Optical fiber distribution module

Abstract: An optical fiber distribution module (80) has a panel (82) formed with a plurality of parallel lands (84) having undercuts for releasably attaching a plurality of optical fiber connectors (20), each of which forms a bridge across the panel. The lands (84) have sufficient length to permit two of the connectors to be attached to the same lands with a jacketed optical fiber from each of said connectors passing beneath the bridge defined by the other connector. When a large number of the connectors are attached to the panel, the passage of some optical fibers beneath such bridges helps to organize, route, and identify the interconnected optical fibers.

Description: Cross-Reference to Related Application A coassigned European Patent Application No. 92300899.9 discloses a preferred optical fiber connector for use in the optical fiber distribution module of the invention. Its disclosure is incorporated herein by reference. Background of the Invention Field of the Invention The invention concerns an optical fiber distribution module including a panel on which a plurality of optical fiber connectors are releasably mounted in an orderly manner. Description of the Related Art A number of commercially available patch panels or modules contain a plurality of optical fiber connectors in a one or two rows. See the 24-fiber optical patch panel CPC of Siecor Corp., Hickory, NC; the COFO fiber optic enclosures of Reliable Electric, Franklin Par, IL, that have slide-out shelves; and the distribution centers illustrated in Catalog 86-792 dated 5-87 and entitled "Opticmate Single-Mode Fiber Optic Interconnection System" from AMP., Harrisburg, PA. pages 22 and 23. The latter refers to such modules as "connector organizer trays". See also; U.S. Pat. No. 4,848,870 and EPO Patent Application EP 341,027A published Nov. 8, 1989. In coassigned U.S. Pat. No. 4,824,196 (Bylander), optical fiber connectors are mounted in a single row along one edge of each of a plurality of modules, each of which can be pivoted out of a housing to afford access to the connectors, and then returned to the protection of the housing. Each connector is mounted at an angle such that it can be reached with minimal impediment from optical fibers of adjacent connectors. A relatively inexpensive mechanical optical fiber connector can be constructed as disclosed in coassigned U.S. Pat. No. 4,470,180 (Blomgren). A preferred connector of the Blomgren '180 patent includes an elongated mount that is encompassed by a resiliently deformable housing which, in its relatively undeformed state, can urge a free end of an optical fiber against a straight longitudinal groove in the surface of the mount. Upon squeezing to deform the housing, a free end of a second optical fiber can be removed or inserted to become coaxially interconnected with the first as shown in Fig. 6C of the Blomgren '180 patent. In an improvement of the connector of the Blomgren '180 patent, the elongated mount is a mandrel of substantially uniformly elliptical cross section as disclosed in coassigned U.S. Pat. No. 4,729,619 (Blomgren). An optical fiber connector now on the market ("DORRAN" #07-00060 from 3M) is constructed as taught in both Blomgren patents and also, as in the Blomgren '619 patent, has a strain-relief chock formed with a trough against which the fiber buffer layer can be gripped after being exposed by stripping. The Disclosure of the Above-cited Patent Application EPA No. 92300899.9 discloses an optical fiber connector, which like the DORRAN connector, has a mount encompassed by a resiliently deformable housing. The connector of said application differs from the DORRAN connector in that its housing, or an envelope fitting around the housing, incorporates a pair of flanges that act as second-class levers when squeezed together by ones fingers to deform the housing to receive the free end of an optical fiber or to release it. Summary of the Invention The invention provides an optical fiber distribution module for a plurality of optical fiber connectors, which module in comparison to those discussed above should be no more expensive to manufacture but more convenient to use. For example, it should be feasible to mount and organize, without confusing congestion, a significantly greater number of optical fiber connectors than has been possible with prior modules or patch panels of comparable size. According to this invention there is provided an optical fiber distribution module as claimed in claim 1 herein. Preferred features are defined in the appended claims. When a large number of the connectors are thus attached to the panel, the passage of optical fibers beneath the bridges can help to route, organize, and identify the fibers. The term "optical fiber connectors" is here used to encompass 1) disconnectable mechanical connectors, 2) connectors that cannot be disconnected and generally are called "splices", 3) switches that can interconnect one or more optical fibers with one or more additional optical fibers, and 