Retractable optical fiber assembly

Abstract

A retractable optical fiber assembly includes a housing, a spool rotatably disposed within the housing and an optical waveguide reeled onto the spool. The optical waveguide has a central length of unjacketed optical fiber and shorter end lengths of jacketed optical fiber terminating in optical connectors. The optical waveguide is reeled onto the spool such that the end lengths of jacketed optical fiber are extracted off the spool and retracted onto the spool in the same direction. The spool is biased in a first rotational direction relative to the housing by a torsion spring that exerts a retracting force on the jacketed optical fiber. A mechanical stop is also provided to prevent rotation of the spool in a second rotational direction opposite the first rotational direction. In an exemplary embodiment, the assembly is a test fiber box for use with optical test equipment to test an optical network.

1 . A retractable optical fiber assembly comprising: 
 a housing;    a spool rotatably disposed within the housing; and    an optical waveguide reeled onto the spool, the optical waveguide comprising a predetermined length of unjacketed optical fiber and a predetermined length of jacketed optical fiber wound radially outwardly of the unjacketed optical fiber.    
   
   
       2 . The retractable optical fiber assembly of  claim 1  wherein the housing surrounds the spool and includes an exit port through which the jacketed optical fiber is extracted and retracted.  
   
   
       3 . The retractable optical fiber assembly of  claim 1  wherein the unjacketed optical fiber forms a central length of the optical waveguide and the jacketed optical fiber forms the opposite end lengths of the optical conductor.  
   
   
       4 . The retractable optical fiber assembly of  claim 3  further comprising an optical connector terminated to each of the end lengths of the optical waveguide.  
   
   
       5 . The retractable optical fiber assembly of  claim 3  wherein a curved channel is formed on an exterior face of the spool and wherein the central length of the optical waveguide is positioned within the channel, the channel reversing the direction of travel of the central length of the optical waveguide relative to the spool.  
   
   
       6 . The retractable optical fiber assembly of  claim 1  wherein the optical waveguide comprises a continuous optical fiber having a central length of unjacketed optical fiber and a pair of end lengths of jacketed optical fiber.  
   
   
       7 . The retractable optical fiber assembly of  claim 1  further comprising torsion spring means operably positioned between the housing and the spool, the jacketed optical fiber being biased on the spool by a retracting force exerted by the torsion spring means.  
   
   
       8 . The retractable optical fiber assembly of  claim 7  further comprising a mechanical stop for preventing rotation of the spool.  
   
   
       9 . The retractable optical fiber assembly of  claim 8  wherein the mechanical stop is releasable for extracting the jacketed optical fiber from the housing and for retracting the jacketed optical fiber into the housing.  
   
   
       10 . The retractable optical fiber assembly of  claim 1  wherein the housing defines an exit port through which the jacketed optical fiber is extracted and retracted and wherein the retractable optical fiber assembly further comprises a cover movably mounted on the housing to open and close the exit port.  
   
   
       11 . The retractable optical fiber assembly of  claim 10  wherein the optical waveguide is completely enclosed within the housing when the cover is in a closed position and wherein the jacketed optical fiber is accessible when the cover is in an open position.  
   
   
       12 . The retractable optical fiber assembly of  claim 1  wherein mandrel channels are located on an exterior face of the spool, the mandrel channels comprising means for reducing the amplitude of higher-order modes propagating in a cladding region of a multimode optical fiber.  
   
   
       13 . The retractable optical fiber assembly of  claim 1  wherein the jacketed optical fiber is strain relieved to the spool.  
   
   
       14 . The retractable optical fiber assembly of  claim 1  wherein the spool is rotatably disposed in a cylindrical cavity formed in the housing.  
   
   
       15 . A retractable optical fiber assembly comprising: 
 a housing defining an interior cavity and an exit port;    a spool rotatably disposed on the housing within the interior cavity; and    an optical waveguide reeled onto the spool, the optical waveguide having a central portion comprising a predetermined length of unjacketed optical fiber and a pair of end portions comprising predetermined lengths of jacketed optical fiber wound radially outwardly of the unjacketed optical fiber; and    wherein the end portions of jacketed optical fiber are extracted off the spool and retracted onto the spool through the exit port.    
   
   
       16 . The assembly of  claim 15  wherein both end portions of jacketed optical fiber are wound on the spool in the same direction.  
   
   
       17 . The assembly of  claim 15  further comprising means for exerting a biasing force for retracting the end portions of jacketed optical fiber onto the spool and a mechanical stop for preventing rotation of the spool, the mechanical stop being releasable to permit the end portions of jacketed optical fiber to be extracted off the spool against the biasing force.  
   
   
       18 . A test fiber box for testing an optical network, the test fiber box comprising: 
 an optical waveguide reeled onto a rotatable spool, a central portion of the optical waveguide comprising an unjacketed optical fiber and a pair of end portions of the optical waveguide comprising jacketed optical fiber having an optical connector terminated to the free end thereof, rotation of the spool in a first direction extracting the jacketed optical fiber and connectors off the spool for connection between optical test equipment and the optical network, rotation of the spool in a second direction opposite to the first direction retracting the jacketed optical fiber onto the spool for storage within the test fiber box.    
   
   
       19 . The test fiber box of  claim 18  further comprising a housing defining an interior cavity, the spool rotatably disposed within the interior cavity and biased in the second direction relative to the housing.  
   
   
       20 . The test fiber box of  claim 18  wherein the jacketed optical fiber is strain relieved to the spool so that the unjacketed optical fiber is not extracted off the spool when the spool is rotated in the first direction.  
   
   
       21 . The test fiber box of  claim 18  wherein the spool has a curved channel formed on an exterior face and wherein the unjacketed optical fiber is positioned within the channel so that the direction of travel of one end of the unjacketed optical fiber is reversed.  
   
   
       22 . The test fiber box of  claim 21  wherein the channel has a radius of curvature at least equal to the minimum bend radius of the unjacketed optical fiber.  
   
   
       23 . The test fiber box of  claim 22  wherein the optical waveguide comprises a single mode optical fiber.  
   
   
       24 . The test fiber box of  claim 18  wherein the optical waveguide comprises a multimode optical fiber and wherein an exterior face of the spool has mandrel wrap channels comprising means for reducing the amplitude of higher-order modes propagating in a cladding region of the multimode optical fiber.  
   
   
       25 . The test fiber box of  claim 18  wherein the optical waveguide has a length of not more than about 1000 meters.