Monolithically Integrated Optical Phased Array for Optical Wireless Communication

This paper presents a compact and power efficient one-chip optical phased array (OPA) transmitter (TX) for optical wireless communication (OWC). A traveling-wave-electrode Mach-Zehnder modulator (TWE-MZM) and mm-Wave driver, which would traditionally be implemented by bulky off-the-shelf components, are monolithically integrated with a silicon-based 1 x 64 OPA onto a single chip, reducing an active area of the entire system down to 6.4 mm(2). Moreover, a co-design and integration of TWE-MZM and mm-Wave driver largely minimizes the parasitics and mismatches of an interface between the TWE and mm-Wave driver. The 64-element optical antenna achieves beam divergence of 0.77 degrees and 4.23 degrees over transversal and longitudinal direction, respectively. The two-sided beam-steering angles of the array antenna in transversal and longitudinal direction are +/- 14.3 degrees and 6.1 degrees, respectively, while the side-lobe suppression ratio is 7.81 dB. The co-integrated TWE-MZM and driver support a measured data rate up to 15 Gbps and consume 210 mW. To the best of our knowledge, our proposed electronic-photonic integrated circuit is the first OWC-application OPA TX, which monolithically integrates TWE-MZM, CMOS driver, and OPA all in one-chip.