An optical fiber, comprising: a central core having a maximum dimension
(A) greater than a minimum dimension (B) and a substantially elliptical
shape, the fiber having at least one air hole positioned each opposite
side of the central core wherein the optical fiber exhibits (i) single
polarization propagation within a single polarization band and (ii)
polarization maintaining property, such that the fiber beat length
normalized at 1550 nm is less than 10 mm; and the polarization
maintaining band is situated within wavelengths which are (a) adjacent to
and below the single polarization band; and (b) above the higher order
mode cutoff wavelength.