Integrated optical system for scalable and accurate inspection systems

Abstract

An inspection system includes a radiation source, an integrated optical system, and first and second detectors. The radiation source generates radiation to irradiate a target. The integrated optical system includes: a substrate; first, second, third, and fourth waveguides; first and second grating couplers; a first combiner coupled to the first and second waveguides; and a second combiner coupled to the third and fourth waveguides. The first grating coupler couples first and third portions of radiation scattered by the target respectively into the first and third waveguides. The second grating coupler couples second and fourth portions of radiation scattered by the target respectively into the second and fourth waveguides. The first combiner can combine the first and second portions of radiation. The second combiner can combine the third and fourth portions of radiation. The first and second detectors generate measurement signals based on the corresponding combined portions of radiation.