Asymmetric laser sideband generation with a tapered semiconductor amplifier

We have constructed a free-space, frequency-shifted feedback amplifier using a tapered semiconductor gain element. The general layout of the system is similar to that described in Littler, et al., \textit{Opt. Comm.} \textbf{88}, 523 (1992). Traveling-wave feedback is demonstrated with the $m=-1$ order of several different acousto-optic modulators driven at variable frequency. Asymmetric sideband production is observed in the rf spectrum of a fast photodiode and in the transmission of a scanning Fabry-Perot interferometer. The number of asymmetric modes is controlled with the AOM rf drive power and the seed laser optical power.