Abstract: A cascaded Raman laser (10) has a pump radiation source (12) emitting at a pump wavelength &lgr;p, an input section (14) and an output section (16) made of an optical medium. Each section (14, 16) comprises wavelength selectors (141, 142, . . . , 145 and 161, 162, . . . , 165) for wavelengths &lgr;1, &lgr;2, . . . , &lgr;n−k, where n≧3, &lgr;p<&lgr;1<&lgr;2< . . . <&lgr;n−1<&lgr;n and &lgr;n−k+1, &lgr;n−k+2, . . . , &lgr;n being k≧1 emitting wavelengths of the laser (10). The laser further comprises an intracavity section (18) that is made of a non-linear optical medium, has a zero-dispersion wavelength &lgr;0 and is disposed between the input (14) and the output (16) section. The wavelengths &lgr;1, &lgr;2, . . . , &lgr;n−k of the wavelength selectors (141, 142, . . . , 145 and 161, 162, . . .