A simple analytic model of a cw multicascade fibre Raman laser

A simple model of a multicascade fibre Raman laser is considered and analytic expressions are obtained for its output characteristics. The efficiency of the Raman laser is shown to be determined to a considerable extent by the lumped optical loss of the cavity. A proposal is made to estimate the quality of optical fibres as an active medium for multicascade fibre Raman lasers from the efficiency of the model Raman laser.