Electromagnetic Field Manipulation: Biosensing to Antennas

We will explore how understanding and controlling electromagnetic fields can provide significant impact across a multitude of applications throughout the whole frequency spectrum from DC to daylight. Starting from the DC end of the electromagnetic spectrum, we motivate the design of a new integrated magnetic biosensing design as well as various improvements to the initial design based on spatial and temporal manipulations of the magnetic fields. Next, we look into the RF domain and develop maximal performance bounds for antennas and other electromagnetic structures. We develop rapid simulation techniques which when coupled with heuristic optimization algorithms can quickly and effectively produce new antenna structures with little to no manual intervention. We demonstrate the efficacy of these techniques in the context of on-chip antenna designs and a 3D printed coupling antenna for a dielectric waveguide communication link. We present the design of a 120GHz dual-channel 100Gbps QPSK/64QAM transceiver IC developed in a standard 28nm bulk CMOS process. Finally, we explore the higher THz regime in the context of photonic device optimization. We optimize compact photonic multiplexer devices which are fabricated in a standard foundry process and evaluate their performance against simulation results

A CMOS Broadband Power Amplifier With a Transformer-Based High-Order Output Matching Network

A transformer-based high-order output matching network is proposed for broadband power amplifier design, which provides optimum load impedance for maximum output power within a wide operating frequency range. A design methodology to convert a canonical bandpass network to the proposed matching configuration is also presented in detail. As a design example, a push-pull deep class-AB PA is implemented with a third-order output network in a standard 90 nm CMOS process. The leakage inductances of the on-chip 2:1 transformer are absorbed into the output matching to realize the third-order network with only two inductor footprints for area conservation. The amplifier achieves a 3 dB bandwidth from 5.2 to 13 GHz with +25.2 dBm peak P_sat and 21.6% peak PAE. The EVM for QPSK and 16-QAM signals both with 5 Msample/s are below 3.6% and 5.9% at the output 1 dB compression point. This verifies the PA’s capability of amplifying a narrowband modulated signal whose center-tone can be programmed across a large frequency range. The measured BER for transmitting a truly broadband PRBS signal up to 7.5 Gb/s is less than 10^(-13) , demonstrating the PA’s support for an instantaneous wide operation bandwidth

A Frequency-Shift based CMOS Magnetic Biosensor with Spatially Uniform Sensor Transducer Gain

This paper presents a scalable and ultrasensitive magnetic biosensing scheme based on on-chip LC resonance frequency-shifting. The sensor transducer gain is demonstrated as being location-dependent on the sensing surface and proportional to the local polarization magnetic field strength |B|^2 generated by the sensing inductor. To improve the gain uniformity, a bowl-shape stacked coil together with floating shimming metal is proposed for the inductor design. As an implementation example, a 16-cell sensor array is designed in a 45nm CMOS process. The spatially uniform sensor gain of the array is verified by testing micron-size magnetic particles randomly placed on the sensing surface. The Correlated-Double-Counting (CDC) noise cancellation scheme is also implemented in the presented design, which achieves a noise suppression of 10.6dB with no power overhead. Overall, the presented sensor demonstrates a dynamic range of at least 85.4dB

Ultrafast Simulation and Optimization of Nanophotonic Devices with Integral Equation Methods

Integrated photonics is poised to become a billion-dollar industry due to its vast array of applications. However, designing and modeling photonic devices remains challenging due to the lack of analytical solutions and difficulties with numerical simulation. Recently, inverse design has emerged as a promising approach for designing photonic devices; however, the current implementations require major computational effort due to their use of inefficient electromagnetic solvers based on finite-difference methods. Here we report a new, highly efficient method for simulating devices based on boundary integral equations that is orders of magnitude faster and more accurate than existing solvers, almost achieves spectral convergence, and is free from numerical dispersion. We develop an optimization framework using our solver based on the adjoint method to design new, ready-to-fabricate devices in just minutes on a single-core laptop. As a demonstration, we optimize three different devices: a nonadiabatic waveguide taper, a 1:2 1550 nm power splitter, and a vertical-incidence grating coupler

An ultrasensitive CMOS magnetic biosensor array with correlated double counting noise suppression

This paper presents a scalable and ultrasensitive frequency-shift magnetic biosensing array scheme. The theoretical limit of the sensor noise floor is shown to be dominated by the phase noise of the sensing oscillators. To increase the sensitivity, a noise suppression technique, Correlated Double Counting (CDC), is proposed with no power overhead. As an implementation example, a 64-cell sensor array is designed in a standard 65nm CMOS process. The CDC scheme achieves an additional 6dB noise suppression. The magnetic sensing capability of the presented sensor is verified by detecting micron size magnetic particles with an SNR of 14.6dB for a single bead and an effective dynamic range of at least 74.5dB

Binary particle swarm optimized 2 × 2 power splitters in a standard foundry silicon photonic platform

Compact power splitters designed ab initio using binary particle swarm optimization in a 2D mesh for a standard foundry silicon photonic platform are studied. Designs with a 4.8  μm×4.8  μm footprint composed of 200  nm×200  nm and 100  nm×100  nm cells are demonstrated. Despite not respecting design rules, the design with the smaller cells had lower insertion losses and broader bandwidth and showed consistent behavior across the wafer. Deviations between design and experiments point to the need for further investigations of the minimum feature dimensions

Nonlinear Nanophotonic Devices in the Ultraviolet to Visible Wavelength Range

Although the first lasers invented operated in the visible, the first on-chip devices were optimized for near-infrared (IR) performance driven by demand in telecommunications. However, as the applications of integrated photonics has broadened, the wavelength demand has as well, and we are now returning to the visible (Vis) and pushing into the ultraviolet (UV). This shift has required innovations in device design and in materials as well as leveraging nonlinear behavior to reach these wavelengths. This review discusses the key nonlinear phenomena that can be used as well as presents several emerging material systems and devices that have reached the UV–Vis wavelength range