Measuring the difference in group delays between the cores of a multicore optical fiber by means of time-domain interferometry

A way of measuring the difference in group delays between the cores of multi-core optical fiber is proposed. The method is based on a low-coherence Mach–Zehnder interferometer and a broadband radiation source. The corresponding experimental setup is constructed and a seven-core optical fiber with identical cores manufactured at the Fiber Optics Research Center, Russian Academy of Sciences, is studied.