APPARATUS AND METHOD FOR GENERATING AN INTERFERENCE PATTERN TO BE WRITTEN AS A GRATING IN A SAMPLE OF A PHOTOSENSITIVE MATERIAL

摘要

An apparatus and method for generating an interference pattern to be written as a grating in a sample of photosensitive material wherein the interference pattern to be written is tunable using at least two moveable reflectors. An incident UV beam is passed through a phase mask, which functions as a beam splitter. The interference pattern produced by the phase mask is tuned by the reflectors before being incident on the photosensitive material. A Bragg grating is written in the photosensitive material whose Bragg wavelength is determined, in combination with other parameters, by the incident tuned interference pattern. This apparatus and method allow wide tunability of the Bragg wavelength of the gratings formed using the same phase mask.