Investigating the frequency-dependent amplification of a tapered amplifier in atom interferometers.

We present the investigation on the frequency-dependent amplification (FDA) of a tapered amplifier (TA) and the corresponding influence on Raman-type atom interferometers. In our interferometer, the output of two phase-locked diode lasers is injected into a TA to generate Raman beams. The frequency of one laser is chirped during the interfering process, which induces a variance of the Raman lasers power as a result of the FDA of the TA. The corresponding power ratio variation of the Raman lasers is measured by beat note method, which shows a linear dependence with a slope of -0.087(4)/GHz when the laser frequency changes over 2 GHz at 780 nm. The corresponding error related to AC Stark effect due to this frequency-dependent variation is estimated for our atom interferometer. The investigation presented here may provide hints for other experiments involving TAs.