Statistical properties of intensity of partially polarised semiconductor laser light backscattered by a single-mode optical fibre

We report the results of studying statistical properties of the intensity of partially polarised coherent light backscattered by a single mode optical fibre. An expression is derived for the deviation of the backscattered light intensity depending on the scattering region length, the degree of the light source coherence and the degree of scattered light polarisation. It is shown that the backscattered light in a fibre scattered-light interferometer is partially polarised with the polarisation degree $P=1/3$ in the case of external perturbations of the interferometer fibre.