Sensitivity analysis of narrow-band photonic crystal filters and waveguides

Photonic band gap materials attract much attention in the context of designing optical and microwave devices. Line defects in photonic crystals can be used to guide optical signals and also to multiplex and demultiplex them (see Centeno, E., 1999). A new guiding device with a prescribed center frequency and narrow bandwidth - the coupled cavity waveguide (CCW) - has been proposed recently (see Bayindir, M. et al., 2000; Yariv, A. et al., 1999; Boag, A. and Steinberg, B.Z., 2001). In these devices, a waveguide is formed by widely spaced periodic defects in the photonic crystal. Each defect site with a resonant frequency in the band gap serves as a microcavity. Tunneling of radiation between the defect sites allows wave propagation along the line of defects. Sections of such waveguides can be employed as ultra narrow band filters in optical routing devices in communication applications where the operating wavelengths are in the 1.5 μm regime. We examine sensitivity aspects related to the microcavity frequency and the ramifications of these effects on the CCW filter design.