Artificial neural networks are employed to predict the band structure of the one-dimensional photonic crystal nanobeam, and to inverse-design the geometry structure with on-demand band edges. The data sets generated by 3D finite-difference time-domain based on elliptical-shaped hole nanobeams are used to train the networks and evaluate the networks’ accuracy. Based on the well-trained forward prediction and inverse-design network, an ultrabroad bandgap elliptical hole dielectric mode nanobeam cavity is designed. The bandgap achieves 77.7 THz for the center segment of the structure, and the whole designing process takes only 0.73 s. The approach can also be expanded to fast-design elliptical hole air mode nanobeam cavities. The present work is of significance for further research on the application of artificial neural networks in photonic crystal cavities and other optical devices design.

We propose a sensor with high anti-interference ability using a photonic crystal cavity coupled system for simultaneous sensing of the refractive index (RI) and temperature (T) based on an electromagnetically induced transparency-like effect. A transparent window is achieved in the transmission spectrum through destructive interference between the air mode resonance and dielectric mode resonance in two one-dimensional photonic crystal structures. The T-sensitive material (SU-8) is used in the coupled system, promoting sensitivity and anti-interference ability. The ability of the system to simultaneously detect a small range of RI and T is demonstrated using three-dimensional finite-difference time-domain simulations and the fitting process. The RI sensitivities for the air and dielectric modes were 215 nm/refractive index unit (RIU) and 0 nm/RIU, respectively. The T sensitivities for the air and dielectric modes were 19 pm/K and − 83 p m / K , respectively. The sensor resists external interference, enabling it to resist the error caused by readings. The footprint of the sensor is 29 × 1.8 µ m 2 ( l e n g t h × w i d t h ), contributing to future optical on-chip integration sensor design.

We theoretically demonstrated breaking the quality factor-sensitivity (Q-S) limitation between the fundamental and higher order modes on a multimode silicon photonic crystal nanobeam cavity. Ultra-strong side-surface localizations benefited high-Q and high-overlap-integration resonances were achieved, simultaneously.

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Here we demonstrate the electromagnetically induced transparency and Autler–Townes splitting in a photonic-crystal-nanobeam-cavity-waveguide coupled system for the first time. This work enables to evaluate the interference of fields in integrated optical system.