Multichannel anisotropic single-mode fiber waveguide for fiber-optic sensors

Single-mode fiber waveguides with two and four identical weakly coupled channels in a shared quartz cladding were developed. Specific features of these waveguides were conservation of the mutual coherence of the radiation in the channels, identical orientation of the birefringence axes in diametrically opposite channels, and azimuthal dependence of the relative phase shift in the channels as a result of lateral deformations. These properties made it possible to construct simple systems for a number of fiber-optic sensors of strain, pressure, velocity, etc.