Polarization-Maintaining Large-Mode-Area Microstructured-Core Optical Fibers

A novel polarization-maintaining large-mode-area optical fiber is proposed in this paper. Anisotropic microstructured core in the fiber is realized by the inclusion of air holes arranged in rectangular lattice. An updoped silica background is introduced to compensate the reduction of the effective core index induced by the air holes. Numerical investigation demonstrated high birefringence on the order of 10^-3 and hexagonal profile mode fields with mode areas as large as of 161.2 and 118.0 mum², at the wavelength of 1.55 mum, for x- and y-polarized states, respectively, can be achieved in one such fiber. In contrast to polarization-maintaining optical fibers reported previously, the birefringence of the fiber is increasing with the increase of frequency. We also proposed a novel kind of single-polarization single-mode optical fibers based on the design, and one such fiber presents mode area as large as 119 mum² and operating wavelength as broad as 127 nm with confinement loss below 0.1 dB/km.