An Ab Initio, Fully Coherent, Semi-Analytical Model of Surface-Roughness-Induced Scattering

Integrated optics and silicon photonics is a rapidly maturing technology progressing in telecom, computation, sensing. Surface-roughness-induced scattering the primary source of optical loss most photonic integrated circuits, as such, ultimately limits performance their applications. However, closed-form description for arbitrary refractive index profiles remains lacking, even though such one essential to enable an objective-oriented design waveguide platform. We present ab initio, fully coherent, analytical model based on volume current method that uses surface roughness' autocorrelation function unperturbed mode's electromagnetic fields predict coefficient closed form. An improved expression perturbation facilitates application also high-index-contrast systems. Hence, it flexible concerning wavelength, materials, fabrication process, geometry mode. Consequently, our may be seamlessly into simulation software suites, once roughness known utilized process. To verify model, we compare calculated losses measured propagation established models wide range systems literature. find previously neglected correlation along height significantly impacts scattering, which necessitates holistic statistical analysis roughness. believe these comprehensive prediction capabilities useful tool optimization fabrication, especially low-confinement applications like sensors.