It is well known that the transmission of an optical signal through the turbulent atmosphere results in random phase fluctuations. In turn, these random phase fluctuations impart a random frequency fluctuation onto the optical signal. As laser radar (lidar) systems rely on the evaluation of micro-Doppler frequency shifts of the reflected optical wave to determine certain target characteristics, it is critical to understand the impact of the atmospheric induced frequency fluctuations. Additionally, lidar systems used for defense applications would typically operate in moderate to strong atmospheric turbulence conditions. Hence, for such applications, it is necessary to develop models describing atmospheric induced frequency fluctuations of an optical wave that are valid in all regimes of optical turbulence. In this paper, we present preliminary results for a model of atmospheric induced frequency fluctuations for the double pass propagation problem in weak optical turbulence conditions and a possible method for extension of these results into moderate to strong turbulence conditions.