Patent ID: 7946133

Claim:
A method of modifying the cross-section shape of a generally cylindrical optical core rod, the method comprising: providing a core rod comprising a core and a layer of cladding material surrounding the core, wherein a cross-section shape of the core is substantially oval along a length of the core rod; mounting the core rod on a lathe having a first rotor attached to one end of the core rod and a second rotor attached to an opposite end of the core rod; scanning the core rod to measure the cross-section shape of the substantially oval core; preferentially etching the core rod with a plasma torch to alter an outside diameter of the cladding layer to substantially match the cross-section shape of the substantially oval core; rotating the core rod by spinning the rotors in the same direction at substantially the same angular velocity; creating a phase shift between the first and second rotors by varying the angular velocity of at least one of the rotors; and alternating the phase shift between clockwise and counterclockwise directions to perturb the substantially oval core and redistribute the core to a more circular shape, wherein the etching of the core rod comprises rotating the core rod at a rotational velocity that varies as a function of the measured cross-section shape of the substantially oval core as the core rod is etched.