Polarization-maintaining photonic crystal fiber with rim-touched defect-holes

To achieve a polarization-maintaining photonic crystal fiber (PM-PCF) with ultra-high modal birefringence, four types of PM-PCF structure, Traditional, Rim-Touched −4 and −5 (RTS-4 and RTS-5) and Air-Walls structures (AWS), are investigated and compared with each other. A compromising structure with higher birefringence, lower loss and feasibility can be chosen by means of numerical analysis. From the simulation results, the birefringence of the designed RTS-4 PM-PCF with a confinement loss of only about 0.395 dB/km is up to 13.22×10−3 at λ=1.55 μm. Finally, two imperfect conditions of broken wall and thicker wall in the drawing process are investigated to prove that the proposed structure is practicable.