Rubidium atomic oscillator with laser diode wavelength adjustment

Abstract

A rubidium atomic oscillator includes a voltage-controlled oscillator (VCO) producing a first microwave signal for an output, and a light source producing pumping light of which the wavelength is externally controlled. The oscillator further includes a division part for dividing the pumping light into a first light and a second light, a wavelength shift part changing a wavelength of the second light to produce a third light, and a cavity resonator, oscillated by a second microwave signal, which absorbs the first light and the third light, the cavity resonator having a resonance cell filled with a rubidium gas. In an electrical control part, the second microwave signal is produced based on the first microwave signal from the VCO, a level of the first light passed through the cavity resonator is detected, and a frequency of the VCO is controlled so that the first light is maximally absorbed in the cavity resonator. In an optical control part, a level of the third light passed through the cavity resonator is detected and the wavelength of the light source is controlled so that the third light is maximally absorbed in the cavity resonator. In the oscillator, by properly changing a wavelength of the third light in the wavelength shift part, stability of the first microwave signal may be increased.