Non-Hermitian skin effect in a coupled microring resonator array

Non-Hermitian photonics has emerged as a powerful paradigm for exploring novel topological phenomena and achieving advanced optical manipulation in integrated photonic systems. here, we explore the non-Hermitian skin effect (NHSE) in a one-dimensional coupled micro-ring resonator array fabricated on a silicon photonic chip. By introducing asymmetric couplings through engineered loss, we demonstrate how the NHSE leads to frequency-dependent light localization at the boundaries of the system. Both simulations and experimental measurements confirm the emergence of this localization, particularly highlighting a bipolar NHSE where the direction of mode accumulation is determined by the optical frequency. Our design is based on a tight-binding model and implemented in a passive, CMOS-compatible platform. The study not only provides a practical approach to realize and observe NHSE in integrated photonic circuits but also offers potential applications in topological light manipulation, on-chip sensing, and non-reciprocal photonic devices. This chip-scale demonstration opens up new opportunities for utilizing non-Hermitian physics in scalable optical systems.