Method and apparatus for determining index of refraction profiles of optical fibers

Claim 5

The light projecting method of claim 2 wherein the fiber is positioned so as to extend through the photodetector passageway, and wherein said fiber end is illuminated by a second beam of light directed into the other fiber end and through the fiber.

Claim 6

Apparatus for use in determining the index of refraction profile of an optical fiber and with the apparatus comprising, in combination, a photodetector having a passageway therethrough, means for positioning an end of the fiber adjacent said photodetector, and means for passing a beam of light focused on the fiber end through an end portion of the fiber and then partially onto said photoconductor about said passageway and partially through said passageway whereby leaky modes of light radiating in an inner portion of the beam as it conically diverges from the fiber end pass through rather than strike the photodetector.

Claim 7

Apparatus for use in determining the index of refraction profile of an optical fiber and with the apparatus comprising, in combination, a photodetector having a passageway therethrough, means for positioning an end of the fiber adjacent said photodetector, and means for passing a beam of light focused on the fiber end through an end portion of the fiber and then partially onto said photoconductor about said passageway and partially through said passageway whereby leaky modes of light radiating in an inner portion of the beam as it conically diverges from the fiber end pass through rather than strike the photodetector.

Claim 8

Apparatus in accordance with claim 4 wherein said fiber positioning means includes a tank housing an index of refraction matching oil bath in which the fiber end is submerged.

Claim 9

Apparatus in accordance with claim 5 wherein said tank has a floor at least a portion of which is transparent, and wherein said fiber positioning means further includes a scanning stage upon which said tank is supported having a light passageway therethrough over which said tank transparent floor portion is positioned.

Claim 10

Apparatus in accordance with claim 5 or 6 wherein said tank has a cap at least a portion of which is transparent through which transparent portion fiber mounting means extend.

Claim 11

Apparatus for projecting radiant energy indicative of light transmitting characteristics of an optical fiber for use in determining the index of refraction profile of the fiber and with said apparatus comprising a photodetector having a centrally located passageway therethrough; a scanning stage mounted for relative movement beneath said photodetector; a tank housing an index of refraction matching oil bath supported upon said scanning stage beneath said photodetector; means for holding an optical fiber with a fiber end within said tank submerged in said oil bath; and means for passing a beam of radiant energy focused on an end of an optical fiber held by said holding means through said fiber end and onto said photodetector with a portion of said beam passing through said photodetector passageway.

Claim 12

Apparatus for projecting radiant energy indicative of light transmitting characteristics of an optical fiber for use in determining the index of refraction profile of the fiber and with said apparatus comprising a photodetector having a centrally located passageway therethrough; a scanning stage mounted for relative movement beneath said photodetector; a tank housing an index of refraction matching oil bath supported upon said scanning stage beneath said photodetector; means for holding an optical fiber with a fiber end within said tank submerged in said oil bath; and means for passing a beam of radiant energy focused on an end of an optical fiber held by said holding means through said fiber end and onto said photodetector with a portion of said beam passing through said photodetector passageway.

Claim 13

Light projecting apparatus in accordance with claim 8 wherein said fiber holding means includes means for holding the optical fiber in a position extending through said photodetector passageway.