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This paper presents a fully integrated wireless sensor brain machine interface system to restore continuous somatosensory feedback from the hand. A wireless bi-directional neural interface system-on-chip (SoC) and a wireless sensor node design are described in this work. The neural interface integrates a 16-channel neural recording front-end, a 16-channel electrical stimulation back-end, a successive approximation analog-to-digital converter (ADC), a custom digital controller, and an ultra-wide band (UWB) wireless transceiver. The sensor node features a custom designed optical force sensor, a low-power level-crossing ADC, an UWB transmitter, and analog interface to off-chip accelerometers. The optical force sensor is developed in standard CMOS with low-cost post fabrication. Multiple sensor nodes can be used to trigger pre-defined microstimulation in different brain areas for restoring finger sensation. The prototypes have been fabricated in 180nm standard CMOS technology. Bench testing and In-Vivo experimental results are presented in this paper. The system was designed to investigate the first chronic interface to the cuneate nucleus of macaques, and showed a promising solution for sensation restoration in future neuroprosthetics.

This paper presents a novel neuroprosthetic system for perception encoding. The system consists of a wireless waterproof bi-directional neural interface and an object tracking image sensor. The neural interface features a fully programmable 8-channel neural stimulator, a compliance voltage and impedance monitoring module, a 16-channel neural recording front-end, and a duplex wireless transceiver. The image sensor features a 180×180 pixel array, with in-pixel comparator for energy efficient color thresholding based object detection tracking. A unique experiment was designed in which rats navigate a water maze using only brain stimulation to inform their location relative to a hidden platform. Custom hardware and software have been developed to support the investigation, with special attention paid to the safety of the animals during the experiment. The proposed chip designs have been fabricated in 180nm CMOS technology. This work demonstrates a novel experimental paradigm, and that the developed wireless neuroprosthetic system can be used to conduct extensive sensory encoding experiments in freely behaving animals.

In this paper, a bioinspired monolithic complementary metal-oxide-semiconductor (CMOS) polarization image sensor is described as a solution to real-time polarization image capture. Metallic wire-grid gratings are integrated onto standard CMOS image sensor arrays with different orientations. A numerical analysis is performed to guide the design of the wire-grid arrays. Experimental results from different CMOS processing units are compared. A current-mode polarization processing unit is designed, fabricated, and tested in order to perform the extraction of the polarization characteristics from the captured intensities. This paper illustrates how polarization image processing can be used to monitor live cells. Several polarization processing methods with different computational complexity and data requirements have been applied and compared.

Current mode active pixel sensors convert light intensity into an analog output current. A current mode image sensor enables simple implementation of focal plane algebraic functions but suffers from poor linearity and large fixed-patten noise. This paper analyzes the causes of the non-linearity of a current-mode image sensor including a theoretical derivation and numerical simulation. Previously reported linearity improvement methods are reviewed, while an architecture of a current mode image sensor with a voltage feedback loop between pixel output and the current conveyor for linearity enhancement is proposed. An image sensor array of 100 $\times$ 200 current mode pixels is fabricated in a 0.5 $\mu{\rm m}$ 2P3M standard CMOS processing technology. Experimental results illustrate a 45% improvement of the linearity of the proposed imager. Fixed pattern noise is reduced by 57.6% for the maximum readout current, which can be further reduced by another 51.5% after gain calibration. A signal to noise ratio of 49.6 dB is achieved.

In this paper, we report on an image sensor with an integrated focal-plane 2 × 2 wire-grid polarizer for the visible spectrum, fabricated in a 65-nm standard CMOS technology. This imager enables the reconstruction of the polarization response for each pixel. Finite-difference time-domain method has been used to optimize the extinction ratio (ER) in the visible spectrum of a multilayered focal-plane wire-grid polarizer. Experimental results show that an ER of 16.35 dB is achieved with a standard error of ~ 0.25% between the experimental results and the fitting sinusoidal polarization response curve. Design guidelines for the wire-grid polarizer are derived based on numerical analysis and experimental results. Sensitivity ratio is defined to balance the tradeoff between the intensity sensitivity and polarization sensitivity of the imager.

