Statistical properties and optical spectra of Raman fiber lasers: Influence of Bragg-grating mirrors

This paper present theoretical studies on how third order dispersion influences the optical spectrum of Raman fibre lasers (RFLs). Third-order dispersion effects arise from reflections at the fiber Bragg gratings (FBGs) mirrors used to close the laser cavity. The RFL studied here operates in a very common configuration so that the phenomenon presented here will arise in most of RFLs. Results obtained show that FLs may have connection with a phenomenon of anomalous thermalization recently described in nonlinear wave systems. Numerical investigations concerning the probability density functions (PDF) of the intracavity field are also presented. A model shows that reflection on the FBGs strongly influences the PDFs.