Stress optic modulator using thin-film PZT for LIDAR applications

This paper presents the development of a stress optic modulator which can be implemented in an optical sensor system such as LIDAR. In LIDAR, an Optical Phased Array (OPA), consisting of several optical waveguides, can be used to steer the direction of light beams. The beam steering can be achieved using phase shifters where the delay for different optical waveguides is changed via the waveguide optical index by applying a mechanical stress using thin-film piezoelectric actuators. Finite Element Method (FEM) simulation was used to design the stress optic modulator and demonstrators were built on 200 mm silicon wafers and thin-film Pb(Zr0.52,Ti0.48)O3 (PZT) material. Electrical and optical measurements were performed on our stress optic modulator and show the efficiency of the PZT phase shifter as being in the range of VπLπ = 20-26 V.cm, with an estimated energy dissipation of 800 nW per π phase shift. The proposed method suggests an alternative path to low power and high frequency solid-state LIDAR optical sensor systems.