Flexible Photonic Integrated Circuits: A New Paradigm to Process Data on-Board Satellites

Photonic Integrated Circuits (PICs) are an enabling technology for a large range of field applications, also including Space. In this context, New Space Economy sets several constraints mainly in terms of reliability and flexibility of on-board systems, taking into account the need for small size and low weight, low propagation losses, immunity to electromagnetic disturbances, high processing speed, wide bandwidth, and radiation resistance. Reconfigurable PICs are one of the most promising technologies to fulfil all those requirements. In particular, system flexibility could be achieved by means of programmable or tuneable application-specific PICs (ASPICs). A tuneable ASPIC should be tailored according to the targeted applications, also by reconfiguring itself in relation to the user demands or external environment, at the expense of recursive designing costs, and low flexibility. On the other hand, a programmable PIC performs several functions on a single chip, even if targeted to different applications, with a resulting larger flexibility although with high power consumption and worst performance with respect to ASPIC. Synthetic Aperture Radar (SAR) systems can benefit from these technologies to process onboard image data with a severe reduction of data transfer to the ground station. In this framework, an innovative reconfigurable Ka-band LiNbO3 ASPIC has been proposed, acting as an 8-bit Fourier Transform Spectrometer, to compress echo data and process directly on-board, with a significant improvement of the performance (e.g., footprint, processing time) with respect to the standard counterparts (MMIC, ASIC, FPGA).