Intermodal interference in a photonic crystal fibre.

Intermodal interference in photonic crystal fibres, single mode over long lengths, is measured over a short length. Akin to conventional fibres, this poses a potential problem for practical device utilisation of photonic crystal fibres. We note that given the existing widespread fabrication capability of this fibre and indications that some commercial use in devices will come to fruition, the need for standardising measurement techniques, analogous to ITU standards for conventional fibre, specific to photonic crystal fibres will be required.