Fiber optic management and identification systems and methods

Abstract

The present disclosure relates to a method of preparing a fiber optic circuit, the method comprising coating all of the optical fibers terminated to and extending from a multi- fiber connector with a coating so as to fix the fibers relative to each other to form multiple and separate fiber ribbons, each ribbon including a plurality of coated fibers.

Description

[0001] FIBER OPTIC MANAGEMENT AND IDENTIFICATION SYSTEMS AND METHODS

[0002] Cross-Reference To Related Application

[0003] This application is being filed as a PCT International application and claims the benefit of and priority to U.S. Provisional Application No. 63 / 627,952, filed on February 1, 2024, the disclosure of which is hereby incorporated by reference in its entirety.

[0004] Technical Field

[0005] The present disclosure relates generally to optical fiber management in telecommunications devices. More specifically, the present disclosure relates to optical fibers and methods associated with routing and identification thereof in telecommunications devices.

[0006] Background

[0007] Various devices are used to manage, store, and / or protect optical fibers and optical splices. These devices may include modular cassettes that are removably attached to telecommunications chassis for connectivity. Improvements in fiber layout and marking are needed for optical fiber handling, management, storing, and identification.

[0008] Summary

[0009] An aspect of the present disclosure relates to fiber optic circuits, specifically, preformed optical circuits, wherein the fibers are disposed in a predetermined orientation / layout ready for termination to fiber optic connectors. Such fiber optic circuits may be carried within devices, for example, in the form of fiber optic cassettes.

[0010] Such cassettes may house connectors terminated to the preformed circuit that provide a signal entry location and connectors terminated to an opposite end of the preformed circuit that provide a signal exit location, wherein the fiber optic circuit is positioned within an interior of the cassette for relaying the signal from the entry location to the exit location. The optical circuits of the present disclosure, as well as the equipment the circuits are housed in, can have many forms. A modular cassette is simply one example piece of fiber optic equipment for housing such preformed optical circuits.

[0011] Certain aspects of the present disclosure relate to fiber optic layout and marking solutions for managing and handling of optical fibers, such as in fiber optic equipment, such as modular cassettes.

[0012] In some examples, a flexible foil or substrate may initially be used for manufacturing the preformed fiber optic circuit for fixing the fibers in a given orientation / layout.

[0013] In some cases, the preformed fiber optic circuit can include loose fibers, ribbonized fibers, or fibers supported by a flex foil or substrate, or a combination thereof. In certain examples, the final fiber optic circuit provided within the equipment can include ribbonized and loose fibers, without a flex foil substrate.

[0014] Another aspect of the present disclosure relates to fiber management, layout, and identification in devices where the optical fiber circuit extends from one end to an opposite end of the device. The ends can be connectorized with connectors such as multifiber connectors) (e.g., different types of MPO connectors or MMC16 connectors). The fiber optic circuits within the devices can include loose fibers and ribbonized fibers, or a combination thereof.

[0015] Another aspect of the present disclosure relates to a method of preparing a fiber optic circuit, the method comprising coating all of the optical fibers terminated to and extending from a multi-fiber connector with a coating so as to fix the fibers relative to each other to form multiple and separate fiber ribbons, each ribbon including a plurality of coated fibers.

[0016] According to certain example aspects, each of the separate ribbons includes the same number of optical fibers. According to certain example aspects, the coating for forming the fiber ribbons includes silicone. According to certain example aspects, indicia is provided on the fiber ribbons that are formed by coated fibers, e.g., via laser marking. According to certain example aspects, the provided indicia indicates fiber direction in a given row of fibers in a multi-fiber connector. According to certain example aspects, the provided indicia indicates a given end of the circuit. According to certain example aspects, the provided indicia indicates a designated multi-fiber connector of one of the plurality of multi-fiber connectors. According to certain example aspects, the provided indicia indicates a given row in a multiple-row multifiber connector that is connected to the optical fibers. According to certain example aspects, a portion of the optical fibers positioned after the coated portion in a direction away from the multi-fiber connector are stranded loose fibers. According to certain example aspects, the optical fibers exiting the multi-fiber connector include stranded loose fibers followed by coated fibers forming the multiple ribbons, and followed by stranded loose fibers. According to certain example aspects, at least one layer of flexible foil formed from polyethylene terephthalate (PET) is peeled from the plurality of optical fibers from the fiber optic circuit, wherein the peeled PET flex foil may initially overlap with both the coated fibers forming the multiple ribbons and stranded loose fibers, and wherein the PET flex foil may include indicia marked via laser marking. All of the optical fibers extending from the multi-fiber connector may be coated prior to termination of the optical fibers to the multi-fiber connector or may be coated after termination of the optical fibers to the multi-fiber connector.

[0017] Another aspect of the present disclosure relates to a fiber optic circuit comprising a plurality of optical fibers that connect between a plurality of multi-fiber connectors at one portion of the circuit and a lesser number of multi-fiber connectors at another portion of the circuit, wherein all of the optical fibers terminated to and extending from at least one of the multi-fiber connectors of the circuit are coated with a coating so as to fix the fibers relative to each other to form multiple and separate fiber ribbons, each ribbon including a plurality of coated fibers.

[0018] A further aspect of the present disclosure relates to telecommunications equipment. In certain examples, the telecommunications equipment can include a telecommunications device having at least one multi-fiber connector for supporting signals entering or exiting the telecommunications device, the device comprising a fiber optic circuit comprising a plurality of optical fibers within the device terminated to the at least one multi-fiber connector, wherein all of the optical fibers terminated to and extending from the at least one of the multi-fiber connector are coated with a coating so as to fix the fibers relative to each other to form multiple and separate fiber ribbons, each ribbon including a plurality of coated fibers.

[0019] The various aspects characterized above in this section can be used together or separately in telecommunications arrangements. These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. A variety of additional aspects will be set forth in the description that follows. These aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad concepts upon which the embodiments disclosed herein are based.

