A modified coupled-mode (CM) model is proposed for the optical behavior of thermally chirped Bragg gratings. The model accounts for the axial gradient in the modulation wavenumber, which has been ignored in the classical CM model. The model is used to characterize the optical behavior of a polymethyl methacrylate-based polymer Bragg grating subjected to nonisothermal conditions. The validity of the proposed method is verified by comparing the results of the modified CM model with those obtained from the exact numerical solution.
© 2010 Optical Society of America
Diffraction and Gratings
Original Manuscript: October 30, 2009
Revised Manuscript: March 5, 2010
Manuscript Accepted: March 6, 2010
Published: April 5, 2010
Ilai Sher, Bongtae Han, and Avram Bar-Cohen, "Modified coupled-mode model for thermally chirped polymer Bragg gratings," Appl. Opt. 49, 2079-2084 (2010)