Compact and frequency stabilized laser heads for Rubidium atomic clocks

Abstract

Abstract-We present the development and complete spectral characterization of our compact and frequency-stabilized laser heads, to be used for rubidium atomic clocks and basic spectroscopy. The light source is a Distributed Feed-Back (DFB) laser diode emitting at 780 nm or 795 nm. The laser frequency is stabilized on a sub-Doppler absorption peak of the 87 Rb atom, obtained from an evacuated rubidium cell. These laser heads, including the electronics for the light signals detection, have an overall volume of 0.63 liters. We also present a variant of the laser head into which is integrated an Acousto-Optical Modulator (AOM) that precisely detunes the laser frequency in order to minimize the AC Stark shift in Rb atomic clocks.

Compact rubidium-stabilized multi-frequency reference source in the 155-μm region

“…The 780-nm light is directed into an in-house frequency reference unit (FRU) with extremely similar features as previously reported [10]. The laser light probes Rb atoms in a sub-Doppler saturated absorption scheme at 780 nm (D2 line) with a single retroreflected beam.…”

“…These easily achievable sub-Doppler lines make the Rb D2 transition at 780 nm particularly favorable as a frequency reference in the 1.56-μm optical telecommunication region through second-harmonic generation (SHG) [8,9], and for lasers probing CO 2 lines at 1.57 μm. Rb-based frequencystabilized laser heads were developed, demonstrating fractional frequency stability better than 1 · 10 −11 and 2 · 10 −12 at all timescales between 1 s and 1 day for a distributed feedback (DFB) laser [10] and an extended-cavity diode laser [11], respectively. Two-photon transition of rubidium atoms is also used for frequency standards at 1556 nm, demonstrating high stability at the level of 10 −13 or better between 10 and 1000 s [12], however in a less simple and compact setup.…”

Compact and high-performance Rb clock based on pulsed optical pumping for industrial application

“…The laser head is similar to the laser systems developed previously, where the AOM served only for shifting the laser frequency [13]. In the newly-developed laser head used here, the AOM is implemented to realize both the laser output switching and frequency shifting.…”

Methods and setup for spectral characterization of laser diodes for atomic clocks

“…The setup described in this communication has been initially designed in the frame of a European project aiming for the characterization of a large number of laser diodes emitting at 852 nm and 894 nm and is presently being upgraded in the frame of a project funded by the European Space Agency. Therefore, the setup description and optical components given here are in accordance with these wavelengths; they can easily be adjusted in case of characterization of 780 nm or 795 nm emitting laser diodes that could be used for Rb applications [7,8].…”