ABSTRACT
Inspired by the phased array concept that revolutionized RADAR technology through providing a compact, agile alternative to mechanical beam steering technology, optical phased arrays (OPA) have been an emerging technology enabling simple, affordable, and lightweight optical sensors offering precise, random-access, programmable multiple simultaneous laser beam steering, with a dynamic focus/defocus capability. As the importance of laser beam steering has long been recognized, over the past two decades various mechanisms have been developed including the opto-mechanical, electro-optical (EO) such as liquid crystal, and recently silicon photonics technologies. MEMS OPA requires the integration of thousands to millions of closely packed optical emitting facets and precise relative electronic phase control of these facets, all within a very small form factor. Compared with previous counterparts, MEMS OPA utilizes recent advances in photonic device density, circuit complexity, and performance capabilities in the emerging photonic integrated circuit (PIC) technology, and unprecedentedly enables high-speed random access laser beam steering with no moving parts or only microscale motions. Envisioned applications of OPA include, but are not limited to: surveillance, 3D imaging, precision targeting, and especially the recently emerging light detection and ranging (LIDAR) technology. This chapter gives an overview of the MEMS optical phased array technology, and then illustrates the theoretical background of optical phased arrays. The various designs and fabrication considerations of 1-D and 2-D MEMS OPA devices are also provided in the following sections.
