Fabrication of a micromachined optical modulator using the CMOS process

This paper presents a new micromachined optical modulator design with electrostatic actuation fabricated by the conventional complementary metal-oxide semiconductor (CMOS) process. The modulator is operated by the interaction of the fixed part, stationary gratings and the movable part, sliding gratings. The period of the gratings varies with the slide of the movable part, thereby allowing different diffraction patterns of the reflected light. In addition, 100% modulation in the first order can serve as an optical switch. All procedures following the CMOS process merely require a simple post-process with maskless etching. With different profiles of the shape and sacrificial layer, two types of modulator are developed to obtain a high-aspect ratio and high efficiency of modulation, respectively.