A one femtojoule athermal silicon modulator

Silicon photonics has emerged as the leading candidate for implementing ultralow power wavelength division multiplexed communication networks in high-performance computers, yet current components (lasers, modulators, filters, and detectors) consume too much power for the femtojouleclass links that will ultimately be required. Here, we propose, demonstrate, and characterize the first modulator to achieve simultaneous high-speed (25-Gb/s), low voltage (0.5VPP) and efficient 1-fJ/bit error-free operation while maintaining athermal operation. Both the low energy and athermal operation were enabled by a record free-carrier accumulation/depletion response obtained in a vertical p-n junction device that at 250-pm/V (30-GHz/V) is up to ten times larger than prior demonstrations. Over a 7.5{\deg}C temperature range, the massive electro-optic response was used to compensate for thermal drift without increasing energy consumption and over a 10{\deg}C temperature range, increasing energy consumption by only 2-fJ/bit. The results represent a new paradigm in modulator development, one where thermal compensation is achieved electro-optically.Comment: 23 pages, 5 figure

Microfluidics for Biosensing and Diagnostics

Efforts to miniaturize sensing and diagnostic devices and to integrate multiple functions into one device have caused massive growth in the field of microfluidics and this integration is now recognized as an important feature of most new diagnostic approaches. These approaches have and continue to change the field of biosensing and diagnostics. In this Special Issue, we present a small collection of works describing microfluidics with applications in biosensing and diagnostics

Optical fiber sensors in physical intrusion detection systems: A review

Fiber optic sensors have become a mainstream sensing technology within a large array of applications due to their inherent benefits. They are now used significantly in structural health monitoring, and are an essential solution for monitoring harsh environments. Since their first development over 30 years ago, they have also found promise in security applications. This paper reviews all of the optical fiber-based techniques used in physical intrusion detection systems. It details the different approaches used for sensing, interrogation, and networking, by research groups, attempting to secure both commercial and residential premises from physical security breaches. The advantages and the disadvantages of the systems are discussed, and each of the different perimeter protection methods is outlined, namely, in-ground, perimeter fence, and window and door protection. This paper reviews the progress in optical fiber-based intrusion detection techniques from the past through to the current state-of-the-art systems and identifies areas, which may provide opportunities for improvement, as well as proposing future directions in this field

Modeling, simulation and testing of a silicon soil moisture sensor based on the dual-probe heat-pulse method

A silicon soil moisture sensor, based in the dual-probe heat-pulse (DPHP) method, was modeled, simulated and tested for achieving, with low-cost, accurate and reliable measurements. This method is based on the application of a heat pulse during a fixed interval of time. The maximum rise in temperature (ΔTM) is monitored by the measurement probe, placed at a certain distance of the heater source. A low-cost high-performance and small temperature sensor (a dynamic VPTAT generator) was designed and fabricated to be placed into the probe which have 0.912 mm inner diameter and 20 mm long. If one considers the range of water contents, ratio of water mass to dry soil mass, in a typical agricultural soil (0.05–0.35m3 m−3), the average sensitivity of the dual probe is about 1.95º C per unit change (m3 m−3) in water content for q = 400 Jm−1

On-chip integrated silicon bulk-micromachined soil moisture sensor based on the DPHP method

This paper reports the design, modelling, fabrication and assembly of a silicon bulk-micromachined soil moisture microsensor using the Dual-Probe Heat-Pulse (DPHP) method. Soil humidity measurement is essential to studysoil preservation and control the development of plants, namely in closed ecosystem. The DPHP method uses a heater (Peltier effect) and a temperature probe (Seebeck effect) to determine the volumetric heat capacity of the soil and hence water content ( θv). This is the first time that the DPHP method is implemented in a microdevice and the first integrated sensor for soil moisture. This microdevice is more suited to measure at different soil depths in a non-destructive and automated manner.Agricultural and Agro-industrial Science and Technology Institute of the University of Trás-os-Montes and Alto Douro

Objective method for measuring the macular pigment optical density in the eye

Macular pigment is a yellowish pigment of purely dietary origin, which is thought to have a protective role in the retina. Recently, it was linked to age-related macular degeneration and improved visual function. In this work, we present a method and a corresponding optical instrument for the rapid measurement of its optical density. The method is based on fundus reflectometry and features a photodetector for the measurement of reflectance at different wavelengths and retinal locations. The method has been tested against a commercially available instrument on a group of healthy volunteers and has shown good correlation. The proposed instrument can serve as a rapid, non-midriatic, low-cost tool for the measurement of macular pigment optical density

