Silicon photonic MEMS multi-beam laser scanner with integrated angle sensors

<jats:p>Silicon photonic laser beam scanning offers a promising route to integrated microsystems for light detection and ranging (LiDAR), free-space optical communications, near-eye microdisplays, and confocal microscopy. MEMS beam scanners with integrated photonic waveguide emitters can substantially reduce the number of control signals required relative to optical phased arrays. However, important challenges remain, including the tradeoff between scan speed and angular resolution, limited mechanical deflection angles, beam-angle sensing, and scaling of emission apertures for low-divergence beams. Here, we present a silicon photonic MEMS two-dimensional beam scanner, co-packaged with a piezoelectric actuator, that scans multiple addressable beams from a silicon nitride grating emitter and integrates silicon piezoresistive strain sensors---both supported by a robust silicon backbone. This multi-beam architecture mitigates the scan speed–resolution tradeoff and enables a larger field of view for a given mechanical deflection range, while the strain sensors provide beam-angle readout and the silicon backbone supports relatively large emission apertures. Our foundry-fabricated prototype emits four independently addressable beams over 594-1050 nm, each scanning a parallelogram-shaped angular region of up to approximately 9.5° x 7.8°. Together, the four beams provide an estimated maximum of 1280 resolvable spots. At λ=1050 nm, overlap among the scanned regions produces two extended, continuous fields of view measuring 18.2° x 5.7°. Pathways toward increasing the number of resolvable spots and addressable beams are discussed.</jats:p>