Similarity of adjacent-frame chaos waveforms from semiconductor fiber ring laser in sensing applications

摘要

Similarity of adjacent-frame chaos waveforms from a semiconductor fiber ring laser (SFRL) is investigated numerically in sensing applications. An improved model of a chaos optical fiber fence system based on a SFRL is presented. The optical fiber's SPM/XPM effects are considered. By this model adjacent-frame similarity's determinants are studied by comparing their cross-correlation function peaks at different parameters. The relationships between the similarity and the optical fiber's distributed linear birefringence effect, as well as SPM/XPM effects induced by the nonlinear birefringence are revealed by setting only one effect to work respectively. The characteristics of the chaos waveform with high similarity are researched by the autocorrelation function and power spectrum. The simulation results show that the similarity is more sensitive to the change of azimuth angle than that of the retardation angle of the polarization controller in the ring laser. It has almost no change with the ring length and injection current of semiconductor optical amplifier (SOA). The optical fiber's distributed linear birefringence and SPM/XPM effects mainly contribute to the formation of polarization chaos light however slightly decrease the similarity. The influence of nonlinear birefringence becomes big and decreases obviously the similarity only at an overlarge SOA current. The chaos waveforms with high similarity have big autocorrelation sub-peaks and the sub-peaks decrease slowly and gradually. Their power spectrums are mixed up with some periodic components. These results are helpful to choose the SFRL's parameters for the accurate disturbance location in a chaos optical fiber fence system.