A compact, frequency stabilized laser head for space RB clocks and wavelength references

We present our ongoing development of a compact ( -14 at 10 4 s) laser-pumped Rubidium clock for space applications like, e.g., satellite navigation systems (GALILEO). A compact laser head was developed that includes frequency stabilization of the pump light to a reference cell. Recent clock stability results obtained with this laser head reach 2⋅10 -13 at 1000s, limited mainly by residual cell temperature coefficients and light shift effects. We discuss strategies to overcome these limitations and the relationship between the stabilities of the pump laser and the clock. Comparisons of the laser and clock frequency stabilities are presented for stabilization to both Doppler and sub-Doppler spectroscopy.