  The mid-term fractional frequency stability of miniaturized atomic clocks can
be limited by light-shift effects. In this Letter, we demonstrate the
implementation of a symmetric Auto-Balanced Ramsey (SABR) interrogation
sequence in a microcell-based atomic clock based on coherent population
trapping (CPT). Using this advanced protocol, the sensitivity of the clock
frequency to laser power, microwave power and laser frequency variations is
reduced, at least by one order of magnitude, in comparison with continuous-wave
(CW) or Ramsey interrogation schemes. Light-shift mitigation obtained with the
SABR sequence benefits greatly to the clock Allan deviation for integration
times between 10$^2$ and 10$^5$ s. These results demonstrate that such
interrogation techniques are of interest to enhance timekeeping performances of
chip-scale atomic clocks.
