Fourier analysis of strain measurement using highly birefringent two-mode optical fibers

A new approach to strain measurement based on Fourier analysis of strain-induced polarization and intermodal coupling in HB two-mode elliptical-core fibers is presented. We have applied the Fourier method to analyze different types of polarization and intermodal couplings occurring in a highly birefringent elliptical-core fiber (UMCS, Lublin). The results obtained indicate that Fourier spectra of sin-like strain-dependent characteristics can create a very important tool in projecting practical devices which will measure longitudinal strain in specific applications.