FABRICATION OF OPTICAL WAVEGUIDE GRATINGS

摘要

Optical grating fabrication apparatus comprises a phase mask (40) for dividing an incident light beam (30) into a plurality of diffracted beams; and a focusing arrangement (60) for receiving light from the phase mask and converging at least two non-zero-order diffracted beams together so as to generate an interference region between the converged beams so that a grating structure can be impressed on an optical waveguide (80) placed in the interference region; the phase mask and at least a part of the focusing arrangement being moveable with respect to one another so as to alter the angle of convergence of the converged beams.