Integrated nonlinearity calibration optical-electrical engine for FMCW LiDAR application

We demonstrate an integrated optical-electrical calibration module for improving the nonlinearity of the optical source for frequency-modulated continuous-wave (FMCW) LiDAR applications. The linearity of the light source has a con-siderable influence on FMCW LiDAR range performance, and calibration is typically necessary. However, a major-ity of existing calibration techniques are based on separate devices, resulting in high cost and limited integration. Our module is made up of a silicon photonic chip with a long optical delay line, a tunable phase shifter, two balanced pho-todetectors, and some passive components. For this module, we also built the aided amplification and voltage bias circuits. After packaging this module, we used it with our nonlin-earity calibration algorithm to analyze the laser's relative nonlinearity. After nonlinearity calibration, the laser rela-tive nonlinearity 1-r2 could be improved to 10-6 similar to 10-7. In the future, the calibration result of nonlinearity could be enhanced further by increasing the length of the on-chip optical delay line. (c) 2023 Optica Publishing Group