A voltage controlled MEMS oscillator (VCMO) fabricated in 65nm CMOS process is proposed in this paper. The piezoelectric aluminum nitride (AlN) Contour-Mode MEMS resonator based oscillator can be operated under multiple frequencies from 204MHz, to 517MHz, to 850MHz. A maximum overall tuning range of 611ppm is achieved at a center frequency of 204MHz. The proposed oscillator operates in the sub-threshold region, resulting in a power consumption of 47μW measured under a 0.55V power supply, which is the lowest reported in literature for an application in the 200MHz range. The measured oscillator phase noise is -77dBc/Hz at 1kHz offset from the 204MHz carrier.

The need for more bandwidth driven by streaming video and other data intensive applications has been steadily pushing the optical link speed to the 40G/100G domain. Compared to VCSEL and ring resonator, Mach-Zehnder Interferometer (MZI) is the best solution for long distance (>500m), high data rate (>28Gb/s) optical communications [1-3]. However, high power consumption, low link density and high cost seriously prevent traditional MZI from being the next generation of optical link technology. To fundamentally reduce the cost of MZI, it is highly desirable to make the process CMOS compatible with high efficiency, thus the modulation voltage, size, and power can be reduced to a level where advanced sub-1V CMOS circuits can be used as the driver. This paper presents two CMOS-MZI-based optical transmitters, NRZ or configurable PAM-N (N = 4,16), featuring 20Gb/s data rate and sub-pJ/bit modulation energy (PAM-4) using a 1V supply. The fully CMOS compatible photonic device is highly cost-effective in terms of integration, manufacturability and scalability.

Current mode image sensors enable an easy implementation of focal plane algebraic functions, but suffer from poor linearity performance. A theoretical analysis is first performed on the source of the non-linearity for current mode image sensors. According to the analysis, an architecture of a current mode image sensor with a voltage feedback loop between pixel output and the current conveyor for linearity enhancement is proposed. An image sensor array of 100 × 200 current mode pixels is fabricated in 0.5um 2P3M standard CMOS processing technology. Experimental results illustrate a 45% improvement of the linearity of the proposed imager. Fixed pattern noise is reduced by 19% at the saturation level and signal to noise ratio of 49.6dB is achieved.

Some animals, such as crustaceans, arthropods, insects and aquatic creatures can detect a characteristic of light - polarization, that is invisible to humans. Different approaches of polarization imaging in the visual region have been proposed in the literature that employ precise but bulky optical devices. In recent years, taking advantage of nano-fabrication, researchers began integrating polarization films at the focal plane of standard image sensors. In addition, the development of nano-scale CMOS technology enables the integration of a standard pixel array with metallic wire-grid at the scale of the wavelength of visible light. Monolithic wire-grid polarization image sensor designs have been reported in the last few years, which is promising to be employed as a compact, portable, smart polarization detection device to extend the human visual ability.

Polarization is one of the important characteristics of visible light that can not be detected by human visual system or traditional image sensors. In this paper, we report on an image sensor integrated focal plane 2 × 2 wire-grid polarizer filter mosaic targeted at visible spectrum fabricated in 65nm standard CMOS processing line, which enables the reconstruction of the polarization response characteristic for each pixel. Finite-Difference Time-Domain method has been used for the first time to optimize the extinction ratio in visible spectrum of the multilayer focal plane wire-grid polarizer. Experimental results show that an extinction ratio around 10 is achieved with a standard error of around 0.25% between the experimental results and the fitting sinusoidal polarization response curve. A phase error at the level of less than 2% to the measurement phase resolution is achieved. These results are the best reported for a monolithic wire-grid polarization image sensor design for visible spectrum.