Mach–Zehnder Interferometers Composed of µ-Bends and µ-Branches in a Si Photonic Wire Waveguide

We fabricated compact Mach–Zehnder interferometers consisting of µ-branches and/or µ-couplers in a Si photonic wire waveguide. Clear interference spectra with a maximum extinction ratio of more than 20 dB and an alternating light output between two output ports were observed. A high diffraction order of 300 was also demonstrated within a small foot space of 30×20 µm 2 .