Patent ID: 6873762

Claim:
An apparatus for fabricating fiber-optic gratings on an optical fiber, said apparatus comprising: a laser adapted to direct a beam of coherent energy along an initial beam path which defines a first axis; a phase mask disposed in the initial beam path for diffracting the beam into a first diffracted beam along a first diffracted beam path and a second diffracted beam along a second diffracted beam path, each of said first and second diffracted beam paths having a component in a second axis perpendicular to the first axis; a cylindrical lens disposed downstream of the phase mask in both said first diffracted beam path and said second diffracted beam paths second diffracted beams to produce first and second diverged beams in first and second diverged beam paths, respectively; and first and second mirrors disposed downstream of said cylindrical lens, for recombining the first and second diverged beams to form an interference field directed to the optical fiber, said first mirror being disposed in the first diverged beam oath and said second mirror being disposed in said second diverged beam path.