Mach–Zehnder fiber interferometer for determination of the chromatic dispersion in single-mode fiber waveguides

A Mach–Zehnder fiber interferometer was based on two X-shaped directional couplers. These couplers and the reference arm of the interferometer were made of a fiber with a known dispersion characteristic. The spectral dependence of the group delay in the investigated waveguide was determined with a reproducibility of 0.01 ns/km. A good agreement was obtained between measurements of the dispersion with the aid of the fiber interferometer and those carried out using a Mach–Zehnder interferometer with an air reference arm.