Method for measuring waveguide propagation losses by means of a Mach–Zehnder Interferometer structure

In this paper, a method for measuring waveguide propagation losses by means of a Mach–Zehnder Interferometer (MZI) structure is reported. The method, based on the analysis of the transmission spectra of asymmetric MZIs, enables the propagation losses of the optical waveguides to be calculated without the requirement of identical coupling conditions for each measurement. In addition, the power imbalance of the branching structure in the MZI can also be obtained. Our theoretical analysis is supported by experimental measurements.