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Efficiency is always a major motivator behind technological advances. In lighting, it has prompted the wide adoption of solid-state light sources. When coupled with fluorescent materials, solid-state sources such as light emitting diodes are one of the most efficient white light sources available. For high brightness applications, such as projection systems, car headlights and large outdoor area illumination, laser diodes are a very promising alternative for LEDs thanks to their higher efficiency at high optical density output. Commercial applications of laser lighting (such as car headlights) are already entering the market, and this trend is predicted to continue as we strive for more efficient and higher brightness light sources.Despite its promising features, there is a major obstacle on the path towards the wide adoption of laser lighting. The fluorescent materials used to generate white light in combination with laser diodes are known to self-heat when exposed to the very bright laser diode light. As fluorescent materials heat up, their colour conversion efficiency rapidly decreases. This always leads to a non-stable white light system, and occasionally to the irreversible degradation of the fluorescent material itself. Surprisingly, the tools that are available to design such types of phosphor-converted light sources do not account for these effects. This means that any predictions obtained with these simulation tools regarding the performance of such white light sources are incorrect. To accurately model the phenomena previously described, it is necessary to model not only the system's optical properties but also their thermal properties -- and, perhaps most importantly, how they interact with one another.The goal of this research was on developing an efficient and general opto-thermal simulation framework to tackle the fluorescent self-heating issue. This way, it becomes possible to simulate the performance of a white light source based on laser diodes while considering all the relevant optical and thermal dependencies that affect fluorescent colour converting materials. Such a comprehensive opto-thermal simulation framework requires a great many deal of inputs, like the colour converting material's fluorescent and non-fluorescent optical properties and how these change with temperature and optical power. Thus another goal of this doctoral work was focused on developing inverse methods to extract these parameters from experimental measurements of scattering and fluorescent samples. Taking both the inverse method and the simulation framework together, this research provides an important step forward towards developing a comprehensive solution that permits designing novel high-luminance solid-state white light sources that can avoid the current opto-thermal limitations.

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Fiberoptic networks form the backbone for the internet. Altough this form of communication is superior to copper connections in various aspects, the cost remains an issue. External components such as lasers and photodetectors are required to convert data from the electrical domain to the optical domain and back. This project focuses on reducing the cost of the receiving side by integrating the photodetector with the subsequent circuitry in a fully integrated CMOS implementation. Previous research has already yielded promising results, but ultimately, the bottleneck remains the photodetector. In this project research is done to novel photodetectors, which can be integrated in standard CMOS processes.

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In recent years, ultra-wideband (UWB) signal based radar and imaging systems have been investigated for the use in harsh industrial environments. UWB localization can be used for tracking robots, persons, etc. The present work extends the use of UWB in harsh industrial environments to radiation environments. In these environments, robust UWB systems can extend the capabilities of for instance robotics used in radiation environments. Next to the ranging capabilities, UWB imaging can be used to create an image of the surroundings or see through the surface of an non-transparent object.This work focuses on the design of universal CMOS circuits, which can be used in the proposed harsh environments. To estimate the effect of the many applications and different operation conditions, a 1-D transmission line model has been proposed. This model estimates the reflection and transmission parameters of the used electromagnetic (EM) signals for a certain application. These results can then be used to determine the minimal hardware requirements.In order to be able to easily adapt to the changing environment (depending on the application) and to the different regulations, an industrial UWB sensor must be highly adjustable. In the transmitter, a mixer based UWB pulse generator structure is proposed. Here, a baseband pulse will be up-converted to the correct frequency spectrum using a frequency mixer. This allows to decouple the center frequency and spectral width of the UWB pulse, and so allowing for a highly flexible output signal.In a first part of this dissertation, two versions of a UWB baseband pulse generator are presented and designed in 40 nm CMOS. The first chip introduced a triangular wave baseband pulse generator with a pulse width adjustable between 280 ps and 7.5 ns. However, over this entire pulse width tuning range, the pulse amplitude has a 38\% variation. In the second chip, this pulse amplitude variation is minimized by implementing an independent pulse amplitude control loop. This system reduces the amplitude variation to only 13% while still providing a 660 ps to 3.8 ns pulse