[0020] Brief Description of the Drawings

[0021] The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows.

[0022] FIG. 1 is a schematic view showing multiple layers of an example preformed flexible fiber optic circuit that includes a flexible substrate for supporting the fibers in accordance with principles of the present disclosure, wherein at least a portion of the preformed fiber optic circuit includes a plurality of fibers in a predetermined arrangement supported by a layer of flexible polyethylene terephthalate (PET) foil and coated by a silicone coating.

[0023] FIG. 2 illustrates at least a portion of a preformed fiber optic circuit prepared in accordance with the methods of the present disclosure, wherein the portion includes a plurality of fibers in a predetermined arrangement coated by a silicone coating.

[0024] FIG. 3 illustrates at least a portion of the preformed fiber optic circuit prepared in accordance with the methods of the present disclosure, wherein the portion includes uncoated, loose fibers for use in telecommunications equipment.

[0025] FIG. 4 illustrates one example embodiment of a telecommunications device in the form of a conversion module / cassette that utilizes the inventive aspects of the present disclosure.

[0026] FIG. 5 is a side view of a portion of the conversion module of FIG. 4 illustrating the height restrictions imposed by the fiber retaining fingers within the module.

[0027] FIG. 6 is a side view of a portion of the conversion module of FIG. 4 illustrating the height restrictions imposed by the fiber retainers within the module.

[0028] FIG. 7 illustrates a plurality of preformed flexible fiber optic circuits having examples of inventive aspects in accordance with the present disclosure that are designed for termination to multi-fiber connectors within telecommunications devices similar to the module of FIG. 4, one of the fiber optic circuits illustrated schematically as terminated to an example MPO connector.

[0029] FIG. 8 illustrates a plurality of preformed flexible fiber optic circuits having examples of inventive aspects in accordance with the present disclosure that are designed for termination to multi-fiber connectors within telecommunications devices similar to the module of FIG. 4, the fiber optic circuits schematically illustrated with exemplary cut and strip lines and MPO type connectors positioned for 1) initial termination, 2) a first re-work, and 3) a final re-work.

[0030] FIG. 9 illustrates a plurality of preformed flexible fiber optic circuits having examples of inventive aspects in accordance with the present disclosure that are designed for termination to multi-fiber connectors within telecommunications devices similar to the module of FIG. 4, one of the fiber optic circuits illustrated schematically as terminated to an example MPO connector, the fiber optic circuits illustrated with specific indicia designed to show identification of the End A portion of the circuit including the MPO connector numbers and the fiber direction.

[0031] FIG. 10 illustrates a plurality of preformed flexible fiber optic circuits having examples of inventive aspects in accordance with the present disclosure that are designed for termination to multi-fiber connectors within telecommunications devices similar to the module of FIG. 4, one of the fiber optic circuits illustrated schematically as terminated to an example MPO connector, the fiber optic circuits illustrated with specific indicia designed to show identification of the End B portion of the circuit including the multi-fiber connector numbers, the fiber direction, and the designated fiber rows within a given multi-fiber connector.

[0032] FIG. 11 illustrates one example method for visually identifying the separate rows within a given multi-fiber connector such as a 24-fiber MPO connector, wherein a thick arrow may indicate the Row B of a 24-fiber MPO connector (i.e., fibers 13-24) and a standard thickness arrow may be used to indicate either the Row A of a 24-fiber MPO connector (i.e., fibers 1-12) or single-row MPO connector types such as MPO8, MPO 12, or MPO 16 connectors.

[0033] FIG. 11 A illustrates the fiber layout, showing the two rows of twelve fibers, in the ferrule of an example MPO24 connector. FIG. 1 IB illustrates the fiber layout in the ferrule of an example MPO8 connector.

[0034] FIG. 11C illustrates the fiber layout in the ferrule of an example MP012 connector.

[0035] FIG. 1 ID illustrates the fiber layout in the ferrule of an example MP016 connector.

[0036] FIG. 12 illustrates a plurality of fiber optic circuits having examples of inventive aspects in accordance with the present disclosure, the circuits shown with example marking methods, where standard size arrows are used on the End A portion of the circuit for ribbons all being terminated to multi-fiber connectors such as MP08, MP012, or MP016 type connectors.

[0037] FIG. 13 illustrates a plurality of fiber optic circuits having examples of inventive aspects in accordance with the present disclosure, the circuits shown with example marking methods, where the End B portion of the circuits are marked with different thickness arrows used to show the Rows A and Rows B on the different MPO24 type connectors.

[0038] FIG. 14 illustrates another example embodiment of a telecommunications device in the form of a conversion module / cassette similar to the module of FIG. 4 that utilizes the inventive aspects of the present disclosure, the module shown with six multi-fiber connectors at the front for a 2x6 type conversion.

[0039] FIG. 15 illustrates yet another example embodiment of a telecommunications device in the form of a conversion module / cassette similar to the module of FIG. 4 that utilizes the inventive aspects of the present disclosure, the module designed to provide a 3x4 type conversion.

[0040] FIGS. 16-19 illustrate a number of different types of pre-formed fiber optic circuits that can be used in different conversion modules that utilize the inventive aspects of the present disclosure, wherein both the End A and End B sides are illustrated. In FIG. 16, a number of 2x3 conversion type preformed circuits are illustrated (prior to termination). In FIG. 17, a lx2 / 2xl conversion type preformed circuit is illustrated (prior to termination). In FIG. 18, a number of 4x3 conversion type preformed circuits are illustrated (prior to termination). And, in FIG. 19, a 1x3 conversion type preformed circuit is illustrated (prior to termination). FIG. 16A illustrates a close-up view of the End A side of one of the 2x3 conversion type preformed circuits of FIG. 16.

