Loop SBS oscillator on a stationary nonlinear refractive index grating

A loop SBS oscillator is studied, in which pump radiation coupled out from a nonlinear medium is directed backward to the medium. To increase the interaction length, a light guide is used. The feedback is obtained on a stationary nonlinear refractive index grating produced by the pump waves. The signal generated at the Stokes frequency in the loop propagates in the direction opposite to the pump and is amplified due to the classical backward SBS. Such an oscillator can be treated as a distributed feedback oscillator produced by the pump waves themselves.