Supermode resonances in a multi-core holey fiber-based sensor Vasile A. Popescu, Niculae Tiberiu Puscas and Guido Perrone Eur. Phys. J. D, 68 8 (2014) 229 Published online: 12 August 2014 DOI: 10.1140/epjd/e2014-50297-9