A Silicon-Based Optical Signal Transmitter for Sub-THz Wireless Communication Systems

We present the compact integration of an optical heterodyne-based terahertz transmitter in silicon, including ring filters and a dual-parallel Mach Zehnder modulator. The transmitter module has a footprint area of 2.4x0.4 mm and is integrated into the open-access Tower’s PH18MA silicon photonics platform. Ring-based bandpass filters and single Mach Zehnder modulator, essentials building blocks of an optical heterodyne system, feature the following: high wavelength selectivity over a 100 GHz free spectral range and intensity modulation capabilities performing a data transmission test, respectively. This study reveals the potential of this state-of-the-art integration platform to enable complex transmitter modules based on silicon for high-speed operation, low phase noise thanks to the phase-locking scheme via ring filters and flexible multilevel modulation formats.