Direct observation of modal hybridization in nanofluidic fiber [Invited]

Hybrid-material optical fibers enhance the capabilities of fiber-optics technologies, extending current functionalities to several emerging application areas. Such platforms rely on integration novel materials into fiber core or cladding, thereby supporting hybrid modes with new characteristics. Here we present experiments that reveal mode interactions within a doped-core silica containing central high-index nanofluidic channel. Compared standard liquid-filled capillary, calculations predict unique properties as result doped core/cladding interface, possessing high power fraction inside and outside Our directly beating pattern in fluorescent liquid resulting from excitation first two linearly polarized this system, being excellent agreement theoretical predictions. The efficient beat such an off-resonance situation distinguishes our device regular directional couplers can benefit applications demand strong coupling between fundamental- higher-order- modes, e.g. intermodal third-harmonic generation, bidirectional coupling, sensing.