Impact of geometrical parameters on optical properties of negative   curvature hollow-core fibers
  We analyze the impact of geometrical parameters on such important optical characteristics of negative curvature hollow-core fibers (NCHCFs) as waveguide dispersion, waveguide losses and the structure of transmission bands. We consider both theoretically and experimentally the resonance effects and formation of band edges under bending in NCHCFs. 
G.K. Alagashev, A. D. Pryamikov, A.F. Kosolapov, A. N. Kolyadin, A.Yu.   Lukovkin, and A.S .Biriukov
physics.optics