further details relating to the slide mechanism provided between the chassis12and the individual trays/blades26and the operation thereof is described and illustrated in International Publication No. WO 2015/040211, the entire disclosure of which has been incorporated herein by reference.

As noted above, in the depicted telecommunications system14, the blades/trays26of the chassis12are used for supporting telecommunications devices in the form of fiber optic cassettes10that are for relaying fiber optic signals. Cable management devices54may be positioned between each of the cassettes10for managing cables extending from the front sides60of the cassettes10. In the depicted embodiment, each tray/blade26is sized to hold five fiber optic cassettes10along a row within the 19-inch standard rack spacing. One example of a cassette10that is configured for mounting on the chassis12is shown in isolation inFIGS. 5-9, further details of which will be described below.

According to one example embodiment, the depicted cassette10is configured to provide twelve connection locations58defined by standard LC format adapters at the front60of the cassette10, as will be discussed in further detail below. The LC adapters58may be formed as part of an adapter block62. With five cassettes10located on each blade26, and with eight blades26located on each chassis12, the chassis12can accommodate a density of 480 standard LC format connections within a 2RU rack spacing. A similar 1RU chassis12can, thus, accommodate 240 standard LC format connections within that 1RU spacing. Although, the density noted provides the maximum capacity for the system14, other connection location numbers may be utilized on the chassis12. For example, in other embodiments, the chassis12may utilize 180 standard LC format connections within a 1RU space. In yet other embodiments, the chassis may utilize 210 standard LC format connections within a 1RU space if the chassis is large enough to have a 2RU or greater capacity.

Now referring specifically toFIGS. 5 and 6, the blades26and the cassettes10are configured such that portions (e.g., at the bottom) of the cassettes10are configured to receive portions of the blades26to decrease the overall thickness of the mounted unit. Each cassette10defines a notched area64that extends a majority of the length of the cassette10, essentially from where the adapter block62is positioned to the rear66of the cassette10. As such, according to one example embodiment, when a cassette10is mounted on a blade26, the blade26lies flush with the cassette body68, and the thickness of the blade26is accommodated by the notched area64. As such, when a cassette10is mounted on the blade26, the cassette10can abut and lie against the blade26without substantially adding to the overall thickness of the unit. According to one example embodiment, the entire thickness of the blade26is accommodated by the notched area64. According to another example embodiment, at least a portion of the thickness of the blade26is accommodated by the notched area64. According to yet another example embodiment, at least a portion of the notched area64is used in accommodating the thickness of the blade26such that the blade body does not add to the maximum overall height of the cassette10.

As noted above, this configuration allows four cassette-loaded blades26to be mounted in a vertical stack in a 1RU rack space and eight cassette-loaded blades26to be mounted in a vertical stack in a 2RU rack space.

The cable managers54, discussed above, located between each fiber optic cassette10, help preserve the high density provided by the system14. As depicted, each cable manager54defines wider portions70at the front ends72thereof that transition to a rear section74having a thinner profile. The wider portions70define split-ring configurations for receiving and retaining cables extending to and from the cassettes10. The thinner profile sections74are positioned between the cassettes10when the cable managers54are mounted to the blades26to preserve the overall density within a 19-inch rack.

The thin portions74of the cable managers54allow five cassettes10, each holding up to twelve connections, to be mounted on blades26along a horizontal stack within the width defined by a standard 19-inch telecommunications rack. And, with four cassette-loaded blades26mounted in a vertical stack in a 1RU rack space, the system14of the present disclosure achieves significant connectivity densities.

As previously noted, according to one example embodiment, a maximum capacity of 480 connections each using a standard LC connector footprint are achieved in a standard 19-inch telecommunications rack within a 2RU rack space. According to another example embodiment, a maximum capacity of 240 connections each using a standard LC connector footprint are achieved in a standard 19-inch telecommunications rack within a 1RU rack space, as noted above.

The removability of the cassettes10provides significant flexibility in configuring the connectivity of system14as desired. For example, the blades26may be populated and the cassettes10arranged differently depending upon the densities needed and the different types and sizes of cabling used (e.g., 12 fiber 10-gig cabling, 24 fiber 40-gig cabling, or 48 fiber 100-gig cabling).

The removability of the cassettes10and the blades26of the systems14of the present disclosure allows different arrangements to be provided depending upon the connectivity need. Cassettes10can be added for increasing connectivity, removed for decreasing connectivity, or replaced if needing repair. The connection locations can be varied both in number and type. For example, the types of optical equipment (e.g., the types of cassettes10) can be varied within each blade26or within the different levels within a chassis12. Certain mounting locations of the blades26can be left unpopulated and used for other purposes such as labeling, etc.

