VARIABLE-SPECTRAL-RESPONSE OPTICAL WAVE-GUIDE BRAGG GRATING FILTERS FOR OPTICAL SIGNAL-PROCESSING

A simple method is described that permits the spectral response (spect ral width, shape, and center resonant wavelength) of an optical wavegu ide Bragg grating to be controlled accurately in a prescribed manner. The control methodology consists of bonding the Bragg grating along th e length of a mechanical support structure, which is then loaded with an appropriate force distribution. The function of the support structu re is to transfer the strain induced by loading to the grating, thus m odifying the grating's spectral response in accordance with the variat ion in effective optical pitch induced by the strain transfer. We desi gn and demonstrate a support structure that provides independent contr ol over the spectral width and center wavelength of a Bragg grating.