Quantum information and quantum computation are linked by a common mathematical and physical framework of quantum mechanics. The manipulation of the predicted dynamics and its optimization is known as quantum control. Many techniques, originating in the study of nuclear magnetic resonance, have found common usage in methods for processing quantum information and steering physical systems into desired states. This thesis expands on these techniques, with careful attention to the regime where competing effects in the dynamics are present, and no semi-classical picture exists where one effect dominates over the others. That is, the transition between the diabatic and adiabatic error regimes is examined, with the use of such techniques as time-dependent diagonalization, interaction frames, average-Hamiltonian expansion, and numerical optimization with multiple time-dependences. The results are applied specifically to superconducting systems, but are general and improve on existing methods with regard to selectivity and crosstalk problems, filtering of modulation of resonance between qubits, leakage to non-compuational states, multi-photon virtual transitions, and the strong driving limit.

The utilization of micro-scale technologies is limited by the speed of their manufacture. Micro-milling is one particular technology used to manufacture micro-scale parts which could benefit extensively from an increase in throughput. Micro-milling involves a rotating cutter slightly thicker than a human hair removing material while spinning at speeds often over one hundred thousand revolutions per minute. An obvious solution to the throughput bottleneck is to move current micro-mills faster using existing technology; however, simply increasing the operational speed of existing micro-mills will lead to vibration and trajectory following problems. If a micro-mill cannot be positioned precisely, then part tolerances cannot be maintained. Thus any increase in throughput would be counterproductive in terms of overall performance. This dissertation presents techniques to improve the performance of micro-mills, as well as other flexible machines. Theses improvements are possible through the utilization of the vibration suppression scheme of input shaping. By thoughtfully altering the commands sent to flexible systems, their vibration can be significantly reduced. Input shaping was effectively applied to an existing micro-mill, which improved part tolerances and increased operational speed. However, at extremely high speeds, traditional input shaping is not effective at following complicated trajectories. Therefore, new input shaping techniques were developed specifically for trajectory tracking of extremely fast motions on micro-mills and other flexible systems. Often machines cannot achieve these high speeds while maintaining their accuracy because of the mechanical design of the machines themselves. If the mechanical design of micro-mills and other machines consider flexible and lightweight design alternatives that utilize input shaping for vibration suppression instead of stiff and heavy designs, then faster machine motion will be possible. By considering input shaped flexible systems as part of traditional mechanical design processes, these flexible solutions allow vast performance improvement. Specifically, embodiment design can be improved through consideration of input shaping performance requirements. Through these advancements, this dissertation improves the design, control, and performance of micro-mills and other flexible machines.

Command Generation has been shown to be a practical and effective control scheme for eliminating payload swing on industrial cranes. However, this technology has not been used to its full potential. One reason is that nonlinear crane dynamics degrade the performance of current command generators, making them challenging to use. A second reason is that few crane operators are aware of this technology. Therefore, this thesis strives to alleviate these problems through the completion of three major tasks. First, new command generation algorithms are developed that compensate for nonlinear crane dynamics. Two major sources of non-linear dynamics are targeted: nonlinear drive dynamics, and non-linear physical dynamics of tower cranes. Second, command generation are examined from an educational perspective; both in the classroom and in the working field. Third, three experimental crane devices were built to fulfill the two prior tasks.

Genetic algorithm is often used to find the global optimum in a multi-dimensional search problem. Inspired by the natural evolution process, this algorithm employs three reproduction strategies -- cloning, crossover and mutation -- combined with selection, to improve the population as the evolution progresses from generation to generation. Femtosecond laser pulse tailoring, with the use of a pulse shaper, has become an important technology which enables applications in femtochemistry, micromachining and surgery, nonlinear microscopy, and telecommunications. Since a particular pulse shape corresponds to a point in a highly-dimensional parameter space, genetic algorithm is a popular technique for optimal pulse shape control in femtosecond laser experiments. We use genetic algorithm to optimize third harmonic generation (THG), and investigate various pulse shaper options. We test our setup by running the experiment with varied initial conditions and study factors that affect convergence of the algorithm to the optimal pulse shape. Our next step is to use the same setup to control coherent anti-Stocks Raman scattering. The results show that the THG signal has been enhanced.

