A single mode optical waveguide fiber designed for high data rate, or WDM systems or systems incorporating optical amplifiers. The optical waveguide has a compound core having a central region and at least one annular region surrounding the central region. A distinguishing feature of the waveguide core is that the minimum refractive index of the central core region is less than the minimum index of the adjacent annular region. A relatively simple profile design has the characteristics of ease in manufacturing together with flexibility in tailoring Dw to yield a preselected zero dispersion wavelength, dispersion magnitude over a target wavelength range, and dispersion slope. The simplicity of profile gives reduced polarization mode dispersion.