width tuning range.Next, a novel frequency mixer architecture is proposed in order to compensate the Voltage Controlled Oscillator (VCO) leakage signal at the output of the mixer. The design introduces the use of a replica mixer, which only generates this leakage signal. The replica's output can then be used to compensate the leakage at the output of the original frequency mixer.A second main part of the research focuses on a Radiation Hardened By Design (RHBD) time-accurate data transmitter and receiver design. In the envisaged ranging and imaging systems, the information is embedded in the timing of multiple signals. In harsh environments it may be useful to transfer these signals over a long distance. Here, this is done using signals based on the Low Voltage Differential Signaling (LVDS) / Scalable Low Voltage signaling (SLVS) standard. To enable the use in time accurate systems, both the transmitter and the receiver need to minimize the difference in the rise and fall output delay. Additionally, the jitter of both systems needs to be minimized. Hence, any noise or distortion introduced by this link will decrease the resolution of the entire system. Both the transmitter and receiver are designed in 65 nm CMOS.In the receiver, the propagation delay of the rising and falling output edges are equalized using a replica receiver, measuring this imbalance. This measured imbalance is then used to adjust the slew rate of the output edges. This compensation loop minimizes the variations in the output delays of the rising and falling edges generated by the process, temperature and power supply (PVT) variations and the total ionizing dose (TID) radiation effects. The proposed design only showed a 0.5 ps increase in this imbalance at a TID radiation level of 500 Mrad (= 5 Mgy). This is a 27 times improvement compared to the open loop receiver. Additionally, the effect of the mismatch between the original and replica receiver is analyzed.In the time-accurate data transmitter, the RHBD is mainly focused on the architecture. The proposed design uses a resistor based current driver architecture. Hence, only an imbalance in these resistors will have an effect on the propagation delay. Results showed a low imbalance in the propagation delay of the output edges due to process corners, temperature and power supply variations. Moreover, at a TID level of 500 Mrad (= 5 Mgy), the proposed architecture only shows a 0.55 ps increase in the imbalance between the rise and fall output delays, without the need of adding extra compensation loops. Finally, the proposed design is capable of generating a highly flexible pre-emphasis signal.

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The human visual system has the ability to adapt to the color and intensity of the illumination to ensure object colors remain fairly stable under changing lighting conditions. Although several models, called chromatic adaptation transforms (CAT), exist that attempt to predict the color shift caused by a change in illumination conditions, the models are typically only applicable to simple visual fields - a flat uniform central stimulus surrounded by a flat uniform background and similar surround - lit by (quasi-)neutral illumination. However, it is known from color constancy studies that object and scene realism and complexity play an important role in determining the degree of adaptation and hence object color appearance. In addition, it is also known that light source chromaticity has an impact on the degree of adaptation. However, neither scene complexity, nor light source chromaticity is taken into account by most commonly used CAT models. Neither is it well known how to take adaption to multiple light sources, commonly encountered in real-life situations (e.g. daylight and electric lighting) into account. the project's aim is to increase the understanding and modelling capabilities of chromatic adaptation in more complex viewing conditions -multiple colored illumination sources and spatially complex backgrounds-that can currently be dealt with by existing CATs.

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With the advent of autonomous vehicles, Smart Cities, Industry 4.0 and many more Internet-of-Things related applications, our future society and lives become highly dependent on high-tech electronics. Unfortunately, all high-tech electronics are sensitive to ElectroMagnetic Interference (EMI), while the increasing electrification of, amongst others, vehicles and machines unavoidably means a much harsher electromagnetic environment. In addition, the continuing miniaturization of electronics and decreasing supply voltages makes new electronic products even more vulnerable to EMI. It is therefore of utmost importance to develop the required knowledge and techniques to assure that safety- or mission-critical systems will not suffer from unacceptable risks when being exposed to both intentional and unintentional EM disturbances. This challenge goes well beyond what is needed for compliance to the EMC Directive for CE certification for normal household applications. While for those applications, one malfunction in every 2-3 years might be perfectly acceptable, safety- or mission-related applications with possibly critical consequences might need a mean-time-between-failure of more than SI{100}{} or even SI{10000}{} years! For automotive applications, one even aims at only one dangerous failure in every 1 million years of operation due to the huge number of vehicles on the road.The aim of the study leading to this PhD manuscript was to create techniques and measures to help achieve resilience to EM disturbances in safety- or mission-critical systems. 