The design of a low distortion and high efficiency self-oscillating power amplifier is presented. It is designed using TSMC 0.35µm, 2p4m CMOS technology. We use noise shaping to reduce the THD (Total Harmonic Distortion). This design can be applied to hearing aids. The supply voltage is 1.5V for hearing aids. Experimental results demonstrate that the proposed amplifier has the total harmonic distortion (THD) of 0.0751% and power efficiency around 90.1%. Measurement result reveals that this circuit can be up to 0.25% of the THD and 89.7% of the power efficiency. This result shows that the proposed power amplifier has superior performance in THD and power efficiency, and this circuit is applicable to low-distortion, high-efficiency, and low-voltage applications, such as the hearing aids.

This thesis presents a Mixed Linear/Switching Control (MLSC) scheme for voltage regulator modules (VRM). The MLSC employs two loops of feedback compensation, inner-loop switching compensation and outer-loop linear regulation. The purpose of the switching compensation is to linearize and stabilize the buck converter under the influence of switching noise and load variation. With switching compensation, the linearized plant of the buck converter can be simplified to a first-order stable transfer function at low frequencies. Accordingly, the outer-loop linear controller can be easily designed to regulate the output voltage using the linear control theory. The advantage of the proposed MLSC scheme is two-fold: easy to design and of low circuit complexity. There is no need of using any current detecting resistor and PWM generator, and also the stability and performance can be easily met by choosing positive controller coefficients. A 12V/1V single-phase VRM with proposed control is designed and simulated, which shows an output regulation with 0.4% steady- state output error and 7% load regulation error in response to the load current steps from 60A/1A to 1A/60A, at a slew rate of 60A/µsec.

This thesis utilized pulse shaping technology to study chirp response of SSBR and attempt to analyze contribution of SSBR in mode-locked process. A home-made pulse shaping system (based on 4f scheme) with Freezing algorithm and Gerchberg-Saton algorithm was demonstrated. A normal dispersion at nonabsorbable wavelength and an anomalous dispersion around absorbable wavelength region in SSBR were obtained. Meanwhile, a Kramers-Kronig relation like behavior of pulse depression/broadening ratio in the strained multiple quantum well was observed and also refer to that pulse starting force is stronger at short wavelength. Decrease of pulse compression with increasing power of negative chirp incident pulse was characterized. Unclear power dependence for positive chirp case was also performed. These could be due to competition of band-filling and pump dump process. In addition, higher reflectivity and tendency of lower saturation fluence of SSBR for negative chirp incident pulse were observed.

This thesis mainly proposes a new method to design Hinf Loop Shaping Robust Controller by choosing Weighting Function. In the paper, the author first introduces the concept of SISO Loop Shaping design. It utilizes Small Gain Theorem to achieve robust stability of the system and develops the relationship of Open Loop Transfer Function(L) to Robust Performance and to Robust Stability of the system.. These concepts can be extended to Hinf Loop Shaping method. As to Hinf loop shaping method, the author first introduces the problem of Robust Stability under the framework of Coprime Factor and the theory of Hinf Loop Shaping, and then discusses the relationship between stability margin and the different pole-zero system. Generally speaking, the control theories of the Loop Shaping are mainly used for making appropriate adjustments between the stability and performance of the system. Because the system can conform to the performance requirement through the choice of Weighting Function, the author proposes a new method toward MIMO system to design Hinf Loop Shaping Controller by choosing Weighting Function under the framework of Hinf Loop Shaping. Moreover, at the end of the paper,the author compares the result of the new method with that of the literature.

