Experimental investigation of the residual waves in a multiwavelength Brillouin-erbium fiber laser

In this work, an experimental investigation on the properties of residual waves in a multiwavelength Brillouin-erbium fiber laser (BEFL) is carried out. The investigation is further extended to the nonlinear phenomenon behavior of stimulated Brillouin scattering (SBS) and Rayleigh scattering in a 400 m single mode fiber (SMF). Findings of this work are unveiled by comparing the output power of the forward propagation (residual waves) with respect to the backward propagation BEFL for better understanding. It is found in this paper that the residual waves are the responsible components for the enhancements of the number of spectral lines in the BEFL.