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Optical phased arrays (OPAs) which beam-steer in two dimensions (2D) are currently limited to grating row spacings well above a half wavelength. This gives rise to grating lobes along one axis which limit the field of view (FOV), introduce return signal ambiguity, and reduce the optical efficiency in lidar applications. We demonstrate a Vernier transceiver scheme which uses paired transmit and receive phased arrays with different row periodicities, leading to mismatched grating lobe angular spacings and only a single aligned pair of transmit and receive lobes. This permits a return signal from a target in the desired lobe to be efficiently coupled back into the receive OPA while back-scatter from the other grating lobes is rejected, removing the ambiguity. Our proposal goes beyond previously considered Vernier schemes in other domains like RF and sound, to enable adynamic Vernierwhere all beam directions are simultaneously Vernier aligned, and allow ultra-fast scanning, or multi-beam, operation with Vernier lobe suppression. We analyze two variants of grating lobe suppressing beam-steering configurations, one of which eliminates the FOV limitation, and find the conditions for optimal lobe suppression. We present the first, to the best of our knowledge, experimental demonstration of an OPA Vernier transceiver, including grating lobe suppression of 6.4 dB and beam steering across 5.5°. The demonstration is based on a pair of 2D-wavelength-steered serpentine OPAs. These results address the pervasive issue of grating lobes in integrated photonic lidar schemes, opening the way to larger FOVs and reduced complexity 2D beam-steering designs.
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Grating Coupled Attachment of Optical Fiber Arrays for in situ Photonics Experimentation
We report a simple, vacuum-compatible fiber attach process forin situstudy of grating-coupled photonic devices. The robustness of this technique is demonstrated on grating-coupled waveguides exposed to multiple X-ray irradiations for aerospace studies.
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- Award ID(s):
- 2052742
- PAR ID:
- 10598837
- Publisher / Repository:
- Optica Publishing Group
- Date Published:
- ISBN:
- 978-1-957171-39-5
- Page Range / eLocation ID:
- ATh1J.3
- Format(s):
- Medium: X
- Location:
- Charlotte, North Carolina
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1364/CLEO_AT.2024.ATh1J.3