Now referring toFIGS. 5-9in general, the parts that make up the body68of one example cassette10having inventive aspects in accordance with the present disclosure are shown. The cassette body68is defined by a base76and a cover78. The cassette body68defines a rear end66and a front end60. As shown, an adapter block62is positioned at the front end60of the body68. The adapter block62may be formed as an integral part of the base76, or may be provided as a removable structure that is captured thereagainst by the cover78. Similar fiber optic adapter blocks62, including those that might have staggered adapter configurations, are described and illustrated in further detail in U.S. Pat. No. 9,075,203, which patent is incorporated herein by reference in its entirety.

The base76of the cassette body68, as will be described in further detail below, defines a fixed portion80and a movable portion82that is configured to telescopically slide with respect to the fixed portion80. The two portions80,82of the base76facilitate management of the cable24that is carrying the fibers supported by the cassette10. A pair of slide rods84are provided for guiding and supporting the slidably movable portion82with respect to the fixed portion80.

As shown inFIGS. 5-9, the slide rods84extend through both the fixed portion80and the movable portion82of the base76of the cassette body68. The slide rods84are configured such that they may also be slidable with respect to the base76of the cassette body68. Each slide rod84defines a stop flange86at a rear end88thereof that can interact with the fixed portion80of the base76to prevent removal of the slide rod84from the fixed portion80. When the movable portion82of the base76starts to telescopically slide with respect to the fixed portion80, the slide rod84may also slidably move until the stop flange86abuts the fixed portion80of the base76, at which point, the movable portion82starts sliding with respect to the rod84.

According to certain embodiments, portions of the cassette body68may be formed from polymeric materials. The slide rods84may be formed from a metallic material for further rigidity.

The fixed portion80, as will be described in further detail below, defines a fiber optic adapter90(e.g., in the form of an MPO style adapter) at the rear end66of the cassette body68. A fiber optic connector92(in the form of an MPO connector) extends rearwardly from the MPO style adapter90. The fiber optic connector92is configured for coupling to the adapters38provided at the backplane36of the chassis12for inputting signals into the cassettes10.

The movable portions82of the cassette bodies68are coupled to and supported by the blades26of the chassis12and are configured to move with those blades26. As such, when the fixed portion80of each cassette10is physically and optically coupled to the backplane36defined by the chassis12, the movable portion82moves with the trays/blades26as the blades/trays26are pulled out from the chassis12.

Still referring toFIGS. 5-9, the fiber optic connector92extending rearward from the cassette10provides a signal entry location for the cassette10. And, the individual connector ports defined by the adapters58of the adapter block62at the front60of the cassette10provide signal exit locations.

A ribbon cable24terminated to and extending from the connector92at the signal entry location includes a plurality of fibers that carry signals being relayed toward the adapters58at the front60of the cassette10. The cassette10is configured such that the ribbon cable24moves from a position where it extends out of the cassette body68when the movable portion82of the base76has been telescopically pulled out (shown inFIGS. 8-9) to a retracted and managed position when the movable portion82has been retracted back to the neutral position (shown inFIG. 7). The ribbon cable24enters the movable portion82of the base76through an opening94adjacent the rear end99of the movable portion82. Once the ribbon cable24enters the movable portion82, it is guided toward (with bend radius protection) and managed internally via spools96,98within the interior100defined by the base76. When the movable portion82is retracted via the trays/blades26, the ribbon cable24can coil and be managed within the interior100defined by the movable portion82of the base76.

As shown inFIGS. 7-9, the base76defines a large spool96surrounding a small spool98for management of the ribbon cable24. The purpose of the two spools96,98will be described in further detail below.

Still referring toFIGS. 5-9, according to certain example embodiments, as shown in the depicted cassette10, within an interior100defined by the cassette body68, the cassette10may utilize a transitional fiber array102. According to certain embodiments, such a transitional fiber array102may or may not include a flexible substrate forming a flexible optical circuit for the transition of the fibers. In the depicted embodiment, the fiber array102is configured to branch out the fibers of the ribbon cable24and relay the fibers toward the adapters58positioned at the front60of the cassette10.

InFIGS. 7-9, the fiber array102is shown as being supported by a rigid polymeric insert104that has been placed within the base76of the cassette body68. Further details relating to the polymeric insert104and the method for manufacturing thereof are described and illustrated in U.S. Patent Publication No. 2016/0041357, the entire disclosure of which is incorporated herein by reference.

A rigid insert104, as the one shown inFIGS. 7-9, may define individual channels at a front end of the insert104where fibers can transition to a fiber consolidation point106at a rear end108of the insert104. The channels may define curved rear portions. The curvature of the channels may be designed to protect the minimum bend radius requirements of the fibers as the fibers extend rearwardly from the front end110to the rear end108of the insert104. At the fiber consolidation point106at the rear end108of the insert104, the fiber optic array102may define a clamp for clamping the consolidated fibers. The fiber clamp may be configured to keep the consolidated fibers in a given arrangement as they transition between the ribbon cable24and the branched fiber array102.

