Grating-type optical filter with apodised spectral response

摘要

A device is presented that is adapted to have an optical wave travel through it and to filter that wave in terms of wavelength, in which an optical parameter of the device varies along the path of the wave in such a manner that the device has a series of sections each constituted by a pair of two successive segments, one in which the values of the optical parameter are less than an average value and the other in which the values of the optical parameter are greater than the average value. The device has at least one zone of more than two sections. The two sections have lengths alternately less than and greater than an average length of the sections in that zone.