[0041] FIG. 20 illustrates a number of alternative examples of markings or indicia that can be utilized in preformed circuits in accordance with the inventive aspects of the present disclosure.

[0042] Detailed Description

[0043] The present disclosure is directed generally to pre-formed fiber optic circuits (e.g., initially via flexible foil elements). In certain examples, the aspects of the present disclosure can be configured for use within telecommunications equipment such as modular cassettes that are removably mounted to telecommunications chassis. The inventive aspects can be utilized in other types of telecommunications devices.

[0044] Referring now to FIG. 1, one example of a preformed fiber optic circuit according the present disclosure is schematically illustrated. In the illustrated example, the preformed fiber optic circuit discussed herein can include one or more (typically, multiple) optical fibers attached to and supported by a flexible planar substrate, such as a Mylar™ or other flexible polymer substrate. Although specific examples herein depict and describe planar substrates, it should be appreciated that other substrate configurations, e.g., in which a substrate fixes optical fibers in and / or across multiple planes are also contemplated. In certain examples, as will be discussed below, the optical fibers extend past ends of the flexible film elements 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.

[0045] The flexible film elements can be used to construct preformed fiber optic circuits, as noted above. Examples of such fiber optic circuits are disclosed in PCT International Publication No. W02019 / 070682A2, the disclosure of which is incorporated herein by reference in its entirety.

[0046] Still referring to FIG. 1 , a schematic view showing the multiple layers of the example preformed flexible fiber circuit 10 in accordance with principles of the present disclosure is illustrated. The fiber circuit 10 can include an example film element 12 and one or more optical fibers 14 supported by the film element 12. The film element 12 can include a composite structure that may include at least three layers of which one layer is a flexible planar substrate 16 (e.g., a flexible foil element in the form of a polyethylene terephthalate (PET) foil), a silicone coating layer 18, and an adhesive layer 20 for bonding the optical fibers 14. The flexible planar substrate 16 may also have a siliconized side 19 to facilitate release during construction opposite the adhesive side 20.

[0047] Example adhesives include epoxy, light curable adhesive (e.g., ultraviolet light curable adhesive), thermo-form adhesive, thermo-set adhesive, index-matching adhesive or other adhesives. In certain examples, the adhesive layer 20 can be deposited on top of the flexible planar substrate 16.

[0048] As noted above, in certain examples, the flexible planar substrate 16 may be formed from polyethylene terephthalate (PET). However, it would be understood that PET is simply one non-limiting example polymer that may be used to form the flexible planar substrate 16 of the present disclosure, and other polymers having similar characteristics can be used in accordance with the principles of the present disclosure, such as Mylar™.

[0049] The adhesive layer 20 on the flexible planar substrate 16 may be adapted to support the optical fibers 14. That is, one or more optical fibers 14 can be routed on the flexible planar substrate 16, typically with a needle extending from a robotic arm, and then secured to the flexible planar substrate 16 with the adhesive layer 20, which is allowed to set or cure.

[0050] As noted above, in certain examples, an additional optional layer of material or coating 18 can be applied on top of the optical fibers 14 and the adhesive layer 20 to affix the optical fibers 14. Any suitable material can be used for this purpose. In one non-limiting example, an elastomer such a silicone coating can be applied on top of the optical fibers 14 and the adhesive layer 20. The silicone coating layer 18 may be used to supplement the adhesive layer 20 to fix the optical fibers 14 onto the flexible planar substrate 16 and to cover the adhesive layer 20 to limit tackiness.

[0051] The film element 12 described above is one example of a composite flex foil based preformed fiber optic circuit that can be used to initially construct the telecommunications equipment in accordance certain aspects of the present disclosure, as will be discussed in further detail below.

[0052] A preformed fiber optic circuit 10 such as that shown in FIG. 1 utilizing a flexible substrate 16 provides a number of advantages. For example, the assembly of the fiber optic circuit 10 allows a designer or technician to fix the optical fibers 14 in a predictable and automated manner such that a desired orientation or layout of the optical fibers 14 can be achieved. The film elements 12 are preferably constructed with a foil 16 that is adapted to fix the optical fibers 14 that follows fiber bend radius limits and requirements. Preferably, the composite film elements 12 do not break or kink to ensure the safety and protection of the optical fibers 14 during manufacturing of the circuit or later handling. In certain examples, the film elements 12 may be bendable in such a way that the optical fiber bend radius requirements are respected and satisfied.

[0053] In certain other examples, the film elements 12 may have a flexibility that allows the film elements to flex along a bend smaller than a minimum bend radius of the optical fiber or fibers if desired.

[0054] As noted above, in certain configurations, portions of the preformed fiber optic circuits 10 described herein can include loose fibers 14 or single stranded fibers 14 that are not coated (FIG. 3). In other areas of the pre-formed fiber optic circuits of the present disclosure, the circuit 10 can include ribbonized fibers (FIG. 2). The ribbonized fibers can be coated fibers 14 that are coated by, for example, a silicone layer 18 as noted above. Example methods of preparation of the various areas of the preformed fiber optic circuit of the present disclosure are discussed in PCT Publication No. W02019 / 070682A2, the disclosure of which has been incorporated herein by reference in its entirety.

[0055] Referring now specifically to FIG. 2, illustrated is a portion of the pre-formed fiber optic circuit 10 that is referred to as the ribbon portion 22. The ribbon portion 22 includes the silicone coated fibers 14 with the adhesive layer 20. The silicone coating 18 may interact with the adhesive layer 20, and the combination may result in a ribbonized layer 22. As shown, the ribbon portion 22 does not include the PET foil layer 16, discussed above for the preformed circuit of FIG.1. The PET foil layer 16 may be removed by peeling, leaving the ribbon portion 22 with the silicone coated fibers 14.

