Polarization noise from forced vibration in a birefringent single-mode fiber link

Stable optical output from birefringent or polarization-preserving fibers is required in coherent optical communication and fiber-optic sensor systems. Fluctuations in the state of polarization (SOP) in birefringent fibers resulting from environmental conditions such as thermal drift and mechanical movement can induce intensity noise if polarization-dependent elements are included in the fiber link.1,3 The polarization noise originating from angular misalignment of the axes in the coupling of two birefringent fibers and/or the axes of the input fiber also has been discussed and analyzed.4