Narrow-band in-line fiber filter using surface-guided Bloch modes supported by dielectric multilayer stacks

Surface-guided Bloch modes (SGBMs) confined to the interface between a dielectric multilayer stack and an external medium are highly dispersive with wavelength. This makes attractive their use in a filter configuration based on evanescent coupling between two dissimilar guides. The coupling between a fiber mode and a SGBM is modeled theoretically, predicting a narrow bandwidth for small coupling lengths.