title: Highly birefringent optical microfibers.
abstract: Highly birefringent (Hi-Bi) air-clad silica microfibers (MFs) with wavelength and sub-wavelength scale transverse dimensions are studied theoretically and experimentally. Hi-Bi MFs are taper-drawn from the standard SMF-28 single mode fibers that are "pre-processed" by "cutting away" parts of the silica cladding on opposite sides of the fiber with a femtosecond infrared laser. Such Hi-Bi MFs have approximately elliptical cross-sections and are approximated by a three-layer model comprising a small central Ge-doped region surrounded by an elliptical silica region and an air-cladding. Theoretical modeling shows that phase and group birefringence of the order 10(-2) can be achieved with such air-clad Hi-Bi MFs. Experiments with an air-clad elliptical fiber with a major diameter of 0.9 microm and a minor/major diameter ratio of 0.9 demonstrated a group birefringence of approximately 0.015, agreeing well with the theoretical predictions. The Hi-Bi MFs are useful for micron/nanoscale polarization maintaining transmission and phase-sensitive interferometric sensors.
authors.affiliation: Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Xuan
authors.forename: Jian
authors.initials: J
authors.lastname: Ju
authors.forename: Wei
authors.initials: W
authors.lastname: Jin
mesh_terms: D001718:Birefringence; D003198:Computer Simulation; D017076:Computer-Aided Design; D008027:Light; D008904:Miniaturization; D008962:Models, Theoretical; D055100:Optical Fibers; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation