A Non-Mechanical Multi-Wavelength Integrated Photonic Beam Steering System

• Published in: Journal of lightwave technology 2021-06, Vol.39 (12), p.4201-4208
• Main Authors: Alshamrani, Naif, Grieco, Andrew, Friedman, Alex, Johnson, Karl A., Kim, Myun-Sik, Floris, Francesco, O'brien, Peter, Fainman, Yeshaiahu
• Format: Article
• Language: English
• Subjects: Apertures; Arrayed waveguide gratings; Arrays; Beam steering; CMOS; Diameters; Infrared radiation; Lenses; Lidar; Microlenses; Optical ring resonators; Optical sensors; Optical switches; Optical tuning; Photonic integrated circuit; Photonics; Resonators; Switching; Tungsten base alloys; Waveguides
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2020.3034580

In this work we experimentally demonstrate a fully packaged one-dimensional beam steering system that is based on a fully CMOS compatible silicon photonics platform. This configuration enables multi-wavelength operation and is suitable for short-wavelength infrared (SWIR) applications from light detection and ranging (LIDAR) to telecommunication and sensing applications. The switching fabric in this system employs a 1x9 array of add/drop ring resonators that are fed by a common waveguide through a single etch input grating. The switching fabric re-directs the resonance wavelengths at each drop waveguide to the output facet at the edge of the chip and into free space. The divergent beams that exit the waveguides along the output facet are then collimated and magnified using an array of micro-lenses (pitch = 750 μm, Diameter = 700 μm) in addition to a two lens afocal system in order to enhance the fill factor and diminish any blind zones between adjacent beams. Each one of these drop waveguides is used to address portion of the steering aperture. Combined together they enable steering across the entire aperture. Multi-wavelength operation is obtained by placing individual titanium tungsten alloy (TiW) heaters on top of each ring resonator to enable wavelength tuning.