Improved interferometric method for determination of refractive index profile parameters in single-mode waveguides

The simple nondestructive method suitable for the examination of single-mode graded-index waveguides is presented. Deposition of liquid immersion onto the waveguide surface and interferometric registration of induced mode index variations are used in this technique. The interferometer scheme is formed automatically in the usual procedure of waveguide mode launching. The use of additional side interference patterns allows avoiding spurious fringe sets in measurements.