Abstract

Air-silica microstructured fibers (ASMF) incorporate air holes within the cladding region that run along the length of the fiber.¹ Recendy there has been renewed interest in such fibers because the microstructured region provides extra degrees of freedom in manipulating mode propagation, which can be exploited in a range of different applications.²⁻⁵ To date, research has primarily focused on understanding the guidance properties of fundamental modes localized in the core region, for example, bend loss, cutoff wavelength, mode field diameter, and dispersion. A broader class of applications for ASMF, which we consider in this paper, is in the design of optical components, such as grating-based filters,⁴ and novel tapered fiber devices.⁵ In these applications, core mode guidance can be associated with total internal reflection in a high-index doped region (e.g. germanium doped core). The microstructure cladding, region is then exploited to manipulate the propagation of higher order cladding modes. And, in the context of tapered fiber devices, ensures a mechanically robust device that can be spliced to standard fiber with low insertion loss enabling dramatic efficient nonlinear process including widely tunable Raman soliton generation.

© 2001 Optical Society of America