[0056] And, referring now specifically to FIG. 3, a stranded fiber portion 14 of the preformed optical circuit 10 is illustrated. As shown in FIG. 3, a silicone coating 18 is not applied to the fibers 14 and the fibers 14 are individually stranded, with the ability to separate, flex, and be individually routed within a piece of telecommunications equipment. Such stranded fibers 14 may be factory-coated with a silicone coating 18 to form a ribbon 22 as discussed above, or may be coated after termination in certain instances.

[0057] Referring now to FIGS. 4-20, the present disclosure is directed generally to methods utilizing the fiber optic circuits 10 described above, specifically, the preformed optical circuits 10, wherein the fibers 14 are disposed in a predetermined orientation / layout ready for termination to fiber optic connectors. Such fiber optic circuits 10 may be utilized within devices, for example, in the form of fiber optic cassettes that include connectors for providing a signal entry location and connectors that provide a signal exit location, wherein portions of such fiber optic circuits 10 are positioned thereinbetween for relaying the signal from the entry location to the exit location.

[0058] As noted above, the use of preformed circuits 10 (that include an initially provided flex foil 16) in accordance with the present disclosure can provide a number of advantages. For example, the use of a preformed circuit 10 allows a designer or technician to fix the fibers 14 in a given orientation, wherein the circuit layouts may be produced in a predictable and automated manner. Manual handling and positioning of the fibers 14 within a piece of equipment may be reduced and eliminated through the use of preformed optical circuits 10. Complexity of the circuits 10 can be increased due to the pre-fixed positioning of the fibers 14. Termination of the fibers 14 may be facilitated. Methods of the present disclosure that are used to pre-fix the fibers 14 allow the designers to optimize fiber bend radius limits and requirements in configuring the equipment in which they are used, thus, achieving reduced dimensions for the equipment. The bend radius of the fibers 14 can thus be controlled to a minimum diameter.

[0059] Still referring to FIGS. 4-20, aspects of the present disclosure are directed to the use of at least portions of such preformed optical circuits 10 in fiber optic devices so as to facilitate routing and identification of the fibers 14 in telecommunications devices.

[0060] It should be noted that the optical circuits 10 of the present disclosure, as well as the equipment the circuits 10 are housed in, can have many forms. A modular cassette 100 is simply one example piece of fiber optic equipment for housing such preformed optical circuits 10 and will be used to describe inventive aspects of the present disclosure. An example of a fiber optic cassette 100 that can utilize aspects of the preformed fiber optic circuits 10 of the present disclosure is shown in FIG. 4.

[0061] The fiber optic device 100 illustrated in FIG. 4 may be referred to as conversion module or cassette that is designed to house a multi-fiber connector to multi-fiber connector optical circuit 10 therewithin. It should be noted that many of the illustrated and discussed examples of multi-fiber connectors herein are MPO type connectors, and the inventive aspects will be discussed with respect to MPO type connectors for demonstrative purposes. However, the inventive aspects herein should not be limited to the specific types of connectors shown or discussed. Multi-fiber connectors can include different types of MPO connectors, MMC16 connectors, and other types).

[0062] The fiber optic circuit 10 of the conversion module of FIG. 4 is configured such that the optical fibers 14 therein include a first plurality that connect between a plurality of the multi-fiber connectors 102 at one portion of the cassette 100 and a lesser number of multi-fiber connectors 102 at another portion of the cassette 100, and a second plurality of fibers 14 that only connect to at least one of the multi-fiber connectors 102 at the one portion and are dark fibers, wherein the multi-fiber connectors 102 provided at the one portion of the cassette 100 do not use all of the fiber signal paths for transmitting signals and include some dark fibers, and the lesser number of the multifiber connectors 102 provided at the another portion of the cassette 100 use all of the fiber signal paths for transmitting signals.

[0063] In such a cassette 100, as illustrated in FIG. 4, the fiber optic circuit 10 provided therein may be a passive circuit such that uninterrupted fiber pathways are established between the multi-fiber connectors 102 at the one portion of the cassette 100 and the lesser number of multi-fiber connectors 102 at the another portion of the cassette 100 for all of the first plurality of optical fibers 14 without any power or wavelength splitting or switching for the fiber signal paths, and wherein the first and second plurality of optical fibers 14 connected to the at least one of the multi-fiber connectors 102 at the one portion of the cassette 100 may be provided in a common pattern of signal-transmitting fibers, dark fibers, and signal-transmitting fibers.

[0064] In the cassette 100 shown in FIG. 4, in the depicted example, twelve-fiber MPO connectors 102 may be used (including a single row or multiple rows of twelve fibers (for example, two to six rows)). In an example such as the depicted cassette 100, as noted above, not all fibers 14 may be signal / light carrying. These fibers may be dark or unused “dummy” fibers but still form part of the optical circuit 10. Such a construction enables ease of assembly by connecting all twelve (or multiples of twelve) fibers 14 at the same time. If the unused fibers were not present, there is a chance the multi-fiber ferrules of the MPO connectors 102 could become damaged during polishing if open bores were present through the ferrules.

[0065] Still referring to FIG. 4, the cassette 100 includes a body 104 defining a front 106, a rear 108, and an interior 110. The body 104 may include a cover (removed for illustrating the internal features of the cassette 100) that defines the top of the cassette 100, a bottom 112, and sides 114.

[0066] In general, cassette 100 includes the top and bottom which are generally parallel to each other and define the major surfaces of cassette body 104. Sides 114, front 106, and rear 108 generally define the minor sides of cassette body 104. The cassette 100 can be oriented in any position, so that the top and bottom surfaces can be reversed, or positioned vertically, or at some other orientation.

[0067] The cassette 100 of FIG. 4 can be sealed or can be openable, so as to allow repair or re-work. The fiber optic circuit 10 may allow the entire fiber bundle, including the MPO connectors 102 therein to be able to be removed for cleaning or replacement.

