POLARIZATION DYNAMICS OF A FIBER FABRY-PEROT LASER WITH FEEDBACK

Experimental results on the low-frequency polarization dynamics of a f ree-running Nd-doped optical fibre laser and a fibre laser with deriva tive feedback are presented. It is found that the power spectrum of ea ch polarization mode reveals three relaxation peaks. Using the combine d (negative and positive) derivative feedback it is possible to suppre ss noise in the region of the in-phase relaxation oscillations and to excite noise in the region of one of the two antiphase relaxation osci llations. The model developed of a class B laser with two orthogonal e lliptically polarized modes is checked and explains the main experimen tal features of relaxation oscillation peaks.