Programmable Active Mirror: A Scalable Decentralized Router

This work proposes and demonstrates the scalable router array that eliminates the internal centralization of conventional arrays, unlocking scalability, and the potential for a system composed of spatially separated elements that do not share a common timing reference. Architectural variations are presented, and their specific tradeoffs are discussed. The general operation, steering capabilities, signal and noise considerations, and timing control advantages are evaluated through analysis, simulation, and measurements. An element-level CMOS radio frequency integrated circuit (RFIC) is developed and used to demonstrate a four-element 25 GHz prototype router. The RFIC's programmable true time delay (TTD) control is used to correct path-length-difference-induced intersymbol interference (ISI) and improve a rerouted 270-Mb/s 64-QAM constellation from a completely scrambled state to an EVM of 4% rms (-28 dB). The prototype scalable router's concurrent dual-beam capabilities are demonstrated by simultaneously steering two full power beams at 24.9 and 25 GHz in two different directions in a free-space electromagnetic setup

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

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 multi-mode 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

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

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 multi-mode 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

Nanophotonic optical gyroscope with reciprocal sensitivity enhancement

Optical gyroscopes measure the rate of rotation by exploiting a relativistic phenomenon known as the Sagnac effect. Such gyroscopes are great candidates for miniaturization onto nanophotonic platforms. However, the signal-to-noise ratio of optical gyroscopes is generally limited by thermal fluctuations, component drift and fabrication mismatch. Due to the comparatively weaker signal strength at the microscale, integrated nanophotonic optical gyroscopes have not been realized so far. Here, we demonstrate an all-integrated nanophotonic optical gyroscope by exploiting the reciprocity of passive optical networks to significantly reduce thermal fluctuations and mismatch. The proof-of-concept device is capable of detecting phase shifts 30 times smaller than state-of-the-art miniature fibre-optic gyroscopes, despite being 500 times smaller in size. Thus, our approach is capable of enhancing the performance of optical gyroscopes by one to two orders of magnitude

Design and Implementation of Reference-Free Drift-Cancelling CMOS Magnetic Sensors for Biosensing Applications

Magnetic imagers, which utilize magnetic nanoparticles as labels to realize biodetection assays, hold significant promise for deployment at the point-of-use. Resonance-shift-based sensors can be realized in standard CMOS processes without post-process modifications and offer great sensitivity at low price tags. Unfortunately, CMOS resonant-shift magnetic sensors suffer significant degradation in SNR and long-term stability due to low on-chip inductor quality factors and significant noise introduced from active devices and thermal variations. This makes standard resonant-shift-based imagers undesirable for use in low-signal biodetection assays. Furthermore, and most importantly, the significant long-term drift due to slow-varying noise sources and temperature changes makes these sensors inadequate for bioexperiments which may take timescales on the order of hours to reach completion. In this paper, we propose a transformer-based approach which enables sub-parts-per-million (PPM) signal detection without the need for any thermal compensation. The approach is self-referencing, leading to significant savings in chip area by removing the need for replica reference cells. We analyze the performance of the transformer-based circuit compared to the original second-order system and demonstrate its superiority for rejecting system noise. A proof-of-concept design of a fully integrated 2×2 CMOS transformer-based magnetic sensor array is presented which achieves reference-free, sub-PPM detection of magnetic signals. The system can be powered and operated completely from a laptop USB interface and each sensing cell can consume less than 3 mW of DC power. Finally, we show the results of an initial DNA biodetection experiment which confirms the capability of the sensor to be used for realistic bioassays

A Chip-Scale Nanophotonic Optical Gyroscope

This paper presents the first demonstration of a nanophotonic optical gyroscope (NOG) on a silicon-photonic platform. Reciprocal sensitivity enhancement is introduced as an effective method to overcome the limitations of NOGs

Design and Implementation of Reference-Free Drift-Cancelling CMOS Magnetic Sensors for Biosensing Applications

Magnetic imagers, which utilize magnetic nanoparticles as labels to realize biodetection assays, hold significant promise for deployment at the point-of-use. Resonance-shift-based sensors can be realized in standard CMOS processes without post-process modifications and offer great sensitivity at low price tags. Unfortunately, CMOS resonant-shift magnetic sensors suffer significant degradation in SNR and long-term stability due to low on-chip inductor quality factors and significant noise introduced from active devices and thermal variations. This makes standard resonant-shift-based imagers undesirable for use in low-signal biodetection assays. Furthermore, and most importantly, the significant long-term drift due to slow-varying noise sources and temperature changes makes these sensors inadequate for bioexperiments which may take timescales on the order of hours to reach completion. In this paper, we propose a transformer-based approach which enables sub-parts-per-million (PPM) signal detection without the need for any thermal compensation. The approach is self-referencing, leading to significant savings in chip area by removing the need for replica reference cells. We analyze the performance of the transformer-based circuit compared to the original second-order system and demonstrate its superiority for rejecting system noise. A proof-of-concept design of a fully integrated 2×2 CMOS transformer-based magnetic sensor array is presented which achieves reference-free, sub-PPM detection of magnetic signals. The system can be powered and operated completely from a laptop USB interface and each sensing cell can consume less than 3 mW of DC power. Finally, we show the results of an initial DNA biodetection experiment which confirms the capability of the sensor to be used for realistic bioassays