Improved model and dynamic mechanism of a semiconductor fiber ring laser for distributed sensing

The dynamic model of semiconductor fiber ring laser (SFRL) is improved by employing the distributed birefringence model of the fiber. A matrix is introduced to the laser model which is made up of a stochastic sequence with Rayleigh distribution. The framing structure characteristic of chaos waveform and the similarity of adjacent frames are observed with this improved model. It is the fiber birefringence that contributes to the framing structure of output chaos waveforms and the adjacent-frame similarity. The disturbance changed the birefringence Rayleigh distributed and then changed the Jones matrix of the fiber ring. Namely, the initial state of the chaotic system is changed. Duo to the sensitivity of a chaotic system to its initial conditions, the change brings variety in the output waveform. Therefore the adjacent-frame similarity decreases when a disturbance acts on the fiber. The disturbance in different position leads to different decrement in the degree of similarity of adjacent frames. So the validity of the cross-correlation method for detecting and locating a disturbance is confirmed by the simulation again.