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

Abstract

Combining light modulation and frequency conversion techniques, a compact and simple frequency-stabilized optical frequency comb spanning over 45 nm in the 1.56-μm wavelength region is demonstrated. It benefits from the high-frequency stability achievable from rubidium atomic transitions at 780 nm probed in a saturation absorption scheme, which is transferred to the 1.56-μm spectral region via a second-harmonic generation process. The optical frequency comb is generated by an electro-optic modulator enclosed in a Fabry-Perot cavity that is injected by the fundamental frequency stabilized laser. Frequency stability better than 2 kHz has been demonstrated on time scales between 1000 s and 2 days both at 1560 nm, twice the rubidium wavelength, and for a comb line at 1557 nm.

On the benefit of airborne demonstrators for space borne lidar missions

“…Airborne demonstrators help to overcome technological challenges, investigate sub-systems such as innovative frequency stabilisations schemes (e.g. [21]) in relevant environments, test algorithms under realistic conditions with real data, and provide important means to increase the technological readiness level on a sub-orbital platform. This has impressively been shown in the course of the development of the series of airborne lidars at DLR in the past years.…”

First investigation of an all-fiber versatile laser frequency reference at 2 µm for CO2 lidar applications

“…At 1572 nm, the targeted frequency stability (in terms of Allan deviation) of 20 kHz above 700-s integration time was demonstrated [3], reaching values of 2 kHz at 1 s and < 800 Hz from 1 hour up to 3 days. This was achieved using a configuration with an electro-optic modulator (EOM) frequency comb bridging the spectral gap between a 1572-nm slave laser and a 1560-nm master laser, frequency-doubled and locked to a Rb transition [4]. The achieved frequency stability of the master and slave lasers coincided with the stability of similar Rb-stabilized lasers at 780 nm, so that the good frequency stability of Rb locking was efficiently transferred to the 1.56-m spectral range.…”

A tunable low-drift laser stabilized to an atomic reference

“…However, a comb and a suitable reference are required for such an approach, both of which are resource intensive and therefore not generally available in all laboratories. For bridging frequency ranges of up to a few THz, an EOM inside a Fabry-Perot cavity can be used to produce a narrow band frequency comb [28]. As an alternative, a cavity can be used to transfer the stability of a reference laser to the spectroscopy laser [22,[29][30][31][32][33][34].…”