[0068] Still referring to FIG. 4, certain aspects of a piece of telecommunications equipment such as the fiber optic cassette 100 shown in FIG. 4 may necessitate fiber management solutions having inventive aspects within the present disclosure.

[0069] For example, as shown for the embodiment of the cassette 100 in FIG. 4, the cassette 100 may include cable management features such as fiber retaining fingers 116 that are provided adjacent the front 106 and the back 108 of the cassette 100. Such fiber retaining fingers 116 may impose height restrictions. According to one embodiment, each fiber retaining finger 116 (as shown in FIG. 5) may impose a height restriction of about 3mm. Regarding similar aspects, the cassette 100 may also feature fiber retainers 118 provided toward the center of the cassette body 104 for also managing and retaining fiber loops, as illustrated. Such fiber retainers 118 may also impose height restrictions. In the given example, as shown in FIG. 6, a height restriction of about 2.65mm is imposed by each fiber retainer 118.

[0070] It should be noted that a twelve-fiber ribbon 22 extending from an example MPO connector 102 may define a height (or, stated in a different way, a width) of about 3mm. A typical sixteen-fiber ribbon 22 may define a height (or, stated in a different way, a width) of about 4mm. Thus, if such ribbons 22 are needed to be routed within a given cassette 100, the height restrictions imposed by features such as the fiber retaining fingers 116 and the fiber retainers 118 may present issues. When a ribbonized group of fibers 14 are twisted such that the fibers 14 are laying in a vertical orientation within the cassette 100 during looping of fibers, even a twelve-fiber ribbon 22 may not fit within one of the shown fiber retainers 118 without risk of damage to the fibers 14. The height restrictions may also be a concern when ribbons 22 have to be routed within the cassette 100 such that ribbons 22 cross over each other at certain areas within the cassette 100. Assembly and manufacture of such cassettes 100 may become difficult, and the constraints within the cassettes 100 may lead to unwanted micro and macro bends of the fibers 14.

[0071] According to one example inventive aspect, one solution to the height restriction noted above is to split a given twelve-fiber ribbon 22 coming out of an example MPO connector 102 into two ribbons 22. According to one example, the two ribbons 22 can be equal size (width / height) ribbons 22. For example, a twelve-fiber ribbon 22 coming out of an MPO connector 102 can be split into two six-fiber ribbons 22, each having a width of 1.5mm. Similarly, as an example, a sixteen-fiber ribbon 22 may be split into two equal width eight-fiber ribbons 22, each defining a width of 2mm. When the fiber groups are provided in the form of multiple ribbons 22, the ribbons 22 can also nest on top of each other when laying under the cable management structures within a given cassette 100, facilitating management and limiting potential damage to the fibers 14.

[0072] Now referring to FIG. 7, when forming such a circuit 10, a group of fibers 14 that is coming into the cassette 100 from one side of an example MPO connector 102 may be provided in the form of loose stranded fibers 14 when initially exiting the MPO connector 102. According to the principles of the present disclosure, a silicone coating 18 may be applied after a given length of the stranded fibers 14 such that two separated ribbons 22 are formed. The provision of loose fibers 14 coming out of the example MPO connector 102 may facilitate with sharp bends that occur right away when fibers 14 are coming out of the MPO connector 102 as illustrated in the cassette 100 of FIG. 4. The ribbonizing of the fibers 14 after a specified length and providing multiple ribbons 22 helps with cable management within the cassettes 100 while providing other advantages such as labeling as will be discussed below.

[0073] As shown in FIG. 7, the fiber bundles that are coated with silicone 18 to form fiber ribbons 22 provide the advantage of marking for identification of the connector numbers, the fiber direction, and the end orientation for polarity. It should be noted that the fibers 14 leading further right after the coated section 22 (as seen in FIG. 7) can remain loose fibers 14 that are routed within the cassette 100 until those fiber bundles reach the “End B” side of a circuit 10. The loose stranded fibers 14 help with the sharper bends that might occur within the devices such as the cassettes 100.

[0074] Keeping fibers in a ribbon 22 with silicone coating 18 facilitates with marking purposes, as shown in FIG. 7. Ribbonizing the fibers 14 allows laser marking on the ribbons 22.

[0075] An example of a preformed fiber optic circuit 10 that utilizes some of the inventive aspects is shown in FIG. 8. As shown, the preformed circuit 10 might be provided with a PET foil based substrate 16 (as shown in FIG. 1) at the left side of the circuit 10. The PET foil 16 allows “MID” marking 39 before termination. As also shown, the fibers 14 extending from the PET foil 16 are coated with silicone 18 to form a ribbon 22. As shown, the ribbon 22 can be laser marked with an initial cut line 24 and also an initial strip line 26 for termination purposes. Such a circuit 10 is schematically shown in FIG. 7 after having been terminated to an example MPO connector 102. After termination, as discussed before, the fibers 14 extending from the right side of the MPO connector 102 are provided as loose fibers 14 for allow sharper bends, and further down, the fibers 14 are coated with silicone 18 to form the multiple ribbons 22. As noted previously, the coating 18 on the ribbons 22 allow laser marking for identification purposes.

[0076] Still referring to FIG. 8, a final strip line 28 may also be laser marked on the coated portion 22. The final strip line 28 shows the point where a group of fibers 14 can be stripped if a re-work or re-termination is required for a damaged ribbon 22 on a given multi-fiber connector 102.

