Intermodal interferences in a multimode highly asymmetric two-core microstructured optical fiber

We investigate intermodal beatings in a multimode highly asymmetric two-core microstructured optical fiber. The modal interference theory plus finite-element calculations are used to define the expected spectral signature-beat length versus propagation length-of inter-and intra-core beating. The corresponding experimental data are in excellent agreement with these predictions over 2 orders of magnitude of the propagation length. The analysis of a similar single-core fiber confirms the identification of the beatings. Therefore, a simple framework can provide an adequate picture of propagation in complex multicore microstructured fibers. (C) 2010 Optical Society of America