Calibration-Free On-Chip Spectrometer Based on Topological Waveguides

The demand for miniaturized on-chip spectrometers is growing rapidly in the field of portable optical sensing. However, fabrication-induced defects commonly encountered in current on-chip spectrometers alter the response of the devices, thereby degrading the accuracy of spectral reconstruction. To circumvent the need for complex defect-correction calibrations, we demonstrate a calibration-free on-chip spectrometer using topological photonic waveguides. The spectrometer’s inherent topological protection feature withstands manufacturing and defect-induced fluctuations, enabling high accuracy spectral reconstruction despite the presence of manufacturing and defect errors. When defect errors are present, the relative error (ε) of spectral reconstruction does not exceed 0.029 across a 176 nm bandwidth. Additionally, with the introduction of random errors up to 5 and 10 nm, the ε remains below 0.04 and 0.059, respectively. This design leverages the topological photonic structure’s tolerance to defects, ensuring stable performance for robust portable spectrometers.