Ultra-Compact Large Extinction Ratio Fano Resonance From Photonic Crystal Nanobeam Cavity

An ultra-compact photonic crystal nanobeam cavity (PCNC) with a gradient period constant achieves a high extinction ratio (ER) of 46.108 dB in only 12.6 μm². Fano resonance is induced via continuum mode coupling by integrating a partial transmission element (PTE), yielding a single, sharp resonance peak across the 1500 – 1600 nm band. Experimental results confirm pronounced Fano transmission spectra and effective thermally induced wavelength shift. The device is designed for multi-project-wafer (MPW) compatibility, providing exceptional spectral control at sub-wavelength scales, meeting the low-power, high-density requirements of photonic computing and offering broad application potential in photonic convolutional neural networks (CNNs).