4) implements for connecting optical fibers to opto-electronic devices. The connectors can conveniently be color coded, as can auxiliary bridging devices, to assist in identifying each of the optical fibers. While being useful with all such connectors, the novel distribution module is particularly useful with mechanical connectors, especially the connector of the above-cited EPA No. 92300899.9 which has a deformable housing, or an envelope around the housing, that incorporates a pair of flanges, the extremities of which can be formed to interlock with raised portions of a panel. In making a connection between a connector and raised portions, the flanges preferably are biased away from each other to make a more secure attachment. This results in a force that causes the housing to press more tightly against a captured element such as an optical fiber, thus better ensuring that the fiber stays in place. The Drawing The invention may be more easily understood in reference to the drawing, each figure of which is schematic. In the drawing: FIG. 1 is an end view of a first optical fiber distribution module of the invention including two of the mechanical connectors of the above-cited patent application; FIG. 2 is a top view of the optical fiber distribution module of FIG. 1 including a large number of the mechanical connectors; FIG. 3 is an end view of a portion of the panel of a second optical fiber distribution module of the invention; FIG. 4 is an end view of a third optical fiber distribution module of the invention including four of the mechanical connectors of the above-cited patent application; FIG. 5 is an end view of a fourth optical fiber distribution module of the invention including one mechanical connector of the above-cited patent application; and FIG. 6 is an isometric view of a fifth optical fiber distribution module of the invention including various optical fiber connectors. Detailed Description of a Preferred Embodiment The optical fiber distribution module 10 of FIG. 1 has a panel 12 formed with a plurality of elongate raised portions 14, the sides of which have undercuts 16. One mechanical optical fiber connector 20 is mechanically attached to the panel, and an identical connector 20A is in position to be attached. Each has an elongated mount 22 which is a mandrel of elliptical cross section. The surface of the mandrel is formed with a longitudinal V-groove 24 of uniform depth in which is seated the bare end 26A of an optical fiber 26. Encompassing the mandrel is a resiliently deformable housing 28 which when undeformed, grips the bare end of the fiber against the mount. Integral with the housing are a pair of flanges 30 that normally extend parallel to each other and act as second-class levers. When squeezed in the direction of the arrows 32 by ones fingers, the flanges deform the housing to release the bare end of the fiber. The flanges are resilient and so flex outwardly to permit protrusions 34 at their extremities to mate with the undercuts 16. By being so flexed, the optical fiber 26 is gripped more tightly by the housing 28. When a plurality of the connectors 20 are attached to the panel 12, each housing 28 and its flanges 30 form a bridge to create a passage 38 through which one or more jacketed optical fibers 26 can pass as indicated in FIG. 2, thus helping to organize and route the optical fibers that extend from the connectors. In FIG. 2, the raised portions and grooves are not shown. Shown in FIG. 3 is a segment of a cylindrical panel 42 having raised portions 43 of a second optical fiber distribution module. The panel 42 can be used with the mechanical optical fiber connectors 20 of FIGS. 1 and 2. The panel is formed with one or more ducts 44 to permit optical fibers to be routed through the cylindrical interior, thus further organizing the fibers. The optical fiber distribution module 50 of FIG. 4 has a panel 52, each side of which is formed with a plurality of raised portions 54 and 55 having undercuts 56 and 57, respectively. One mechanical optical fiber connector 20B is positioned behind another connector 20C, and one flange 30 of each connector fits into the same channel between adjacent raised portions 55. The optical fiber distribution module 60 of FIG. 5 has a panel 62 formed with a plurality of raised portions 64, each of which has undercuts 66 and 68 on its sides. A mechanical optical fiber connector 70 has a pair of flanges 72 that act as second-class levers. The extremities of the flanges are formed with protrusions 74 and 76 that mate with the undercuts 66 and 68, respectively. The optical fiber distribution module 80 of FIG. 6 has a panel 82 formed with a plurality of raised portions 84, each having undercuts on each side. Releasably mounted on the panel 82 are several optical fiber connectors, each of which has a body, a pair of spaced flanges, and means for releasably attaching the spaced flanges to the raised portions at any position along the raised portions. One of those is an optical fiber connector 20 of FIG.1. A second