All-circular hole microstructured fiber with high birefringence and low confinement loss.

An air-silica microstructure optical fiber of ultrahigh birefringence of the order ∼10-2 and low confinement loss is proposed. The birefringence is achieved by axial anisotropy introduced in the fiber geometry by the preferred arrangement of circular air holes of different sizes in the cladding structure. Vital properties of the microstructure fiber, e.g., birefringence, confinement loss, dispersion, and walk-off, have been studied by employing numerical solutions through the finite element method. These findings should be useful for the fabrication of the proposed microstructure optical fiber.