Inverse Design and Demonstration of Broadband Grating Couplers

Sapra, Neil V.; Vercruysse, Dries; Su, Logan; Yang, Ki Youl; Skarda, Jinhie; Piggott, Alexander Y.; Vučković, Jelena

doi:10.1109/jstqe.2019.2891402

Cited by 80 publications

(45 citation statements)

References 34 publications

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“…29 The total transmission loss is estimated at above 30 dB, and can be significantly improved with the use of more efficient grating couplers. 30 Figure 7a shows tuning spectra where one of the three cavities (whose In summary, we have implemented a thermally tunable hybrid photonic architecture suitable for coherent interaction of free-space light and tunable GaAs photonic crystal cavities facilitated by SiN x bus-waveguide terminated by grating couplers. We show excellent thermal tuning performance using custom-designed microheaters.…”

Section: Resultsmentioning

confidence: 99%

Thermally Tunable Hybrid Photonic Architecture for Nonlinear Optical Circuits

et al. 2018

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Integrated photonic systems are a leading solution for fast and energy-efficient information processing. We develop a thermally tunable hybrid photonic platform for implementation of coherent optical networks applicable to dedicated computing and machine learning. The hybrid architecture comprises gallium arsenide (GaAs) photonic crystal cavities, silicon nitride (SiN x ) grating couplers and waveguides, and chromium (Cr) microheaters on an integrated photonic chip. We utilize the band-edge nonlinearity in GaAs photonic crystal cavity for switching at 6 ps timescale. The cavities are evanescently connected to a common bus waveguide, separating the computation and communication layers. To synchronize the operating frequency, we design metal microheaters that locally, continuously and reversibly tune photonic crystal cavities to a common resonance. We demonstrate 7 nm tunability range with no significant quality factor deterioration. By coupling the free-space light to the photonic chip, we demonstrate the tunable interaction of the propagating signal with three nonlinear optical nodes.

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Section: Resultsmentioning

confidence: 99%

Thermally Tunable Hybrid Photonic Architecture for Nonlinear Optical Circuits

et al. 2018

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“…Furthermore, the built-in directionality of the custom integrated photonics microgratings can serve as a means of enhancing the computational image-recovery performance. These diffraction gratings can be engineered to have sensitivity in nearly arbitrary patterns and to admit a large span of wavelengths 11,12 , and as we show, can respond to incoherent light as well as coherent light. Using micrograting couplers co-designed with computational processing, we demonstrate that silicon photonics is a viable platform for computational imaging using a prototype lensless imaging device.…”

mentioning

confidence: 87%

A Silicon Photonics Computational Lensless Active-Flat-Optics Imaging System

White

Khial

Salehi

et al. 2020

Sci Rep

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the need for lightweight, miniature imaging systems is becoming increasingly prevalent in light of the development of wearable electronics, iot devices, and drones. computational imaging enables new types of imaging systems that replace standard optical components like lenses with cleverly designed computational processes. traditionally, many of these types of systems use conventional complementary metal oxide semiconductor (cMoS) or charge coupled device (ccD) sensors for data collection. While this allows for rapid development of large-scale systems, the lack of system-sensor codesign limits the compactness and performance. Here we propose integrated photonics as a candidate platform for the implementation of such co-integrated systems. Using grating couplers and co-designed computational processing in lieu of a lens, we demonstrate the use of silicon photonics as a viable platform for computational imaging with a prototype lensless imaging device. the proof-of-concept device has 20 sensors and a 45-degree field of view, and its optics and sensors are contained within a 2,000 μm × 200 μm × 20 μm volume.

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“…However, since the antenna is fed from one side, the field distribution might deviate from an ideal periodic pattern. While using a grating structure is a straight forward technique to achieve a distribution, other designs obtained by aperiodic and irregular apertures have been also demonstrated recently [4], [18], [25].…”

Section: Fabrication Imposed Limitationsmentioning

confidence: 99%

Breaking FOV-Aperture Trade-Off With Multi-Mode Nano-Photonic Antennas

Fatemi

Khial

Khachaturian

et al. 2021

IEEE J. Select. Topics Quantum Electron.

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Nano-photonic antennas are one of the key components in integrated photonic transmitter and receiver systems. Conventionally, grating couplers, designed to couple into an optical fiber, suffering from limitations such as large footprint and small field-of-view (FOV) have been used as on-chip antennas. The challenge of the antenna design is more pronounced for the receiver systems, where both the collected power by the antenna and its FOV often need to be maximized. While some novel solutions have been demonstrated recently, identifying fundamental limits and trade-offs in nano-photonic antenna design is essential for devising compact antenna structures with improved performance. In this paper, the fundamental electromagnetic limits, as well as fabrication imposed constraints on improving antenna effective aperture and FOV are studied, and approximated performance upper limits are derived and quantified. By deviating from the conventional assumptions leading to these limits, high-performance multi-mode antenna structures with performance characteristics beyond the conventional perceived limits are demonstrated. Finally, the application of a pillar multimode antenna in a dense array is discussed, an antenna array with more than 95% collection efficiency and 170°FOV is demonstrated, and a coherent receiving system utilizing such an aperture is presented.

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Inverse Design and Demonstration of Broadband Grating Couplers

Cited by 80 publications

References 34 publications

Thermally Tunable Hybrid Photonic Architecture for Nonlinear Optical Circuits

Thermally Tunable Hybrid Photonic Architecture for Nonlinear Optical Circuits

A Silicon Photonics Computational Lensless Active-Flat-Optics Imaging System

Breaking FOV-Aperture Trade-Off With Multi-Mode Nano-Photonic Antennas

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