Non-reciprocal response in silicon photonic resonators integrated with 2D CuCrP₂S₆ at short-wave infrared

Achieving non-reciprocal optical behavior in integrated photonics with high efficiency has long been a challenge. Here, we demonstrate a non-reciprocal magneto-optic response by integrating multilayer 2D CuCrP₂S₆ (CCPS) onto silicon microring resonators (MRRs). Under an applied magnetic field, the CCPS intralayer ferromagnetic ordering, characterized by easy-plane magneto-crystalline anisotropy, induces asymmetrical modal responses in the clockwise (CW) and counterclockwise (CCW) light propagation directions. The proposed configuration achieves a low insertion loss ranging from 0.15 dB to 1.8 dB and a high isolation ratio of 28 dB at 1550 nm. Notably, it exhibits a significant resonance wavelength splitting of 0.4 nm between the counter propagation directions, supporting a 50 GHz optical bandwidth. Operating directly in the transverse electric (TE) mode, it aligns with the main polarization used in silicon photonics circuits, eliminating the need for additional polarization management. The device is ultra-compact, with a 2D flake interaction length ranging from 22 µm to 55 µm and a thickness between 39 nm and 62 nm. Its operation range covers the entire C-band with a bandwidth of up to 100 nm. These attributes make our hybrid CCPS/Si device ideal for advanced non-reciprocal optical applications in the short-wave infrared (SWIR) spectrum, crucial for enhancing the resilience of optical systems against back-reflections.