Low cost, power efficient, scalable beam steering for photonic circuits

Engineers in Prof. Amir Safavi-Naeini's laboratory have developed an inexpensive, on-chip optomechanical system that harnesses sound waves to form and direct a beam in free-space, achieving high resolution, millimeter-scale apertures with low mechanical drive power (hundreds of microwatts per antenna). Conventional two-dimensional mechanical beam deflection systems are large, heavy, slow and expensive, while the current alternative on-chip optical phased arrays (OPAs) cannot steer monochromatic light. This new, compact on-chip optomechanical antenna (OMA) employs acoustic waves (sound) as a naturally tunable grating to scatter light, thereby independently forming and steering beams of different colors with ultra-low cost and power requirements. These rapidly reconfigurable OMAs can be fabricated with standard microelectronics processes on a silicon-on-insulator chip and can be readily incorporated into current silicon photonics components as well as integrated electronics. This agile, scalable beam steering system could enable a host of imaging, display, communication, targeting, guidance and navigation technologies.

Optomechanical antenna arrays.a, A mechanical wave scatters a guided optical wave to steer a beam through a range of angles b, micron-scale antennas with guided optical and guided mechanical modes form a beam in the far-field directed into a designated angle. c, antennas are incorporated into a phased-array driven by a single piezoelectric transducer.

Stage of Research
The inventors have designed the silicon photonic system with photonic waveguides that achieves 44? field of view with 880 resolvable spots by sweeping the mechanical wavelength with about a milliwatt of mechanical power. The beam direction, beam shape and the number of beams can be quickly reconfigured using mechanical waves as nonreciprocal, active gratings.