Multibeam Optical Phased Array and Monolithically Integrated Electro-Optic Modulator for High-Performance Wireless Communication

In this paper, we present a new transmitter that consists of multibeam generating optical phased array (OPA) and a monolithically integrated electro-optic (EO) modulator, achieving compact system area and high energy efficiency, for optical wireless communication (OWC). A concept of using both path length difference between the routing waveguides in the OPA and wavelength-division multiplexing is demonstrated to simultaneously create multiple beams in free-space and transmit data to receivers at different location, with a small device footprint. To further reduce the power consumption and area of the transmitter, the EO modulator and CMOS driver are co-designed and integrated in a single chip, using 45-nm monolithic silicon photonics technology. The EO modulator leverages an optical digital-to-analog converter structure, supporting both two-level and four-level pulsed amplitude modulations. The chip size of the 101-element OPA is 180 mm2, and an active area of the co integrated modulator and CMOS driver is 3.4 mm2. The combined OPA and modulator system achieves maximum data rate and power consumption per beam/channel of 54 Gbps and 7.11 pJ/bit, respectively.