The distributed fiber sensing system based on a polarization chaos ring laser(PCRL),which is sensitive to initial conductions,is presented.Its detectable characteristics are studied theoretically and experimentally.Numerical investigation and preliminary experimental results show that the PCRL can be used to detect a stress or vibration acting on the sensing fiber and changing its retardation angle by the change of the temporal output waveforms.Besides,in order to enhance the detecting sensetivity,a more ef...