Abstract

Optical fiber based filters are attractive for applications in optical communications, nonlinear switching, and sensing primarily because of their potential for low loss and large interaction lengths. We describe a fiber filter that is based on resonant coupling of the spatial modes in a two-mode fiber. Two-mode fiber devices based on such coupling have been investigated.^1,2 However, the wavelength dependence of the coupling and its potential for use in fiber filters have not yet been demonstrated. Here we describe a novel resonant-helix geometry for coupling the modes in a two-mode fiber and demonstrate its use in a low loss, high efficiency notch filter.

© 1990 Optical Society of America