Replicated chirped waveguide gratings for optical sensing applications

A novel type of integrated optical sensor chip based on chirped grating couplers is presented. It can be used as a powerful basic building block for realizing miniature sensor modules for measuring and monitoring the values of a wide variety of chemical and physical quantities. The feasibility of fabricating these chips by means of very low-cost processes such as replication and thin film deposition is demonstrated. The most important theoretical fundamentals for calculating the performance of these chips are given. First experimental results, reported for replicated polycarbonate chips used in a flow cell to determine the refractive index of liquids, show their suitability for practical applications.