암 진단 및 치료에 적용 가능한 마이크로파 능동 집적 탐침에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 2. 권영우.본 논문에서는 암 진단 및 치료에 적용 가능한 초소형 마이크로파 능동 집적 탐침에 대해 기술하였다. 생체 조직의 광대역 측정과 저전력 온열 치료에 적용 하기 위해 유전율 측정 회로를 평면형 동축 탐침에 집적하였고, 마이크로파 발생 회로를 어플리케이터에 집적하였다. MEMS 기술과 MMIC 기술을 적용함으로써 단일 플랫폼에 집적된 시스템으로 구현하여 집적도를 향상 시키고, 시스템을 소형화 하였다. 먼저 multi-state reflectometer를 이용하여 암 진단에 활용 가능한복소 유전율 측정 기술에 대해 제안하였다. 2, 16 GHz에서 동작하는 광대역 reflectometer는 이중 대역 위상 고정 루프 (PLL), 임피던스 튜너, RF 전력 검출기 등의 MMIC와 MEMS 기반의 방향성 결합기, 평면형 탐침을 집적하여 구현하였다. 제작한 능동 집적 탐침 시스템을 이용하여 생체 조직과 암 조직 등의 유전율을 측정함으로써 유용함을 확인하였고, 측정된 유전율과 표준값을 비교하여 시스템의 측정 정확도를 검증하였다. 또한 저전력 마이크로파 온열 치료 요법을 위한 능동 집적 탐침을 개발하였다. MEMS 공정을 통해 제작한 평면형 실리콘 탐침에 전압 제어 발진기, 구동 증폭기, 전력 증폭기를 집적하여 능동 집적 탐침 시스템을 제작하였다. 치료를 진행하는 동안, 마이크로파의 전력을 측정할 수 있도록 전력 검출기와 방향성 결합기도 함께 집적하였다. 암, 근육 등 다양한 생체 조직을 이용한 실험의 결과로부터 Ku 대역의 주파수에서 저전력 마이크로파 온열 치료가 가능함을 확인하였다. 마지막으로 자성 나노입자를 이용한 온열 치료에 적용하기 위해 능동 집적 탐침을 개발하였다. 자성 나노입자가 온열 치료 요법에 미치는 영향을 분석하기 위해 전자기-열 결합 해석을 수행하였고, 이로부터 자성 나노입자의 선택도 향상을 위한 최적의 주파수를 결정하였다. 발진기와 전력 증폭기 MMIC와 이중 채널 로그 전력 검출기, 방향성 결합기를 탐침에 집적하여 시스템을 제작하였다. 이를 이용한 실험 결과로부터 능동 집적 탐침의 성능을 확인하였으며, 자성 나노입자가 저전력 및 암 특이 마이크로파 온열 치료의 효율과 선택도를 향상시키는데 유용함을 검증하였다.This thesis presents miniaturized microwave active integrated probe systems applicable to cancer detection and treatment. To realize broadband detection and low-power hyperthermia, planar-type coaxial probes and heat applicators have been integrated with active circuits for permittivity measurement and microwave generation, respectively. Each integrated system is implemented on a single platform using Microelectromechanical Systems (MEMS) and monolithic microwave integrated circuit (MMIC) technologies for miniaturization and integration. First, a complex permittivity measurement technique using an integrated multi-state reflectometer (MSR) is proposed for cancer detection application. The broadband MSR covering both 2 and 16 GHz bands consists of a dual-band phase-locked loop, a directional coupler, an impedance tuner, two RF power detectors, and a micromachined silicon planar probe with an open-ended coaxial aperture. All the active and passive circuit components have been integrated on the micromachined probe platform in a small form factor of 6.8 mm × 50 mm × 0.6 mm. The performance of the fabricated integrated probe has been evaluated by comparing the measured permittivities of 0.9% saline, pork muscle, fat, and xenografted human breast cancer with the reference data. For low-power microwave hyperthermia, a Ku-band active integrated heat applicator is demonstrated. A planar-type coaxial applicator has been fabricated using silicon micromachining technology, on which a Ku-band voltage controlled oscillator (VCO), a driver amplifier, and a power amplifier (PA) have been integrated. A