[0077] It should be noted that the depicted example illustrates two cut and strip lines for re-work purposes. It will be understood that in other embodiments, a higher number of cut and strip lines (e.g., four lines) for providing more re-work options can be marked. As also shown in FIG. 8, in the preformed circuit 10, PET foil portions 16 (as illustrated in FIG. 1) may be provided at the right side of the circuit 10 to keep fibers 14 organized before termination. Such PET layers 16 may be peeled off and discarded after termination, leaving just the silicone coated ribbons 22 that lead into the cassettes 100. Provision of such PET foils 16 at the right side of the circuit 10 may help with both the transition of the fibers 14 from loose fibers 14 to coated ribbonized fibers 22 and from the transition of the ribbonized fibers 22 to loose fibers 14, as the fibers 14 continue further right. When peeling the PET foils 16 after termination, it might be preferable to peel them from left to right (from the coated side 22 toward the uncoated side 14) to minimize risk to the individual stranded fibers 14, while keeping left side ribbonized. The PET foil 16 at the right side may be provided as a large substrate with a number of kiss-cuts or perforation lines 30 for separating the substrate 16 into smaller PET foils. As such, after termination to each of the MPO connectors 102, these PET foils 16 can be removed separately.

[0078] As discussed previously, the ribbonized portions 22 of the circuit 10 provide the advantage of laser marking for fiber identification and layout for the technicians.

[0079] The laser marking may be provided in a number of different ways to show fiber orientation and connector identification. In the example shown in FIG. 8, as illustrated, a marking of letter “A” indicates the “End A” of the circuit 10. Arrows 32 are laser marked, as shown, to indicate the direction of “Fiber #1” in a given row of fibers within an example MPO connector 102. And, the number of arrows 32 laser marked can indicate the number of the MPO connectors 102 to which the ribbons 22 are to be terminated. It should be noted that additional identification may be provided by the provision of laser-marked large solid lines 34, that define the arrows 32.

[0080] As shown in the circuit 10 in FIG. 9, for example, the lengths of the large solid lines 34 may provide additional identification of the MPO connector number in addition to the number of arrows 32. All of the “End A” side of the circuit 10 may be indicated by the large solid lines 34.

[0081] As shown in FIG. 10 and as will be discussed in further detail, the “End B” side of the circuit 10 may be the inverse of the marking on the “End A” side, where solid arrows 36 instead of solid lines 34 are marked for indicating both the number of the MPO connectors 102 and the direction of “Fiber #1 in a given row of fibers 14 at the “End B” side. As noted above, the PET foil 16 provided on the left side of the preformed circuit 10 can be used to mark information on the circuit such as the “MID” number 39, which can be helpful with inventory purposes.

[0082] Now referring back to FIG. 7, as noted above, one of the preformed circuits 10 is shown schematically with an example MPO connector 102 terminated, showing the position of the MPO connector 102 on the circuit 10.

[0083] FIG. 8 illustrates the positions of example MPO connectors 102 for an initial termination, where an initial strip is used, and for re-works. As shown, a MPO connector 102 may be positioned anywhere in the re-work zone. A position of an MPO connector 102 in a final re-work zone is also shown in FIG. 8 schematically. As noted above, in other embodiments, a higher number of cut and strip lines for allowing more re-works can be provided.

[0084] Still referring to FIG. 8, when labeling the “End A” side of the circuit 10, as noted above, a laser mark 38 with the letter “A” may be provided initially before termination in the preformed circuit 10. However, once the fibers 14 are terminated to the MPO connectors 102, the connector bodies (specifically the outer housings) may cover up the letter “A” laser mark 38. Thus, after termination, the solid fines 34 marked “around” the arrows 32 indicate that this given side is “End A”. And, as also noted above, as illustrated in FIG. 10, the “End B” side may be provided with the inverse marking, where solid arrows 36 indicate the “End B” side, after an initial letter “B” laser mark 28 becomes covered up after termination.

[0085] As noted above, the multi-fiber connector numbers can be indicated by the number of arrows 32 / 36. However, now referring to FIG. 11, for types of MPO connectors 102 that are twenty-four-fiber MPO connectors 102 with two rows of twelve fibers 14, the thickness of the arrows can be changed for visually identifying the separate rows within a given twenty-four-fiber MPO connector.

[0086] For example, as shown in FIG. 11, a thick arrow 40 may be used to always indicate the Row B of a twenty-four-fiber MPO connector 102 (i.e., fibers 13-24). And, a standard thickness arrow 32 / 36 may be used to indicate either single row MPO connector types such as MPO8, MPO 12, or MPO 16 connectors 102 or may be used to indicate Row A of a twenty-four-fiber MPO connector (i.e., fibers 1-12).

[0087] FIG. 11 A illustrates the fiber layout, showing the two rows of twelve fibers 14, in the ferrule of an example MPO24 connector 102. FIG. 1 IB illustrates the fiber layout in the ferrule of an example MPO8 connector 102.

[0088] FIG. 11C illustrates the fiber layout in the ferrule of an example MPO 12 connector 102.

[0089] FIG. 1 ID illustrates the fiber layout in the ferrule of an example MPO16 connector 102.

[0090] FIG. 12 illustrates an example marking, where standard size arrows 32 are used on the “End A” for ribbons all being terminated to non MPO24 types.

[0091] FIG. 13 illustrates the “End B” side where different thickness arrows 36 / 40 may be used to show the Rows A and Rows B on the different MPO numbers.

[0092] Referring to FIG. 13, as illustrated, a single thick arrow 40 is used for Row B of an MPO24 connector 102 that is connector #1. A single standard arrow 36 is used for Row A of an MPO24 connector 102 that is connector #1. Moving further down, two thick arrows 40 are used for Row B of an MPO24 connector 102 that is connector #2. Two standard arrows 36 are used for Row A of an MPO24 connector 102 that is connector #2. Three thick arrows 40 are used for Row B of an MPO24 connector 102 that is connector #3. And, three standard arrows 36 are used for Row A of an MPO24 connector 102 that is connector #3.

