Focal Plane Array Based on Silicon Nitride for Optical Beam Steering at 2 Microns

The 2 μm wavelength is ideal for light detection and ranging and gas sensing due to its eye-safe operation, strong molecular absorption targeting, and low atmospheric scattering—critical for environmental monitoring and free-space communications. The existing 2 μm systems rely on mechanical beam ste...

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Bibliographic Details
Main Authors: Qing Gao, Jiaqi Li, Jincheng Wei, Jinjie Zeng, Dong Yang, Xiaoqun Yu, Mingshen Peng, Hongwen Xuan, Ruijun Wang, Yanfeng Zhang
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Photonics
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Online Access:https://www.mdpi.com/2304-6732/12/5/448
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Summary:The 2 μm wavelength is ideal for light detection and ranging and gas sensing due to its eye-safe operation, strong molecular absorption targeting, and low atmospheric scattering—critical for environmental monitoring and free-space communications. The existing 2 μm systems rely on mechanical beam steering, which limits speed and reliability. Integrated photonic solutions have not yet been demonstrated in this wavelength. We propose a focal plane array design to address these challenges. Compared to optical phased arrays requiring complex phase control for each antenna, FPAs have a simple switch-based control and high suppression of background noise. Although FPAs need an external lens for beam collimation, they significantly reduce system complexity. This study introduces a compact, low-loss 1 × 8 focal plane array operating in the 2 μm range, employing a cascaded Mach–Zehnder interferometer switch array on a silicon nitride platform. The device demonstrates a field of view of 16.8°, background suppression better than 17 dB, and excess loss of −1.4 dB. This integrated photonic beam steering solution offers a highly promising, cost-effective approach for rapid beam switching. This integrated photonic beam steering solution offers a highly promising, cost-effective approach for rapid beam switching.
ISSN:2304-6732