<p>Orthogonal Frequency Division Multiplexing (OFDM) is well known as an efficient technology for wireless communications and is widely used in many of the current and upcoming wireless and wireline communication standards. However, it has some intrinsic drawbacks, e.g., sensitivity to the inter-carrier interference (ICI) and high peak-to-average power ratio (PAPR). Additionally, the cyclic prefix (CP) is not spectrum efficient and fails when the channel delay spread exceeds the length of CP, which will result in inter-symbol interference (ISI). In order to combat or alleviate these drawbacks various techniques have been proposed, which can be categorised into two main classes: techniques that keep the structure of OFDM and meanwhile increase the system robustness or re-organise the symbol streams on each sub-carrier, and techniques that increase the ISI/ICI immunity by adopting well designed pulse shapes and/or resorting to general system lattices. The latter class are coined as Generalised FDM (GFDM) throughout this thesis to distinguish with the former class.</p><p>To enable seamless handover and efficient usage of spectrum and energy, GFDM is expected to dynamically adopt pulse shapes that are optimal in doubly (time and frequency) dispersive fading channels. This is however not an easy task as the method of optimal pulse shape adaptation is still unclear, let alone efficient implementationmethods. Besides, performance of GFDM highly depends on the channel estimation quality, which is not straightforward in GFDM systems.</p><p>This thesis addresses, among many other aspects of GFDM systems, measures of the time frequency localisation (TFL) property, pulse shape adaptation strategy, performance evaluation and channel estimation.  We first provide a comparative study of state-of-the-art GFDM technologies and a brief overview of the TFL functions and parameters which will be used frequently in later analysis and discussion. A framework for GFDM pulse shape optimisation is formulated targeting at minimising the combined ISI/ICI over doubly dispersive channels. We also propose a practical adaptation strategy utilising the extended Gaussian functions (EGF) and discuss the trade-off between performance and complexity.  One realisation under the umbrella of GFDM, namely OFDM/OQAM, is intensively studied and an efficient implementation method by direct discretisation of the continuous time model has been proposed.  Besides, a theoretical framework for a novel preamble-based channel estimation method has been presented and a new preamble sequence with higher gain is identified. Under the framework, an optimal pulse shape dependent preamble structure together with a suboptimal but pulse shape independent preamble structure have been proposed and evaluated in the context of OFDM/OQAM.</p>

The Nyquist WDM system realizes a terabit high spectral efficiency transmission system by allocating several subcarriers close to or equal to the baud rate. This system achieves optimal performance by maintaining both temporal and spectral orthogonality. However, ISI and ICI effects are inevitable in practical Nyquist WDM implementations due to the imperfect channel response and tight channel spacing and may cause significant performance degradations. Our primary research goals are to combat the ISI effects via the transmitter digital pre-shaping and to remove the ICI impairments at the receiver using MIMO signal processing. First we propose two novel blind channel estimation techniques that enable the transmitter pre-shaping design for the ISI effects mitigation. Both numerical and experimental results demonstrate that the two methods are very effective in compensating the narrow band filtering and are very robust to channel estimation noise. Besides pre-shaping, the DAC-enabled transmitter chromatic dispersion compensation is also demonstrated in a system with high LO laser linewidth. Next a novel “super-receiver” structure is proposed, where different subchannels are synchronously sampled, and the baseband signals from three adjacent subchannels are processed jointly to remove ICI penalty. Three different ICI compensation methods are introduced and their performances compared. The important pre-processes that enable a successful ICI compensation are also elaborated. Despite ICI compensation, the joint carrier phase recovery based on the Viterbi-Viterbi algorithm is also studied in the carrier phase locked systems. In-band crosstalk arises from the imperfect switch elements in the add-drop process of ROADM-enabled DWDM systems and may cause significant performance degradation. Our third research topic is to demonstrate a systematic way to analyze and predict the in-band crosstalk-induced penalty. In this work, we propose a novel crosstalk-to-ASE noise weighting factor that can be combined with the weighted crosstalk weighting metric to incorporate the in-band crosstalk noise into the Gaussian noise model for performance prediction and analysis. With the aid of the Gaussian noise model, the in-band crosstalk-induced nonlinear noise is also studied. Both simulations and experiments are used to validate the proposed methods.