Abnormal Blocking of the Fundamental Guided Wave in a Silicon Waveguide by Weak Tunnel Coupling with Periodic Polymer Strips

We examine the optical wave propagation in a single mode silicon wire waveguide which is coupled by the evanescent field with the multiple periodic strips (segmented waveguide) separated from it by a silica buffer. The numerical modeling by the method of lines (MoL) and by finite different time domain (FDTD) method proves that the weak reflectors with period 1.6 mu m may produce a strong of the transmitting optical wave suppression (blocking) by resonant interaction of a guided mode in the silicon wire with a strong decaying optical leaky mode of the artificial segmented waveguide localized in the fully etched polymer grating placed 300 nm above the silicon wire. This effect is important for studying photonic structures with multiple weak tunnel reflections and could be used for the construction of notch filters with negligible parasitic back reflection.