Silicon opto-electronic wavelength tracker based on an asymmetric 2x3 Mach-Zehnder Interferometer

Abstract

[EN] In this paper we report on the experimental demonstration of a Silicon-on-Insulator opto-electronic wavelength tracker for the optical telecommunication C-band. The device consist of a 2x3 Mach-Zehnder Interferometer (MZI) with 10 pm resolution and photo-detectors integrated on the same chip. The MZI is built interconnecting two Multimode Interference (MMI) couplers with two waveguides whose length difference is 56 mm. The first MMI has a coupling ratio of 95:05 to compensate for the propagation loss difference corresponding to the 56 mm. The wavelength tracker design provides three complementary, with 120◦ phase relations, responses. The MZI optical responses exhibit rejection as good as 15 dB, thanks to asymmetric design for the input coupler. Synchronized recorded DC electronic responses for the three photo-detector outputs reproduce the MZI de-phased characteristic, allowing for monitoring wavelength changes with sign.