Tuning transfer function of fiber-optic Fabry–Pérot interferometer via introduction of birefringence in the cavity

The study investigates the impact of birefringence exhibited by the cavity material of a fiber-optic Fabry–Pérot interferometer on its transfer function. The theoretical approach to analyze the effect of birefringence in the cavity of a plane Fabry–Pérot interferometer is described. The case of high- and low-finesse interferometer is investigated. It is shown that introduction of a birefringent medium of optimized parameters can be used to increase the density of interference fringes in certain wavelength range – the feature can be used either for reduction of the cavity length in an interferometric sensor or operation with sources of narrower spectral characteristics