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ConferencesWSOF2013, Sigtuna, Sweden, August 2013 Poster presentation: Helically twisted solic-core photonic crystal fibers
Current research / employment Helically twisted solid-core photonic crystal fibers (PCFs) are experimentally and theoretically investigated. These fibers have been successfully fabricated using both a postprocessing technique and directly from a fiber drawing tower. It has been demonstrated for the first time that the core mode of a twisted endlessly single-mode PCF exhibits circular birefringence, despite there being no linear birefringence in the untwisted fiber. In spectral regions where there are no transmission dips, the magnitude of the observed circular birefringence increases linearly with twist rate. Theoretical analysis based on symmetry properties and perturbation theory showed that both spin and orbital angular momentum (OAM) of light play a role in the phenomenon. Tuning of transmission dips, which are associated with the formation of OAM states in the helical cladding, with mechanical strain and twist has been experimentally demonstrated. Analysis shows that the tension-induced shift in resonance wavelength is determined both by the photoelastic effect and by the change in twist rate, while the torsion-induced wavelength shift depends only on the change in twist rate. A twisted PCF with a special three-bladed propeller-like core has been developed and shown to support guided modes carrying OAM. It has been experimentally demonstrated that the sign of the OAM is preserved after 50 m of fiber. A highly instructive model based on helical Bloch waves has been developed to explain the underlying physics of these modes.
Publications X. M. Xi, G. K. L. Wong, M. H. Frosz, F. Babic, G. Ahmed, X. Jiang, T. G. Euser, and P. St.J. Russell, Orbital-angular-momentum-preserving helical Bloch modes in twisted photonic crystal fiber, Optica, 1, 165-169, (2014)

T. Weiss, G. K. L. Wong, F. Biancalana, S. M. Barnett, X. M. Xi, and P. St.J. Russell, Topological Zeeman eect and circular birefringence in twisted photonic crystal bers, J. Opt. Soc. Am. B, 30, 2921-2927, (2013)

X. M. Xi, T. Weiss, G. K. L. Wong, F. Biancalana, S. M. Barnett, M. J. Padgett, and P. St. J. Russell, Optical activity in twisted solid-core photonic crystal fibers, Phys. Rev. Lett., 110, 143903, (2013)

Xiaoming Xi, Gordon K. L. Wong, Thomas Weiss, and Philip St.J. Russell, Measuring mechanical strain and twist using helical photonic crystal fiber, Optics Letters, 38, 5401-5404, (2013)