As noted above, the polymeric insert104, rather than being provided as a rigid structure, may also be replaced with a flexible substrate to provide a flexible optical circuit. Flexible optical circuits are passive optical components that comprise one or more (typically, multiple) optical fibers embedded on a flexible substrate, such as a Mylar™ material or other flexible polymer substrate. Commonly, although not necessarily, one end face of each fiber is disposed adjacent one longitudinal end of the flexible optical circuit substrate, and the other end face of each fiber is disposed adjacent the opposite longitudinal end of the flexible optical circuit substrate. The fibers extend past the longitudinal ends of the flexible optical circuit (commonly referred to as pigtails) so that they can be terminated to optical connectors, which can be coupled to fiber optic cables or other fiber optic components through mating optical connectors.

Flexible optical circuits essentially comprise one or more fibers sandwiched between two flexible sheets of material, such as Mylar™ material or another polymer. An epoxy may be included between the two sheets in order to adhere them together. Alternately, depending on the sheet material and other factors, the two sheets may be heated above their melting point to heat-weld them together with the fibers embedded between the two sheets.

In the depicted embodiment of the cassette10, even though the fiber array102is shown to be supported by a rigid polymeric insert104, in other embodiments, the cassette10may utilize a flexible circuit defined by a flexible substrate. Further details relating to cassettes utilizing flexible optical circuits are described and illustrated in WO 2014/052441 and WO 2014/052446, the entire disclosures of which are incorporated herein by reference.

The use of flexible optical circuits within the fiber optic cassettes10of the present disclosure may provide certain advantages. For example, the substrate of a flexible optical circuit may be mechanically flexible, being able to accommodate tolerance variations in different cassettes10, such as between connector ferrules and the housings that form the cassettes10. The flexibility of the optical circuits also allow for axial movement in the fibers to account for ferrule interface variation. Also, providing a supportive substrate104, either rigid or flexible, within which the fibers are positionally fixed, allows a designer to optimize the fiber bend radius limits and requirements in configuring the cassettes10, thus, achieving reduced dimensions of the cassettes10. The bend radius of the fibers can thus be controlled to a minimum diameter. By utilizing optical fibers such as bend insensitive fibers (e.g., 8 mm bend radius) in combination with a rigid insert104or a flexible substrate that fixes the fibers in a given orientation, allowing for controlled bending, small form cassettes10may be produced in a predictable and automated manner. Manual handling and positioning of the fibers within the cassettes10may be reduced and eliminated through the use of such fiber arrays102.

According to one example embodiment, in the fiber optic cassette10of the present disclosure, the fiber array102is provided between the ribbon cable24and the adapter block62located at the front60of the cassette10. The array102separates and relays the individual fibers of the ribbon cable24toward the adapter block62. As discussed in WO 2014/052441, WO 2014/052446, and U.S. Patent Publication No. 2016/0041357, the entire disclosures of which have been incorporated herein by reference, the array102can be used to transition optical fibers between a standard multi-fiber ribbon cable24to a plurality of non-conventional connectors112at the opposite front end60of the cassette body68. If the array102uses a flexible substrate defining a flexible circuit, portions of that substrate supporting the fibers may be physically inserted into the non-conventional connectors112.

It should be noted that the term “non-conventional connector” may refer to a fiber optic connector that is not of a conventional type such as an LC or SC connector and one that has generally not become a recognizable standard footprint for fiber optic connectivity in the industry.

As described and shown in WO 2014/052441, WO 2014/052446, and U.S. Patent Publication No. 2016/0041357, the entire disclosures of which have been incorporated by reference, the non-conventional connectors112that are positioned adjacent the front60of the cassette10may each defines a hub mounted over a ferrule. A split sleeve may also be provided for ferrule alignment between the hub and ferrule of each non-conventional connector112and a ferrule of another mating connector that enters the cassette10from the front60. Each ferrule may be configured to terminate one of the fibers extending out from the insert104. The fiber pigtails extending out from a front end110of the insert104may be individually terminated to the ferrules to be positioned at the front60of the cassette10.

The cassette10may define pockets114at the rear end116of the adapter block62that match the exterior shape of the ferrule hubs (e.g., having square footprints), wherein the pockets114may be configured to fully surround the ferrule hubs. Via the adapter block62, the cassette10is ready to receive fiber optic connections. Mating conventional connectors entering the cassette10from the front60of the cassette10may be connected through fiber optic adapters58that are defined by the adapter block62.

The elimination of conventional mating connectors inside the cassette10may significantly reduce the overall cost by eliminating the skilled labor normally associated with terminating an optical fiber to a connector, including polishing the end face of the fiber and epoxying the fiber into the connector. It further allows the fiber optic interconnect device such as the optical cassette10to be made very thin.

