Hybrid photonic-crystal fiber for single-mode phase matched generation of third harmonic and photon triplets

All-fiber systems for third harmonic generation are of great interest because they can be used for the inverse process, namely, the generation of entangled photon triplets. Usually, chromatic dispersion prevents phase matching between the incident and generated radiation when they are both guided in an LP01-like mode. Here, we present a hybrid photonic crystal fiber that has been designed for phase matched third harmonic generation from 1596 to 532 nm in single-lobed modes. The third harmonic radiation is guided by an all-solid bandgap microstructure, while the pump frequency is confined by conventional total internal reflection. The fiber is also suitable for the generation of photon triplet states.