Achieving full grating-lobe-free field of view with low-complexity co-prime photonic beamforming transceivers
Integrated photonic active beamforming can significantly reduce the size and cost of coherent imagers for LiDAR and medical imaging applications. In current architectures, the complexity of photonic and electronic circuitry linearly increases with the desired imaging resolution. We propose a novel photonic transceiver architecture based on co-prime sampling techniques that breaks this trade-off and achieves the full (radiating-element-limited) field of view (FOV) for a 2D aperture with a single-frequency laser. Using only order-of-N radiating elements, this architecture achieves beamwidth and sidelobe level (SLL) performance equivalent to a transceiver with order-of-N² elements with half-wavelength spacing. Furthermore, we incorporate a pulse amplitude modulation (PAM) row–column drive methodology to reduce the number of required electrical drivers for this architecture from order of N to order of √N. A silicon photonics implementation of this architecture using two 64-element apertures, one for transmitting and one for receiving, requires only 34 PAM electrical drivers and achieves a transceiver SLL of −11.3 dB with 1026 total resolvable spots, and 0.6° beamwidth within a 23°×16.3° FOV.
© 2022 Chinese Laser Press. Received 29 July 2021; revised 9 March 2022; accepted 24 March 2022; posted 25 March 2022 (Doc. ID 437518); published 29 April 2022. The authors acknowledge Behrooz Abiri and Parham Porsandeh Khial for their valuable inputs in the design and analysis of this work. The authors disclose no conflicts of interest. Data Availability: Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.
Submitted - 2108.10223.pdf
Published - prj-10-5-A66.pdf