As noted, further details relating to fiber optic cassettes including such non-conventional connectors112are described and illustrated in the above-incorporated WO 2014/052441, WO 2014/052446, and U.S. Patent Publication No. 2016/0041357.

Referring toFIGS. 5-9, for the cassette10shown therein, a signal entry location may be provided by an MPO style adapter90and an MPO style connector92that is within the adapter90at the fixed portion80of the base76of the cassette body68. The ribbon cable24terminated to the MPO connector92carries the fibers that are relayed to the movable portion82of the base76of the cassette body68. From the ribbon cable24, the fibers are transitioned via a fiber optic array102that is supported by a polymeric insert104that is placed within the cassette body68. The pigtails extending forward from the polymeric insert104may be used to form the non-conventional connectors112as noted above. The adapter block62at the front end60of the cassette body68may be configured to mate the non-conventional connectors112positioned at a rear end116of the block62to conventional type connectors (e.g., LC format) coming in from the front60of the cassette10.

Regarding the management of the ribbon cable24within the cassette body68and the two spools96,98, the large spool96is used when the fibers carried by the ribbon cable24are initially terminated within the cassette10, the ribbon cable24extending from the MPO connector92provided within the MPO adapter90at the fixed portion80to the polymeric insert104within the movable portion82.

The small spool98is used if, for any reason, the ribbon cable24has to be re-terminated. When re-terminating a ribbon cable24such as the one used with the cassettes10of the present disclosure, the cable24is cut and the technician can normally lose 20-30 mm of the cable length. The cassette10of the present disclosure is designed such that the small spool98defines a fiber path118that surrounds the spool98that is about 30-40 mm shorter than that defined by the large spool96. Thus, using the small loop or path118, after a re-termination process, ensures that the ribbon cable24will still be able to extend to its fully extended length when the telescopically movable portion82is pulled out. The difference in length between the path118surrounding the large loop96(which is initially used when assembling the cassette10) and the path118surrounding the small loop98is large enough to make up the length that is lost in re-terminating the ribbon cable24. Thus, the cooperation and the positioning of the two spools96,98provides a guide to a technician that may be re-terminating the ribbon cable24. The two spools96,98retain the proper functioning of the cassette10by preventing or limiting any stress that might be put on the fibers of the ribbon cable24via the telescoping movement of the cassette10if such a guide was not used. It should be noted that inFIG. 7, the ribbon cable24is illustrated in an initially terminated configuration where the large spool96is used for managing the cable24. InFIG. 8, the cassette10is shown when a ribbon cable24has been re-terminated, where the cable24is now managed by the small spool98.FIG. 9is a close-up view of a portion of the cassette10ofFIG. 8, wherein the difference between the fiber paths118between the two spools96,98is illustrated schematically.

As shown inFIGS. 5-9, the fixed portion80of the base76defines a notch120for accommodating the spools96,98formed within the movable portion82of the base76. The movable portion82of the base76also defines a notch122for accommodating a portion of the fiber optic adapter90provided on the fixed portion80of the base76. The notches120,122provide a flush fit when the movable and the fixed portions82,80of the base76of the cassette body68are brought together.

Although in the foregoing description, terms such as “top,” “bottom,” “front,” “back,” “right,” “left,” “upper,” and “lower” were used for ease of description and illustration, no restriction is intended by such use of the terms. The telecommunications devices described herein can be used in any orientation, depending upon the desired application.

Having described the preferred aspects and embodiments of the present disclosure, modifications and equivalents of the disclosed concepts may readily occur to one skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.

LIST OF REFERENCE NUMERALS AND CORRESPONDING FEATURES

10—Fiber optic cassette12—Telecommunications chassis14—Telecommunications system16—Rear of chassis18—Front of chassis24—Ribbon cable26—Tray/blade28—Right wall of chassis30—Left wall of chassis32—Mounting flange34—Back wall of chassis36—Backplane38—Connection location/fiber optic adapter40—Cable management structures/cable rings42—Door44—Hinge mechanism46—Slide portion of blade48—Right side of blade50—Left side of blade52—Mounting slot54—Cable management device58—Connection location/fiber optic adapter60—Front end of cassette62—Adapter block64—Notched area66—Rear end of cassette68—Cassette body70—Wider portion of cable manager72—Front end of cable manager74—Thin portion of cable manager76—Base of cassette body78—Cover of cassette body80—Fixed portion of base82—Movable portion of base84—Slide rod86—Stop flange88—Rear end of slide rod90—Fiber optic adapter92—Fiber optic connector94—Opening96—Large spool98—Small spool99—Rear end of movable portion of base100—Interior102—Fiber optic array104—Polymeric insert106—Fiber consolidation point108—Rear end of insert110—Front end of insert112—Non-conventional connector114—Pocket116—Rear end of adapter block118—Fiber path120—Notch122—Notch