Method for stabilization of the maximum sensitivity of a two-arm interferometer using a multimode waveguide

The feasibility of stabilization of the maximum sensitivity of a two-arm Mach–Zehnder interferometer by varying the length of a multimode fiber waveguide in one of the arms (with the aid of a piezoelectric ceramic device) was confirmed experimentally. A quasiperiodic dependence of the interference signal on the waveguide length was obtained and it was found that the period of this dependence agreed well with the "cophasal" length of the waveguide. The interferometer was tuned to the optimal operation by bending a section of the waveguide to a specific radius.