Raman laser with improved output power and lower sensitivity to the output coupler reflectivity

It is proposed to use a Raman laser with a new optical resonant cavity for the Roman radiation lambdaRR. Such resonant cavity is made out of an unpaired reflector rRR with a reflecting wavelength corresponding to said Raman radiation lambdaRR. The second reflector at the output needed to build an optical resonant cavity is advantageously defined by Rayleigh scattering to take place at least at a portion of the optical fiber between the reflector rRR and the output of that Raman laser. With the use of the Rayleigh scattering as a complementary reflector to be associated with the unpaired reflector, it is then possible to obtain an optical resonant cavity for the Raman radiation lambdaRR with an output reflectivity of less than 1% i.e. with optimized Raman radiation. Such Raman laser is particularly appropriated to be used as a second order Raman laser.