Statistics of backscattering in single-mode fiber

Rayleigh backscattering in single-mode fibers is helpful in loss measurements by OTDR and OFDR but troublesome when causing feedback to a semiconductor laser or when interfering with the signal in interferometric sensors. We show that the backscattered fraction of power Q = Iscatt/Iinput may fluctuate strongly for even minute variations of optical frequency ω or ambient temperature T, pressure p, or strain ε, possibly imposing severe limitations on applications.