A disturbed optical interferometric sensor analyzed on complex s-plane: A new novel vectorial detection technique for the interference patterns

Abstract

In this work, the interference pattern produced by a disturbed optical interferometer in its optical cavity, is analyzed in the complex s-plane and the new detection technique is called vectorial detection on complex s-plane for the interference patterns (VDCSP_IP). The technique VDCSP_IP requires a complex reference vector s0ref, a complex measurement vector s0med and with their difference a complex detection vector is defined: s0det=s0ref-s0med. Considering the vector s0det four operating conditions are established: first, if s0det=0, then the optical interferometer is not detecting any physical variable; second, if s0det≠0 then the optical interferometer is detecting some physical variable; third, if θ=360o then s0det=0 since the perturbation provokes a complete cycle; fourth, the phase θ must be into the interval 0o<θ<360o. The VDCSP_IP technique was confirmed by simulating the interference pattern of a low-finesse Fabry-Perot interferometer based on two identical Bragg gratings. Based on the numerical results, the theoretical and numerical experiments are in agreement and the four operating conditions were corroborated.The technique VDCSP_IP finds potential application in the signal demodulation of interferometers and in the signal processing of quasi-distributed sensors based on interferometry.