Design of an Exceptional-Surface-Enhanced Silicon-on-Insulator Optical Accelerometer

Non-Hermitian photonics has attracted increasing attention especially for sensing applications. Two coupled optical systems, designed to work at the "exceptional point", exhibit a strong spectral response to perturbations. Due to the enhanced sensitivity of exceptional points, they have been usually suggested as perfect candidates for high resolution sensing. The drawback of these configurations is their undesired sensitivity also to external fluctuations and noise that could eliminate the advantages of exceptional points. Recently, the concept of exceptional surface has been proposed to overcome this problem. In particular, coupling two counterpropagating modes in the same structure prevents differential noise in distinct cavities from affecting the exceptional-point condition. In this work we present a new configuration based on exceptional surfaces to design an optical accelerometer. The strong spectral response guaranteed by exceptional surfaces is used here to demonstrate the enhancement of the sensitivity of a Bragg grating-based optical accelerometer, reaching a value of 3 nm/g at 0.5 g.