Coupling between the lowest-loss TE<sub>01</sub> modes of two touching hollow-core Bragg fibers is considered with a view to designing a directional coupler. We have found that for fibers with core radii larger than 10 µm one can identify broad frequency ranges in which intermodal coupling strength exceeds supermode radiation losses by an order of magnitude, thus opening the possibility of building a directional coupler. We attribute such unusually strong intermode coupling both to the resonant effects in the intermirror cavity and a proximity interaction between the leaky modes localized in the mirror.
© 2004 Optical Society of America
(060.2280) Fiber optics and optical communications : Fiber design and fabrication
(060.2310) Fiber optics and optical communications : Fiber optics
(060.2340) Fiber optics and optical communications : Fiber optics components
(230.0230) Optical devices : Optical devices
Maksim Skorobogatiy, Kunimasa Saitoh, and Masanori Koshiba, "Resonant directional coupling of hollow Bragg fibers," Opt. Lett. 29, 2112-2114 (2004)