Optics integrated compact cavity for rubidium atomic frequency standards

Abstract

A compact magnetron cavity having integrated optics is designed and realized for a rubidium atomic clock that is being developed for the Indian Regional Navigation Satellite System. This cavity comprises a cylindrical dielectric cell with 25 mm diameter and 25 mm height. The cavity is designed to resonate at the rubidium hyperfine ground-state frequency of 6.8346 GHz with TE011-mode. A loop gap resonator structure is employed to obtain the required uniform mode along the quantization-axis in the cavity. The cutoff frequency of the cavity is designed in such a way that the influence of optics on the cavity mode is negligible and it is well within the tuning range of the cavity. The measured results of the realized cavity match up to 90% with the RF simulation results. The overall volume and mass of the realized cavity are about 86 cm3 and 120 g, respectively, making it suitable for portable space based applications.

A Comprehensive Overview of Atomic Clocks and their Applications

“…As seen in Table 1, Rb atomic clocks are the most common and widely used clocks in GNSS, hence indigenous Rb clock has been developed independently at ISRO. [53][54][55][56] Due to their reliable operation in GNSS, with importance to Rb standards, we will cover its operation in brief in the next section. A typical space qualified Rb clock used in GNSS consists of an Electronic Power Conditioner (EPC) from which the power distribution to the clock package is given; base plate for temperature regulation of the clock; Rb atoms confined inside the physics package; local oscillator (quartz) and related control electronics.…”