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arXiv · 2008.10369

Verniered Optical Phased Arrays for Grating Lobe Suppression and Extended FOV

Nathan Dostart·Bohan Zhang·Michael Brand·Daniel Feldkhun·Miloš Popović·Kelvin Wagner
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Abstract

Optical phased arrays (OPAs) which beam-steer in 2D have so far been unable to pack emitting elements at $\lambda/2$ spacing, leading to grating lobes which limit the field-of-view, introduce signal ambiguity, and reduce optical efficiency. Vernier schemes, which use paired transmitter and receiver phased arrays with different periodicity, deliberately misalign the transmission and receive patterns so that only a single pairing of transmit/receive lobes permit a signal to be detected. A pair of OPAs designed to exploit this effect thereby effectively suppress the effects of grating lobes and recover the system's field-of-view, avoid potential ambiguities, and reduce excess noise. Here we analytically evaluate Vernier schemes with arbitrary phase control to find optimal configurations, as well as elucidate the manner in which a Vernier scheme can recover the full field-of-view. We present the first experimental implementation of a Vernier scheme and demonstrate grating lobe suppression using a pair of 2D wavelength-steered OPAs. These results present a route forward for addressing the pervasive issue of grating lobes, significantly alleviating the need for dense emitter pitches.

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Nathan Dostart, Bohan Zhang, Michael Brand, Daniel Feldkhun, Miloš Popović, Kelvin Wagner. 2020-07-22. Verniered Optical Phased Arrays for Grating Lobe Suppression and Extended FOV. https://arxiv.org/abs/2008.10369

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