'Resilience' as used here means that in case of disturbance, the developed techniques and measures should make the system 'real-time fault-tolerant' for EMI so that the system continues to work as intended in a safe manner. In practice, the study for this PhD manuscript focused on hardware-based techniques and measures to minimize the Bit-Error-Rate (BER) within crucial communication channels. This was done by modifying some commonly used techniques from the discipline of Functional Safety, such as redundancy in combination with majority voting, with the appropriate EMC knowledge to make them much more performant to cope with EMI. Within Functional Safety, redundancy is mainly used to cope with random failures. However, EMI is a complex phenomenon which has to be seen as a systematic, common cause failure. Indeed, 'systematic' because a given system design in a given digital state will always behave in the same way when a given EM disturbance is applied. 'Common cause' because EMI influences many different components at the same time. A typical redundant system is to have two or more identical sets of hardware and software with the same inputs, and performing the same operations on them. When a malfunction occurs in one of these 'parallel channels', a comparator/voter detects that their outputs no longer agree and triggers appropriate actions to maintain safety. Unfortunately, the malfunctions that EMI creates in identical channels can easily be so similar that the comparator/voter cannot tell that there is a problem at all. In this PhD manuscript, several ways are presented to achieve that the parallel paths in a redundant system exhibit a different behaviour ('EM-diversity') when subjected to the same EMI.To validate the performance of the proposed EM-diversity techniques, an efficient simulation framework is used. This simulation framework allows to apply a large variation of EMI disturbances (incoming fields, transient disturbances, ESD, etc.) to (simplified) models of safety-critical systems. The post-processing integrates statistical analysis to check how electromagnetic disturbances affect e.g. the BER. Thanks to this, the effectiveness of different types of diverse redundancy (inversion, spatial, frequency, time, etc.) for various types of EMI can be compared in depth.The first part of this manuscript introduces two types of harsh Electromagnetic (EM) environments, namely a plane wave environment and reverberation environment. The first type can be compared with an open space environment in real life or an anechoic chamber as an EMC test environment. This type of environment subjects the system-under-test only to a single plane wave at a time. The second type of environment can be compared with a real life environment which has a lot of reflections occurring on e.g. as buildings, cars, humans, etc. In the EMC testing, this is mimicked in a reverberation chamber. This type of environment subjects the system-under-test to many plane waves, coming from many random directions, at the same time.The experiments that have to be performed to analyse the EM-diversity properties of the proposed techniques and measures are incorporated in an in-house built simulation framework. This simulation framework is optimised for efficiency and applicability. The effect of the two EM environments is modelled by a limited set of full-wave simulations of the geometry under consideration. The results from that simulation are implemented in the framework and the effect of the disturbances is calculated by using an efficiently implemented reciprocity-based technique. In addition, all properties of the encoding and decoding methods for the data which is communicated over the subjected geometry can be modified efficiently. By using sets of random data and varying the parameters within the model using a Monte-Carlo method, statistically relevant metrics are achieved and can be used to compare the effectiveness of the introduced techniques and measures (T&Ms) to create EM-resilience. The metrics comprises the BER and the number of false negatives or undetectable errors.In this PhD manuscript, several new hardware EM-diverse T&Ms are introduced. These T&Ms are based on several properties of the hardware that can be changed. First, the possibility of matching or not matching the impedances of micro-strips is investigated on redundant and non-redundant geometries. Next, the use of an extra communication channel with inverted data is used to see if it could introduce EM-diverse behaviour. Furthermore, using three micro-strips in different orientations to create spatial diversity is investigated and effectively creates EM-diverse systems. Two final methods which change the timing of the data going over the communication channels is analysed. The transmission start time is changed to create time diversity and the transmission data rate is changed to create frequency diversity. Both methods show that they effectively introduce EM-diverse properties to the system, each with their own specific properties.In addition, this manuscript studies the use of a matched filter as a possible measure to create EM-resilience. The matched filter is a well-known digital processing technique in receivers to maximise the signal-to-noise ratio. This technique was never before investigated in the light of EM-resilience. Additionally, the matched filter method is compared with a majority voter. It is shown that using a matched filter could even be more effective than using a majority voter under some condition.The last part of this manuscript compares the proposed techniques in several ways and concludes which type of diversity to create EM resilience can be used in which situation. The comparison is based on the two main metrics used in this manuscript, namely the BER and the number of false-negatives or undetectable errors when using redundancy.