directional coupler and power detectors are employed for power monitoring. The fully integrated heat applicator has been realized in a small footprint of 8 mm × 56 mm. In-vitro and in-vivo ablation experiments on pork muscle, fat, and human-cancer xenografted nude mouse demonstrate the feasibility of low-power hyperthermia using Ku-band microwaves. Finally, an active integrated heat applicator for magnetic nanoparticle (MNP)-assisted hyperthermia is developed. The effect of the MNP on microwave hyperthermia has been analyzed by a coupled electromagnetic-thermal analysis. The optimum frequency for hyperthermia is determined by the coupled analysis. A 2-GHz source module consisting of a VCO and a PA has been implemented in MMICs and integrated on the heat applicator platform. A dual-channel log detector and a directional coupler have been also employed to monitor the power levels during hyperthermia. Experiment results show not only sufficient heating performance of the integrated applicator, but also the effectiveness of the MNP for low-power and cancer-specific microwave hyperthermia.Abstract i Contents iv List of Figures viii List of Tables xv 1. Introduction 1 1.1 Motivation 1 1.2 Microwave Cancer Detection 4 1.3 Microwave Hyperthermia 5 1.4 Outline of Thesis 7 2. Active Integrated Probe for Cancer Detection 9 2.1 Introduction 9 2.2 Principle of Operation 13 2.2.1 Multi-State Reflectometer 14 2.2.2 Governing Equation for Complex Permittivity 15 2.2.3 Determination of Complex Permittivity 17 2.2.4 Calibration 19 2.3 Design and Fabrication 21 2.3.1 Micromachined Planar Coaxial Probe 21 2.3.2 Impedance Tuner 30 2.3.3 Directional Coupler 34 2.3.4 Power Detector 37 2.3.5 Signal Source 39 2.3.6 Active Integrated Probe System 43 2.4 Measurement Results 46 2.5 Summary 52 3. Ku-Band Active Integrated Heat Applicator for Cancer Ablation 54 3.1 Introduction 54 3.2 Design and Fabrication 57 3.2.1 Micromachined Planar Coaxial Applicator 58 3.2.2 Microwave Source 63 3.2.3 Power Monitoring Circuits 67 3.2.4 Ku-Band Active Integrated Applicator System 67 3.3 Experiment Results 70 3.4 Summary 77 4. Active Integrated Heat Applicator for Magnetic Nanoparticle-Assisted Hyperthermia 79 4.1 Introduction 79 4.2 Magnetic Nanoparticle (MNP) 82 4.2.1 Heating mechanism of MNP 83 4.2.2 Permeability of MNP 84 4.3 Coupled Electromagnetic-Thermal Analysis 88 4.3.1 Coupled Electromagnetic-Thermal Problems 88 4.3.2 Electromagnetic Analysis 92 4.3.3 Thermal Analysis 94 4.3.4 Analysis Results 96 4.4 Design and Fabrication 103 4.4.1 Spiral Applicator 104 4.4.2 Microwave Source 107 4.4.3 Power Monitoring Circuits 111 4.4.4 Active Integrated Applicator for MNP-Assisted Hyperthermia 119 4.5 Experiment Results 122 4.6 Summary 132 5. Conclusion 134 Bibliography 137 Abstract in Korean 152Docto

