Interband scattering in a slow light photonic crystal waveguide under electro-optic tuning

The evolution of the transmission spectrum of a photonic crystal waveguide under electro-optic tuning was studied in the band of an odd TE-like mode. The spectral signature of the interband scattering from the TM-like mode to the odd TE-like mode was characterized at various bias levels. The shift of the odd-mode band was determined based on a statistical approach to overcome the spectral noise. Simulations were performed to explain the spectral shift based on electro-optic and thermo-optic effects in the active photonic crystal structures. Potential impact of interband scattering on indirect interband-transition-based optical isolators is discussed and potential remedies are offered.