The tritter-Mach-Zehnder

A schematic of the setup of the three-path Mach-Zehder interferometer is shown below. The main components are the two integrated fiber tritters (3×3-couplers manufactured by SIFAM, England).

The phases in the interferometer were changed using piezo tubes and the output intensities were recorded by a digital storage oscilloscope. The interferograms obtained from the raw data are compared with theoretical calculations in the following picture: