Prefabricated optical fiber ribbon cable for connectorizing with a terminal connector and methods of connectorizing and fabricating the same

• US 6,442,318 B1
• Filed: 11/22/2000
• Issued: 08/27/2002
• Est. Priority Date: 11/23/1999
• Status: Active Grant

• Current Assignee: Schott Fiber Optics, Inc. (Carl-Zeiss-Stiftung)
• Original Assignee: Schott Fiber Optics, Inc. (Carl-Zeiss-Stiftung)
• Inventors: Goldman, Paul D.
• Primary Examiner(s): Sircus, Brian
• Assistant Examiner(s): Le, Thanh-Tam
• Application Number:
  US09/718,434
• Time in Patent Office: 643 Days
• Field of Search: 385/59, 385/114, 385/115, 385/116
• US Class Current: 385/114
• CPC Class Codes: G02B 6/06 the relative position of the fibres being the same at both ends, e.g. for transporting images
• CPC Class Codes: G02B 6/3833 Details of mounting fibres in ferrules; Assembly methods; Manufacture
• CPC Class Codes: G02B 6/3834 Means for centering or aligning the light guide within the ferrule
• CPC Class Codes: G02B 6/3861 Adhesive bonding adhesives in general C09J
• CPC Class Codes: G02B 6/3878 comprising a plurality of ferrules, branching and break-out means
• CPC Class Codes: G02B 6/3885 Multicore or multichannel optical connectors, i.e. one single ferrule containing more than one fibre, e.g. ribbon type optical ribbon cable G02B6/4403, G02B6/448
• CPC Class Codes: G02B 6/448 Ribbon cables

Abstract

An optical fiber ribbon cable includes at least two optical fibers with their centers maintained in spaced relationship by at least one spacer fiber in abutting relationship with and between the optical fibers. The optical fibers and the at least one spacer fiber are maintain together and protected by an encapsulation layer. The optical fibers are made from a material that is relatively insoluble in at least one solution in which the encapsulation layer and the spacer fibers are relatively soluble. The optical fiber cable is connectorized to a multifiber terminal connector by dissolving the encapsulation layer and the spacer fibers along a some length of the ribbon cable, inserting the remaining optical fiber segments into corresponding fiber-receiving channels within the terminal connector and securing the fiber segments within the fiber-receiving channels.

Claims

1. An elongated optical fiber cable for connectorization to a multifiber terminal connector having a plurality of laterally spaced fiber-receiving channels, the optical fiber cable comprising:

at least two elongated optical fibers comprising a first optical fiber and a second optical fiber, each optical fiber having first and second ends, a fiber center, a fiber width and a fiber height and being fabricated from a first material;

at least one connectorization region including at least one spacer fiber fabricated from a third material and having a length, a spacer center, a width and a height, the at least one spacer fiber being abuttingly positioned between the first and second optical fibers to maintain the fiber centers of the adjacent optical fibers within predetermined lateral center-to-center spacing tolerances along the length of the at least one spacer fiber; and

an encapsulation layer fabricated from a second material supporting the optical fibers and the at least one spacer fiber in their predetermined relative positions, the second and third materials being at least one of (i) respectively more soluble than the first material in a first solution and a second solution and (ii) more soluble in a common solution than the first material from which the optical fibers are fabricated.

2. The optical fiber cable of claim 1 wherein the optical fibers are insoluble in the first and second solutions.

3. The optical fiber cable of claim 1 wherein the optical fibers are insoluble in the common solution.

4. The optical fiber cable of claim 1 wherein the optical fibers and the at least one spacer fiber within the at least one connectorization region are ribbonized such that the optical fiber centers and the spacer center of the at least one spacer fiber are normally maintained in a substantially planar orientation in the lateral direction, but flexible in at least the longitudinal direction.

5. The optical fiber cable of claim 1 wherein the center-to-center spacings maintained between adjacent optical fibers within the at least one connectorization region correspond to the center-to-center spacings of the fiber-receiving channels of a multifiber terminal connector with which the optical fiber cable is to be connectorized.

6. The optical fiber cable of claim 1 wherein the optical fiber cable is an optical fiber ribbon cable and the at least one connectorization region is a single connectorization region that extends over the entire length of the optical fiber cable.

7. The optical fiber cable of claim 1 wherein the optical fiber cable is an optical fiber ribbon cable including at least two connectorization regions in which the adjacent optical fibers and the at least one spacer fiber are precisely ribbonized so as to maintain the fiber centers within the predetermined lateral center-to-center spacing tolerances and an intermediate region between the at least two connectorization regions in which the optical fibers are imprecisely ribbonized such that they are not intentionally maintained within predetermined lateral center-to-center spacing tolerances and wherein the encapsulation layer extends over the at least two connectorization regions and the intermediate region.

8. The optical fiber cable of claim 7 further including indicia distinguishing the at least two connectorization regions from the at least one intermediate region to assist persons in identifying an appropriate location for connectorization of the optical fiber cable with a multifiber terminal connector.

9. The optical fiber cable of claim 1 including at least two connectorization regions in which the adjacent optical fibers and the at least one spacer fiber are precisely ribbonized so as to maintain the fiber centers within the predetermined lateral center-to-center spacing tolerances and an unribbonized region between the at least two connectorization regions in which the optical fibers are not ribbonized and not intentionally maintained within predetermined lateral center-to-center spacing tolerances.

