摘要： Photonic integrated circuits (PIC) have recently attracted extensive attention in advanced photonic signal processing to meet the ever-increasing demands on high-speed and ultra-compact data signal management. However, programmable and multi-task photonic signal processing is still full of challenges, especially the scalable photonic integration solution. Here, we design, fabricate and demonstrate a mesh-structure-enabled programmable multi-task photonic signal processor on a silicon chip. It relies on a scalable 2D mesh structure network with a number of hexagonal unit cells formed by building blocks of tunable Mach-Zehnder interferometers (MZIs). We study several simple and complex optical filtering functions using configured single ring resonator, cascaded ring resonators, ring assisted MZI, cascaded MZIs, reconfigurable and tunable comb filter and (de)interleaver, and dual-injection ring resonators. For the proof-of-concept demonstration of on-chip programmable multi-task photonic signal processing, a monolithically integrated silicon chip with four hexagonal unit cells is fabricated with greatly reduced geometric dimension. By appropriately adjusting the thermo-optic phase shifters of MZIs, versatile programmable multi-task photonic signal processing functions are demonstrated in the experiment with impressive performance, including single ring resonator, cascaded ring resonators, asymmetric MZI, ring assisted MZI, optical delay line, multi-port router, N×N optical switch, and optical neural network (ONN) enabled self-configurable router and switch and their practical applications in fiber-optic communication systems. The demonstrations may open up new perspectives for on-chip solutions to ultra-compact, reconfigurable, programmable and multi-functional data signal management in advanced optical communication networks.