Theoretical and experimental analysis of the complex dynamics of spectral RMS width of an erbium-doped figure eight fiber laser

There are a large number of different ultrashort light pulses; a particular case is called noise-like pulses (NLPs), which are ultrashort light pulses that have the characteristic that their electric field has a very complex internal structure. Due to this characteristic, the envelope can take various shapes (Gaussian, triangular, square, complex shape, etc.). Also its amplitude and temporal width vary with respect to the polarization within the cavity. In this work we carry out a theoretical and experimental study of the RMS widths of NLPs measured within the mode-locked regions generated with our laser cavity: an erbium-doped figure eight fiber laser (EDFEFL). The experimental measurements of the RMS widths of the NLPs were compared with the theoretical model of light intensity transmission based on Jones matrices and with the theoretical model of the NOLM. We find that the theoretical model partially fits with the experimental results. We analyze NLPs with a wavelength carrier of 960 nm, repetition rate of 60 MHz, and temporal profile with duration on the order of nanoseconds.