Hollow-core fibre frequency standard

The development of high-quality and low-loss hollow-core photonic-crystal fiber (HC-PCF) offers interesting opportunities to develop robust and compact frequency standards. We are pursuing two different types of frequency standards based on HC-PCF: one based on saturation spec-troscopy of iodine [1], and a second based on two-photon spectroscopy of rubidium [2]. In this presentation we will present the progress with the rubidium-loaded fibre.