Dependence of the threshold and spectral characteristics of a Raman laser on the spatially periodic pumping period

The dependence of the threshold and spectral characteristics of a distributed-feedback Raman laser on the modulation period is investigated theoretically and experimentally. It is shown that the effect of the distributed feedback of Stokes waves generated during spatial periodic pumping on the threshold and spectral characteristics is largely determined by the relative position of the distributed-feedback structure and the resonator mirror. Under experimental conditions, the decrease in the threshold pumping intensity due to distributed feedback was in excess of 30%.