Patent ID: 8194320

Claim:
A method of designing a multi-channel grating structure having at least one specified spectral characteristic in a photosensitive material, the multi-channel grating structure having at least one free spectral characteristic which is not a specified spectral characteristic, the method including: a) storing an initial value for the at least one free spectral characteristic on a computer-readable medium; b) utilizing a computer processor connected to the computer-readable medium to determine an initial multi-channel grating function that describes an initial multi-channel grating structure by applying a spectral to spatial domain algorithm to the at least one specified spectral characteristic using the at least one initial value; c) storing on a computer readable medium a target multi-channel grating function which describes a target multi-channel grating structure in the photosensitive material; d) utilizing the computer processor to determine an updated value for the at least one initial value with reference to the spectral characteristics of the target multi-channel grating function; e) utilizing the computer processor to determine an updated multi-channel grating function which describes an updated multi-channel grating structure in the photosensitive material by applying the spectral to spatial domain algorithm to the at least one specified spectral characteristic using the at least one updated value; and f) utilizing the computer processor to generate an output, after at least one iteration of a) to e), of the updated multi-channel grating function to describe the multi-channel grating structure having non-identical spectral channels and/or non-equidistant channel spacing.