The research activities carried out in the first two and a half years of UMWPCHIP have led to the following main advances beyond the state of the art:
• First multifunctional integrated hexagonal waveguide mesh in Silicon on Insulator technology capable of experimentally demonstrating over 30 different functionalities, including programmable Finite (FIR) and infinite impulse response (IIR) filtering, true time delaying, tunable beamforming by phase shifting and multiport interferometer emulation.
• First proposal and experimental demonstration of dual drive tunable directional couplers as elementary building blocks capable of the independent setting of amplitude and phase and their integration into the first-ever reported triangular waveguide mesh fabricated in Silicon Nitride.
• First-ever derivation and patenting of an analytic method to compute the scattering matrix of a two-dimensional photonic integrated device with full coupling in the X and Y axis. The fact that the method is analytic and not numerical allows a high-speed calculation time of the transfer function of multiport 2D devices, which is essential for further monitoring and control tasks.
• The proposal experimental demonstration and patenting of a new device, the Field Programmable Photonic Gate Array (FPPGA), which can be applied to MWP field but also in other areas such as quantum information processing, artificial intelligence and sensing.
• The first-ever development and experimental demonstration of multipurpose optimization techniques for the monitoring, control, and resource setting and programming of large-scale waveguide mesh circuits. The methods can rely either on prior measurement or calibration of the hardware elements or run without prior knowledge of the processor settings. These techniques combine the fast analytic scattering matrix method and refined population and machine learning optimization algorithms.
Complete end-to-end models for the design of FPPGA devices incorporating photonic, electronic and RF elements.
• Complete design and fabrication of a FPPGA featuring a silicon-on-insulator core with over 20 hexagonal cells and over 200 tuning elements, a complete electronics monitoring and driving unit, and Fiber optics and RF input/output ports.
During the six months extension of of UMWPCHIP, we completed the the following research results and progress beyond the state of the art:
• The demonstration of the above FPPGA device in several different MWP functionalities from the following list: filtering, beamforming, arbitrary waveform generation, 5G signal processing, switching, and true time delaying and performance operation complying with the RF metrics limited by state of the art integrated components.
• The demonstration of the same FPPGA device in other fields of applications, including the emulation of programmable multiport interferometers and the implementation of two or more simultaneous functionalities in the same hardware.
• The demonstration of the self-healing, autorouting and optimization capabilities of the FPPGA device.
