Low bend loss singlemode optical waveguide fiber

Abstract From the Canadian patent

An optical waveguide fiber with improved bend loss performance while maintaining cutoff wavelength .lambda.c, and zero, dispersion wavelength .lambda.o, in practical operating ranges. The fiber includes an inner core region with a refractive index delta higher than the rest of the core and a reduced diffusion tail at the core/cladding interface. Optionally a, ring at the outer portion of the core is provided to compensate for increased .lambda.o which results from the higher inner core refractive index delta. This ring also contributes to the reduced diffusion tail at the core/cladding interface.