is an implement 86 for connecting an optical fiber (not shown) to an opto-electronic element 87. A third is a switch 88 that can interconnect (by means not shown) either of two optical fibers 90 and 91 to either of two other optical fibers 92 and 93. Also releasably attached to the panel 82 of FIG. 6 is a standoff 100 that has two sets of flanges so that it and other standoffs (not shown) can mount a second panel 102 above the first. The central web of the standoff 100 is cut through at 103 to a living hinge 104, thus permitting the second panel 102 to be pivoted to one side for convenient access to the optical fiber connectors positioned on die first. Each of the standoff 100 and a U-shaped member 106 is an auxiliary bridge-forming device that can cooperate with the connectors 20, 86 and 88 to organize, route, and identify optical fibers emanating from the connectors. Example A prototype of the optical fiber distribution module 10 of FIG. 1 has been made by machining from blocks of polyetherimide resin ("ULTEM" 11000 from GE) both the panel 12 and a number of mechanical optical fiber connectors 20 that differ from each other as follows. One has a continuous flange on each side, hence two levers; one flange of a second connector is divided centrally to form two levers; both flanges of a third connector are divided centrally to form two levers on each side. Each of the connectors 20 and the panel have the following dimensions: envelope of the connectors length 32 mm height 10 mm width 7 mm flange thickness 1.4 mm panel max. width of raised portions 1.37 mm angles of undercuts 45° radius of rounds at top of raised portions 0.38 mm width of lands beneath undercuts 1.22 mm min. spacing between raised portions 1.60 mm height of raised portions 2.54 mm height of raised portions above undercuts 1.14 mm The raised portions and the flanges of each of the connectors were sufficiently resilient such that the connectors were easily attached to and detached from the raised portions of the panel and yet remained securely in place because of a slight spreading of the flanges during attachment. For this reason, the resins or other materials for the panel and connectors should be selected for minimal plastic flow.

Claims: An optical fiber distribution module comprising a panel (12; 52; 62; 82), as well as a plurality of optical fiber connectors (20; 70; 86; 88) releasably attachable to said panel, characterised in that a surface of said panel (12; 52; 62; 82) is formed with a plurality of elongate raised portions (14; 43; 54, 55; 64; 84) spaced from each other and extending parallel to one another along said surface, each one of said plurality of optical fiber connectors (20; 70; 86; 88) is formed with a body (22; 28), a pair of spaced flanges (30; 72) which protrude substantially parallel to each other from said body, and means (34; 74, 76) for releasably attaching the free ends of the spaced flanges of each connector to the longitudinal sides of a same or adjacent raised portions at any selected position along the raised portions, so that the body and flanges of each attached connector form a bridge across the corresponding raised portion or portions, and said elongate raised portions have sufficient length to permit two of the connectors to be attached to the same raised portion or portions with an optical fiber (26, 26A) that is connected to either of said two connectors extending directly from that connector to pass beneath the bridge formed by the other of said two connectors. An optical fiber distribution module as defined in claim 1 wherein said body of one of said connectors comprises a resiliently deformable housing (28) encompassing an elongated mount (22), which resiliently deformable housing can in its relatively undeformed state, optically interconnect two optical fibers (26A) by urging their end portions against a straight longitudinal groove (24) in the surface of the mount. An optical fiber distribution module as defined in claim 2 wherein the flanges (30; 72) contact the housing (28) approximately at the diameter of the mount (22). An optical fiber distribution module as defined in claim 1 wherein each longitudinal side of each of the raised portions (14; 43; 54; 64; 84) is formed with an undercut (16; 56; 57; 66; 68) and said releasably attaching means of each connector comprises at the free end of each flange a protrusion (34; 74, 76) which mates with one corresponding undercut when the connector is attached to the panel. An optical fiber distribution module as defined in claim 4 wherein the protrusions of a given connector mate with undercuts on both sides of the same raised portion. An optical fiber distribution module as defined in claim 4 wherein the protrusions of given connector mate with undercuts of different raised portions.

Inventors: BLOMGREN JACK P, BLOMGREN, JACK P., BLOMGREN, JACK P., C/O MINNESOTA MINING AND
Applicants: MINNESOTA MINING & MFG, MINNESOTA MINING AND MANUFACTURING COMPANY
Application year: 1992
Main classification: G02B6
IPC codes: G02B6