Integrated Bragg gratings in silicon-on-insulator

Dans la littérature, les réseaux de Bragg intégrés sur silicium sont relativement simples par rapport à leurs contreparties fibrées. Cependant, la fabrication de réseaux plus élaborés permettrait d’améliorer la capacité de traitement du signal des circuits sur silicium. Cette thèse s’attarde donc aux difficultés encourues lors de la conception, de la fabrication et de la caractérisation de réseaux de Bragg sur silicium ayant une réponse spectrale élaborée. Tout d'abord, afin de caractériser la réponse spectrale complexe des réseaux, l’utilisation de filtrage temporel est proposée afin de supprimer les réflexions parasites. Cela a permis d’utiliser des algorithmes de reconstruction fournissant une caractérisation complète de ces structures. De plus, l’ajout d’un filtrage des hautes fréquences spatiales a permis de réduire considérablement le bruit des mesures. Par la suite, les principales sources de distorsions de la réponse spectrale des réseaux ont été identifiées, soit la rugosité des guides et la variation de leur épaisseur. L’impact de ces phénomènes a été étudié numériquement et analytiquement et, pour la première fois, la longueur de corrélation de ces sources de bruit a été caractérisée expérimentalement sur une longueur suffisante. Finalement, deux techniques permettant de diminuer l’impact de ces phénomènes ont été proposées, ce qui a permis de fabriquer les réseaux de Bragg sur silicium ayant la plus petite largeur de bande publiée à ce jour. Également, nous avons fait les premières démonstrations d’apodisation de réseaux de Bragg utilisant uniquement la phase de ces derniers (c.-à-d. apodisation en phase et par superposition). Contrairement aux techniques déjà proposées, ces dernières ont l'avantage de ne pas introduire de distorsions de l'indice effectif, ils sont plus robuste aux erreurs de fabrication et sont compatibles avec l’apodisation de réseaux à corrugations de très petites amplitudes. Finalement, afin d'augmenter la longueur des réseaux tout en gardant leur dimension compatible avec la taille des puces de silicium, les réseaux ont été courbés en forme de spirale compacte. Pour ce faire, la période des réseaux a été modifiée afin de compenser l'effet de la courbure sur l'indice effectif. Ainsi, nous avons démontré que des réseaux de 2 mm de long pouvaient être intégrés sur une surface de 200 µm x 190 µm sans ajout de dégradation spectrale et, surtout, sans restriction sur la structure du design. Ces résultats sont significatifs, car un contrôle précis de la phase et de l’amplitude des réseaux combinés avec la capacité de fabriquer de réseaux longs sont nécessaire afin de réaliser des filtres optiques intégrés avec des réponses spectrales élaborées. Ainsi, le travail présenté dans cette thèse ouvre la porte à de nouveaux designs à base de réseaux de Bragg.In the literature, integrated Bragg gratings in Silicon-on-Insulator are relatively simple compared to their fibre Bragg grating counterpart. However, elaborate gratings could improve the signal processing capability of the silicon platform. Thus, this thesis addresses the issues that prevent the design, the fabrication and the characterization of Bragg gratings having elaborate spectral response in the silicon platform. Firstly, in order to precisely characterize Bragg gratings complex spectral response, we proposed to suppress parasitic reflections using temporal filtering. The results obtained with measurement technique, when used with an integral layer peeling algorithm, allowed us to retrieve the amplitude and phase profiles of the grating thus providing a complete characterization of the structure. Moreover, the addition of a low-pass spatial filter allowed improving the characterization process by reducing the measurement noise. Secondly, the main sources of distortion of Bragg gratings spectral response have been identified to be the sidewall roughness and the wafer height fluctuation. An exhaustive study of the impact of these phenomena has been done both numerically and analytically. Furthermore, for the first time, the autocorrelation of these noise sources has been characterized experimentally on a sufficient length. Finally, improvements in the waveguide designs have reduced significantly these effects which allowed the fabrication of Bragg gratings in silicon with the smallest bandwidth published to date. Thirdly, the first demonstration of apodized Bragg gratings using only phase modulation of the structure has been done (i.e. phase apodisation and superposition apodisation). Unlike already published techniques, the later ones have the advantage to be robust to deep-UV lithography and fabrication errors. Furthermore, they do no introduce distortions into the grating phase profile and they are compatible with gratings having small recesses. Finally, in order to increase the grating length while keeping their dimension compatible with the silicon chip size, we proposed to bend them in a compact spiral shape. To do this properly, the curvature impact on the effective index has been modeled and compensated successfully by modifying the grating period. Thus, we have shown that 2 mm long gratings can be integrated on a surface of 200 µm x 190 µm without the addition of spectral degradation and without restrictions on the design structure. These results are of importance because longer grating structures with weaker coupling coefficients and a precise control both on its phase and amplitude are required in order to achieve integrated optical filters with elaborate spectral responses. Thus, we believe that the work presented in this thesis open the door to many new grating-based optical filter designs compatible with integrated optics technologies

Millimeter-Precision Laser Rangefinder Using a Low-Cost Photon Counter

In this book we successfully demonstrate a millimeter-precision laser rangefinder using a low-cost photon counter. An application-specific integrated circuit (ASIC) comprises timing circuitry and single-photon avalanche diodes (SPADs) as the photodetectors. For the timing circuitry, a novel binning architecture for sampling the received signal is proposed which mitigates non-idealities that are inherent to a system with SPADs and timing circuitry in one chip