[0093] As noted previously, the ribbon-splitting and marking concepts discussed above can be used on a number of telecommunications devices that might utilize multi-fiber connectors 102. The shown cassettes 100 are simply one example equipment where these concepts can be utilized and can be advantageous. Other densities can be utilized. FIG. 14 illustrates an example of a cassette 200 that has six MPO type connectors 102 at the front for a 2x6 conversion. FIG. 15 illustrates an example of a cassette 300 that provides a 3x4 conversion.

[0094] FIGS. 16-19 also illustrate a number of different types of pre-formed fiber optic circuits 10 that can be used in different conversion modules / cassettes that utilize the aspects of the present disclosure. Both the End A and End B sides are illustrated in the examples of FIGS. 16-19. In FIG. 16, specifically, a number of 2x3 conversion preforms 10 are illustrated (prior to termination). In FIG. 17, specifically, a lx2 / 2xl conversion preform 10 is illustrated (prior to termination). In FIG. 18, specifically, a number of 4x3 conversion preforms 10 are illustrated (prior to termination). And, in FIG. 19, specifically, a 1x3 conversion preform 10 is illustrated (prior to termination). As shown, the PET foils 16 at the left side of the preform 10 may be marked with the “MID” numbers 39 for identifying the different circuits and methodology for inventory purposes.

[0095] It should also be noted that the PET foils 16 at each end (right and left) of the preformed circuits 10 that are provided prior to termination can be advantageously used for other inventive purposes. For example, the ultimate ends 42 of the ribbons 22 may be fixed with the PET foils 16 such that they are provided in a staggered arrangement, as shown in a close-up view in FIG. 16A. Each of the fibers 14 are laid on the PET foil 16 to alternate between a long and a short tail as the fibers 14 extend along the row. The staggering of the fiber tails or ends 42 visually indicates to a technician that the fibers 14 are laid in the proper orientation and provides a secondary check as to the layout of the fibers 14 during the initial manufacture process. If the endpoints 42 are staggered properly, (long, short, long...), the technician will be able to visually confirm that the fibers 14 have been laid on the PET foil 16 properly, ready for termination.

[0096] Such PET foils 16 may also be advantageous to fix “dummy” or dark fibers 14 that might be used in such conversion circuits 10. The PET foils 16 might provide a rigid platform to fix the dummy fibers 14 in the correct spacing.

[0097] Also, as noted above, even though certain example markings or indicia have been described above indicating the number of the correct multi-fiber connectors 102, the correct End A or B of the circuit 10, and the correct direction of the fibers 14, the examples discussed herein are not meant to be limiting and that other types of markings or indicia can be used according to the inventive concepts disclosed herein, especially with respect to laser marking of the coated portions 22 of the circuits 10, while splitting the coated portions 22 into multiple ribbons 22 for facilitating cable management. The direction of the arrows 32 / 36 / 40, the thickness of the arrows 32 / 36 / 40, the coloring of the coated fibers 14 and arrows 32 / 36 / 40, the length of the colored portions, the letter markings 38 are all examples of marking or indicia that can be used to practice the inventive aspects of the present disclosure.

[0098] FIG. 20 illustrates a number of other different examples of markings or indicia 50 that can be utilized in accordance with the inventive aspects of the present disclosure. As shown in a few of the examples, “numbers” 52 may be laser marked. In other examples, “triangles” 54 (smaller and larger for different rows) that point in a certain direction for polarity may be used. In such examples, the number of the triangles 54 may be used to indicate the multi-fiber connector numbers. It should be noted that in certain examples, fiber ribbons 22 that are coated with silicone 18 may be marked. In other examples, the markings 50 may be provided on PET foils 16 that are additionally provided to support the ribbonized fibers 22 prior to termination. Such PET foils 16 may be peeled and discarded after termination as mentioned above.

[0099] The circuits 10 shown in FIG. 20 also illustrate the aspect that there might be more than two split ribbons 22. For example, a bundle of fibers 14 may be split into three coated ribbons 22 for larger capacity multi-fiber connectors 102.

[0100] Although loose stranded fibers 14 are advantageous for cable management and layout within devices such as cassettes 102, the inventive aspects of the present disclosure provide a solution that combines the concept of loose fibers 14 with split ribbonized fibers 22 for facilitating management as well as providing a platform for fiber marking and identification for re-work purposes after termination.

[0101] It should also be noted that in certain re-work applications, the initially coated sections of the ribbons 22 that have been coated with silicone 18 might have to be manually “extended” or re-coated by using coating such as adhesives such that those sections can be re-terminated to multi fiber connectors 102. For example, during rework, if the coated section 22 has to be cut and stripped, leaving only stranded fibers 14, these stranded fibers 14 might need to be re-coated manually for re-termination to limit damage to the fibers 14 during termination.

[0102] To summarize certain aspects, the new inventive aspects of the disclosure can be incorporated into various fiber optic devices. In a conversion circuit 10, each end may include coated regions 22 with a section of uncoated fibers 14 between them. The uncoated section of fiber 14 may assist with sharp bending as fibers exit an example MPO connector 102 into a cassette / module 100. To reduce the height / width of the coated fibers inside a module 102, a single row of uncoated fibers 14 may be divided into two rows prior to factory silicone coating (two equal-width or height ribbons 22 rather than one full-width or height ribbon 22). This solution might reduce congestion inside a module 100 and limit damage to fibers 14. Certain markings or indicia such as arrow markings may be used to identify the MPO connector numbers. In the case of larger capacity multi-fiber connectors 102 such as MPO24 connectors 102, a standard width may be used for Row A arrows 32 / 36 (fibers 1-12), and Row B arrows 40 (fibers 13-24) may be thicker. To assist with Ends A and B identification following connectorization, the internal geometry of End B arrows 36 / 40 may be filled with laser markings and End A arrows 32 may be created by laser marking the area outside the arrow geometry, providing an inverse of the End B side. In such an example, the internal geometry of End A arrows 32 would be the same color as the fiber 14. From the forgoing detailed description, it will be evident that modifications and variations can be made without departing from the spirit and scope of the disclosure.

