An optical fiber that includes a central core having a maximum dimension (A) greater than a minimum dimension (B), preferably with an aspect ratio greater than 1.5, the fiber having at least one air hole positioned on opposite sides of the central core and extending along the fiber's length wherein the fiber supports a single polarization mode within an operating wavelength band. The fiber may be coupled to optical components in systems to provide single polarization in the band. A method for manufacturing the fiber is also provided.