10. The optical fiber cable of claim 9 wherein the optical fibers within the unribbonized region are at least one of (i) randomly arranged and sheathed, (ii) randomly arranged and unsheathed, (iii) sheathed and purposely arranged in an other-than ribbonlike configuration and (iv) unsheathed and purposely arranged in an other-than ribbonlike configuration.

11. The optical fiber cable of claim 1 including at least two spacer fibers wherein each spacer fiber within the at least one connectorization region is one of a first color and a second color and the spacer fibers are arranged in one of a prescribed plurality of color combinations in accordance with a predetermined coding system in which each of the prescribed color combinations of spacer fibers is indicative of an optical fiber cable having a unique set of characteristics.

12. The optical fiber of claim 11 further including a fiducial spacer fiber positioned laterally to the outside of an outermost optical fiber in the at least one connectorization region to orient the at least one connectorization region.

13. The optical fiber cable of claim 1 wherein each spacer fiber within the at least one connectorization region is one of a three or more colors and the spacer fibers are arranged in one of a prescribed plurality of color combinations in accordance with a predetermined coding system in which each of the prescribed color combinations of spacer fibers is indicative of an optical fiber cable having a unique set of characteristics.

14. The optical fiber of claim 13 further including a fiducial spacer fiber positioned laterally to the outside of an outermost optical fiber in the at least one connectorization region to orient the at least one connectorization region.

15. The optical fiber cable of claim 1 wherein the encapsulation layer comprises at least one of (i) at least one adhesive tape layers, (ii) an adhesive coating layer, (iii) an epoxy coating layer, (iv) a plastic deposition (v) thermoplastic adhesive, and (vi) a radiation-curing adhesive.

16. The optical fiber cable of claim 1 wherein the second material from which the encapsulation layer is made is the same material from which the at least one spacer fiber is made.

17. A method of connectorizing a multifiber terminal connector to an optical fiber cable comprising the steps of:

providing a multifiber terminal connector adapted for terminating an optical fiber ribbon cable and having a plurality of spaced fiber-receiving channels for receiving and supporting a corresponding plurality of optical fibers;

providing an optical fiber cable having at least one connectorization region in which at least two adjacent optical fibers having fiber centers are maintained with their fiber centers separated by a distance that is within predetermined center-to-center spacing tolerances by at least one spacer fiber abuttingly positioned between the adjacent optical fibers, the optical fibers and the at least one spacer fiber being normally supported in a generally planar configuration by an encapsulation layer, the optical fibers, encapsulation layer and the at least one spacer fiber being fabricated from first, second and third materials respectively;

providing an end surface generally perpendicular to the fiber axes within a connectorization region of the at least one connectorization regions;

leaching a section of the connectorization region beginning at the end surface and extending along the connectorization region for a leach-depth in one of (i) a single, common solution that will dissolve both the second and third materials from which the encapsulation layer and the spacer fibers are fabricated, but not the first material from which the optical fibers are fabricated and (ii) a first solution that will dissolve the encapsulation layer and a second solution that will dissolve the spacer fibers, but neither of which first and second solutions will dissolve the optical fibers, such that there remain exposed fiber segments of the at least two optical fibers protruding from an unleached remainder of the connectorization region;

inserting the protruding fiber segments into corresponding fiber-receiving channels of the multifiber terminal connector; and

securing the optical fiber segments within their corresponding fiber receiving channels.

18. The method according to claim 17 wherein the step of providing an end surface further includes providing an optically smooth end surface prior to leaching a section of the connectorization for a leach-depth.

19. A method of fabricating an optical fiber cable having at least one ribbonized connectorization region for connectorizing with a multifiber terminal connector comprising the steps of:

providing a plurality of optical fibers for inclusion within the optical fiber cable, each of which has a fiber center, a fiber height and a predetermined optical fiber width, the optical fibers being fabricated from a first material;

predetermining the desired center-to-center spacing that adjacent optical fibers are to have within the at least one connectorization region;

providing at least one spacer fiber fabricated from a third material for positioning in abutting relationship between first and second adjacent optical fibers within the plurality of optical fibers such that, with respect to each set of first and second adjacent optical fibers to be spaced apart, one half the optical fiber width of the first optical fiber plus one half the optical fiber width of the second optical fiber plus the sum of the spacer fiber widths of the at least one spacer fiber to be abuttingly positioned between the first and second optical fibers is equal to the predetermined center-to-center spacing within a connectorization region;

arranging and temporarily restraining the first and second optical fibers of each set of adjacent optical fibers to be spaced apart in lateral abutting relationship with at least one spacer fiber positioned therebetween such that the center-to-center spacing between the first and second optical fibers is within acceptable predetermined tolerances over some length along the at least one spacer fiber; and

applying an encapsulation layer comprising a second material to the restrained optical fibers and the at least one spacer fiber to form a connectorization region in which the optical fibers and the at least one spacer fiber are supported by the encapsulation layer in abutting relationship, the second material from which the encapsulation layer is fabricated being more soluble in a first solution than the first material and the third material from which the spacer fibers are fabricated being more soluble in a second solution than the first material.

20. The method of claim 19 wherein the first and second solutions are the same.

21. The method of claim 19 wherein the second material from which the encapsulation layer is made is the same as the third material from which the at least one spacer fiber is made.