Claims

What is claimed is:

1. A method of preparing a fiber optic circuit, the method comprising: coating all optical fibers terminated to and extending from a multi-fiber connector with a coating so as to fix the fibers relative to each other to form multiple and separate fiber ribbons, each ribbon including a plurality of coated fibers.

2. A method according to claim 1, wherein each of the separate fiber ribbons includes the same number of optical fibers.

3. A method according to claim 1, wherein the coating for forming the fiber ribbons includes silicone.

4. A method according to claim 1 , further comprising providing indicia on the fiber ribbons that are formed by coated fibers.

5. A method according to claim 4, further comprising providing the indicia via laser marking the coated fibers.

6. A method according to claim 4, wherein the provided indicia indicates fiber positioning such as the position of fiber #1 in a given row of fibers in a multi-fiber connector.

7. A method according to claim 4, wherein the fiber optic circuit has two ends, each end terminated with a multi-fiber connector, wherein the provided indicia indicates a given end of the circuit.

8. A method according to claim 4, wherein the fiber optic circuit includes a plurality of multi-fiber connectors terminated to optical fibers at one end of the circuit, wherein the provided indicia indicates a designated multi-fiber connector of one of the plurality of multi-fiber connectors.

9. A method according to claim 4, wherein the provided indicia indicates a given row in a multiple row multi-fiber connector that is connected to the optical fibers.

10. A method according to claim 1 , wherein a portion of the optical fibers positioned after the coated portion in a direction away from the multi-fiber connector are stranded loose fibers.

11. A method according to claim 1 , wherein the optical fibers exiting the multi-fiber connector include stranded loose fibers followed by coated fibers forming the multiple ribbons, and followed by stranded loose fibers.

12. A method according to claim 1 , further comprising peeling at least one layer of flexible foil formed from polyethylene terephthalate (PET) from the plurality of optical fibers from the fiber optic circuit.

13. A method according to claim 12, wherein the peeled PET flexible foil initially overlaps with both the coated fibers forming the multiple ribbons and stranded loose fibers.

14. A method according to claim 12, wherein the PET flexible foil includes indicia marked via laser marking.

15. A method according to claim 1, further comprising coating all of the optical fibers extending from the multi-fiber connector prior to termination of the optical fibers to the multi-fiber connector.

16. A method according to claim 1, further comprising coating all of the optical fibers extending from the multi-fiber connector after termination of the optical fibers to the multi-fiber connector.

17. A fiber optic circuit comprising: a plurality of optical fibers that connect between a plurality of multifiber connectors at one portion of the circuit and a lesser number of multi-fiberconnectors at another portion of the circuit, wherein all of the optical fibers terminated to and extending from at least one of the multi-fiber connectors of the circuit are coated with a coating so as to fix the optical fibers relative to each other to form multiple and separate fiber ribbons, each ribbon including a plurality of coated fibers.

18. A fiber optic circuit according to claim 17, wherein each of the separate ribbons includes the same number of optical fibers.

19. A fiber optic circuit according to claim 17, further comprising indicia on the fiber ribbons that are formed by coated fibers.

20. A fiber optic circuit according to claim 19, wherein the indicia is provided via laser marking the coated fibers.

21. A fiber optic circuit according to claim 19, wherein the provided indicia indicates fiber positioning such as the position of fiber #1 in a given row of fibers in a multi-fiber connector.

22. A fiber optic circuit according to claim 19, wherein the provided indicia indicates a given end of the circuit.

23. A fiber optic circuit according to claim 19, wherein the provided indicia indicates a designated multi-fiber connector for the portion of the circuit that has a plurality of multi-fiber connectors.

24. A fiber optic circuit according to claim 19, wherein the provided indicia indicates a given row in a multiple-row multi-fiber connector that is connected to the optical fibers.

25. A fiber optic circuit according to claim 17, wherein a portion of the optical fibers positioned after the coated portion in a direction away from a multi-fiber connector are stranded loose fibers.

26. A fiber optic circuit according to claim 17, wherein the optical fibers exiting the at least one multi-fiber connector include stranded loose fibers followed by coated fibers forming the multiple ribbons, and followed by stranded loose fibers.

27. A fiber optic circuit according to claim 17, further comprising at least one layer of flexible foil formed from polyethylene terephthalate (PET) supporting the coated fibers.

28. A fiber optic circuit according to claim 27, wherein the PET flexible foil overlaps with both the coated fibers forming the multiple ribbons and stranded loose fibers.

29. A fiber optic circuit according to claim 27, wherein the PET flexible foil includes indicia marked via laser marking.

30. A telecommunications device having at least one multi-fiber connector for supporting signals entering or exiting the telecommunications device, the device comprising: a fiber optic circuit comprising a plurality of optical fibers within the device terminated to the at least one multi-fiber connector, wherein all of the optical fibers terminated to and extending from the at least one of the multifiber connector are coated with a coating so as to fix the fibers relative to each other to form multiple and separate fiber ribbons, each ribbon including a plurality of coated fibers.

31. A telecommunications device according to claim 30, wherein the device includes a multi-fiber connector at each end of the circuit.

32. A telecommunications device according to claim 30, wherein the device includes a plurality of multi-fiber connectors at each end of the circuit, all of the optical fibers of the circuit being terminated to multi-fiber connectors.

33. A telecommunications device according to claim 30, wherein the device is a conversion module such that the plurality of optical fibers within the device connect between a plurality of the multi-fiber connectors at one portion of the module and a lesser number of multi-fiber connectors at another portion of the module.

34. A telecommunications device according to claim 31 , wherein some of the optical fibers that extend between the plurality of the multi-fiber connectors at one portion of the module and the lesser number of multi-fiber connectors at the another portion of the module are dark fibers that do not carry an active signal.

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