Fabrication and characterization of chalcogenide polarization-maintaining fibers based on extrusion

The fabrication and characterization of IR chalcogenide polarization-maintaining (PM) step-index optical fibers with elliptical-core and 1-in-line-core have been reported for the first time. An improved isolated co-extrusion method was used to fabricate these core-shaped PM fibers. The elliptical core had a horizontal radius of a = 3.66 μm, vertical radius of b = 1.83 μm and the 1-in-line core of a = 4.83 μm, b = 1.42 μm, respectively. Single-mode PM beam spots were observed for the elliptical-core and 1-in-line-core fibers in the near-field energy distributions. The highest values of birefringence of the elliptical-core and 1-in-line-core fibers are 2.09 × 10−4 at 2.7 μm and 3.272 × 10−4 at 2.8 μm, respectively. The extinction ratios of −3.7 dB and −2 dB were achieved in fibers of 0.5 m long with elliptical-core and 1-in-line-core, respectively.