Expanded Beam Connector Concepts

Abstract

A terminus for a fiber optic cable includes a ferrule. In one embodiment, an optical fiber of the cable passes through a central bore of the ferrule and is attached to a lens seated in a conical or cylindrical seat formed in an end surface of the ferrule by an epoxy. In a second embodiment, an optical fiber of the cable passes through the central bore of the ferrule. Next, a cap sleeve with a lens therein is slid over and attached to the ferrule such that the lens abuts or is attached to the optical fiber. In either embodiment, an inspection slot may optionally be formed in the ferrule and/or the cap sleeve to allow a technician to inspect the state of the attachment and/or abutment and/or spacing of the optical fiber and the lens.

We claim: 
     
         1 . A fiber optic cable apparatus comprising:
 a ferrule having a bore passing from a first end to a second end;   an optical fiber passing through said bore of said ferrule, said optical fiber having a termination end proximate said second end of said ferrule;   a sleeve sized to fit over said second end of said ferrule and directly contact said ferrule for attachment thereto;   a lens within said cap sleeve, wherein said lens resides proximate said second end of said ferrule when said cap sleeve is attached to said ferrule, wherein the portion of said lens that resides proximate said second end of said ferrule includes a flat surface; and   an optical epoxy connecting said termination end of said optical fiber to said lens, such that light exiting said termination end of said optical fiber passes through said optical epoxy prior to entering into said lens.   
     
     
         2 . The fiber optic cable apparatus according to  claim 1 , wherein said ferrule and said cap sleeve are formed of a ceramic material. 
     
     
         3 . The fiber optic cable apparatus according to  claim 1 , wherein said optical fiber is generally cylindrical in shape with a first diameter and said lens is generally spherical in shape, apart from said flat surface, and has a second diameter, which is greater than said first diameter. 
     
     
         4 . The fiber optic cable apparatus according to  claim 3 , wherein said second diameter is at least three times greater than said first diameter. 
     
     
         5 . The fiber optic cable apparatus according to  claim 1 , wherein said lens is formed of a material different from said optical fiber, wherein said material forming said optical fiber has a first index of refraction which is less than 1.6 and said material forming said lens has an index of refraction which is greater than said first index of refraction. 
     
     
         6 . The fiber optic cable apparatus according to  claim 1 , wherein said lens is formed of a material different from said optical fiber, wherein said material forming said lens has a first index of refraction which is greater than 1.5 and a material forming said optical fiber has an index of refraction which is less than said first index of refraction. 
     
     
         7 . The fiber optic cable apparatus according to  claim 1 , wherein said lens is formed of sapphire. 
     
     
         8 . The fiber optic cable apparatus according to  claim 1 , further comprising:
 an inspection slot formed in said cap sleeve proximate said lens which affords a view of an area between said lens and said second end of said ferrule when said cap sleeve is attached to said ferrule.   
     
     
         9 . The fiber optic cable apparatus according to  claim 1 , wherein no portion of said lens within said cap sleeve protrudes past an end face of said cap sleeve. 
     
     
         10 . The fiber optic cable apparatus according to  claim 1 , further comprising:
 a retaining sleeve sized to fit over said first end of said ferrule and directly contact said ferrule for attachment thereto.   
     
     
         11 . The fiber optic cable apparatus according to  claim 10 , wherein said retaining sleeve includes a through slot which affords access to an area adjacent said first end of said ferrule when said retaining sleeve is attached to said ferrule. 
     
     
         12 . The fiber optic cable apparatus according to  claim 1 , further comprising:
 a connector envelope supporting said ferrule and said cap sleeve.   
     
     
         13 . A fiber optic cable apparatus comprising:
 a ferrule having a bore passing from a first end to a second end;   an optical fiber passing through said bore of said ferrule, said optical fiber having a termination end proximate said second end of said ferrule;   a sleeve sized to fit over said second end of said ferrule and directly contact said ferrule for attachment thereto;   a lens within said cap sleeve, wherein said lens resides proximate said second end of said ferrule when said cap sleeve is attached to said ferrule, wherein said lens is a barrel lens; and   an optical epoxy connecting said termination end of said optical fiber to said barrel lens, such that light exiting said termination end of said optical fiber passes through said optical epoxy prior to entering into said barrel lens.   
     
     
         14 . The fiber optic cable apparatus according to  claim 13 , wherein said barrel lens has a generally cylindrical mid-region and includes a first convex surface on a first end of said generally cylindrical mid region. 
     
     
         15 . The fiber optic cable apparatus according to  claim 14 , wherein said barrel lens includes a second convex surface on an opposite, second end of said generally cylindrical mid-region. 
     
     
         16 . The fiber optic cable apparatus according to  claim 15 , wherein said generally cylindrical mid-region has a diameter which is approximately equal to an inner diameter of said cap sleeve. 
     
     
         17 . The fiber optic cable apparatus according to  claim 16 , wherein said barrel lens is attached to said cap sleeve by an epoxy. 
     
     
         18 . The fiber optic cable apparatus according to  claim 17 , wherein a portion of said barrel lens protrudes past an end face of said cap sleeve. 
     
     
         19 . A fiber optic cable apparatus comprising:
 a ferrule having a bore passing from a first end to a second end;   an optical fiber passing through said bore; and   a lens attached to said second end of said ferrule and attached to said optical fiber, wherein said second end includes a recessed seat, and wherein said lens resides in said recessed seat, and wherein said lens has a size which is less than a depth of said recessed seat, such that said lens does not protrude past a plane of said second end of said ferrule, wherein said lens is distanced from an end of said optical fiber and the attachment between said lens and said optical fiber is made by an epoxy having optical characteristics and wherein said lens has an index of refraction which is greater than an index of refraction of said optical fiber.   
     
     
         20 . The fiber optic cable apparatus of  claim 19 , wherein said lens has an index of refraction great than 1.6.