This dissertation addresses three research challenges in planar lightwave circuit (PLC) optical signal processing. 1. Dynamic localization, a relatively new class of quantum phenomena, has not been demonstrated in any system to date. To address this challenge, the quantum system was mapped to the optical domain using a set of curved, coupled PLC waveguides in aluminum gallium arsenide (AlGaAs). The devices demonstrated, for the first time, exact dynamic localization in any system. These experiments motivate further mappings of quantum phenomena in the optical domain, leading toward the design of novel optical signal processing devices using these quantum-analog effects. 2. The PLC microresonator promises to reduce PLC device size and increase optical signal processing functionality. Microresonators in a parallel cascaded configuration, called "side coupled integrated spaced sequence of resonators" (SCISSORs), could offer very interesting dispersion compensation abilities, if a sufficient number of rings is present to produce fully formed "Bragg" gaps. To date, a SCISSOR with only three rings has been reported in a high-index material system. In this work, one, two, four and eight-ring SCISSORs were fabricated in AlGaAs. The eight-ring SCISSOR succeeded in producing fully formed Bragg peaks, and offers a platform to study interesting linear and nonlinear phenomena such as dispersion compensators and gap solitons. 3. PLCs are ideal candidates to satisfy the projected performance requirements of future microchip interconnects. In addition to data routing, these PLCs must provide over 100-bit switchable delays operating at ~ 1 Tbit/s. To date, no low loss optical device has met these requirements. To address this challenge, an ultrafast, low loss, switchable optically controllable delay line was fabricated in AlGaAs, capable of delaying 126 bits, with a bit-period of 1.5 ps. This successful demonstrator offers a practical solution for the incorporation of optics with microelectronics systems. The three aforementioned projects all employ, in their unique way, the coupling of light between PLC waveguides in AlGaAs. This central theme is explored in this dissertation in both its two- and multi-waveguide embodiments.

This dissertation addresses three research challenges in planar lightwave circuit (PLC) optical signal processing. 1. Dynamic localization, a relatively new class of quantum phenomena, has not been demonstrated in any system to date. To address this challenge, the quantum system was mapped to the optical domain using a set of curved, coupled PLC waveguides in aluminum gallium arsenide (AlGaAs). The devices demonstrated, for the first time, exact dynamic localization in any system. These experiments motivate further mappings of quantum phenomena in the optical domain, leading toward the design of novel optical signal processing devices using these quantum-analog effects. 2. The PLC microresonator promises to reduce PLC device size and increase optical signal processing functionality. Microresonators in a parallel cascaded configuration, called "side coupled integrated spaced sequence of resonators" (SCISSORs), could offer very interesting dispersion compensation abilities, if a sufficient number of rings is present to produce fully formed "Bragg" gaps. To date, a SCISSOR with only three rings has been reported in a high-index material system. In this work, one, two, four and eight-ring SCISSORs were fabricated in AlGaAs. The eight-ring SCISSOR succeeded in producing fully formed Bragg peaks, and offers a platform to study interesting linear and nonlinear phenomena such as dispersion compensators and gap solitons. 3. PLCs are ideal candidates to satisfy the projected performance requirements of future microchip interconnects. In addition to data routing, these PLCs must provide over 100-bit switchable delays operating at ~ 1 Tbit/s. To date, no low loss optical device has met these requirements. To address this challenge, an ultrafast, low loss, switchable optically controllable delay line was fabricated in AlGaAs, capable of delaying 126 bits, with a bit-period of 1.5 ps. This successful demonstrator offers a practical solution for the incorporation of optics with microelectronics systems. The three aforementioned projects all employ, in their unique way, the coupling of light between PLC waveguides in AlGaAs. This central theme is explored in this dissertation in both its two- and multi-waveguide embodiments.

In this thesis, miniaturized wavelength interrogators based on planar lightwave circuits (PLCs) are investigated and developed for the optical fiber sensing applications in the aircraft structural health monitoring (SHM) and optofluidic analysis. Two interrogation systems based on an arrayed waveguide grating (AWG) and an Echelle diffractive grating (EDG) are developed and used to convert the optical sensing signals into strain, temperature, vibration, damage, and humidity information for the aircraft SHM. A fiber Bragg grating (FBG) sensing system using developed interrogators is then demonstrated in a field test for aircraft SHM applications. For optofluidic analysis, a PLCs based optofluidic device consisting of two on-chip lens sets is built to enhance the optical manipulation capability of particles. Then, a solution to a multi-functional Lab-on-a-Chip platform for optofluidic analysis is proposed, which integrates the developed particle maneuvering device, grating-structured sensors, and miniaturized interrogators.

In this thesis, miniaturized wavelength interrogators based on planar lightwave circuits (PLCs) are investigated and developed for the optical fiber sensing applications in the aircraft structural health monitoring (SHM) and optofluidic analysis. Two interrogation systems based on an arrayed waveguide grating (AWG) and an Echelle diffractive grating (EDG) are developed and used to convert the optical sensing signals into strain, temperature, vibration, damage, and humidity information for the aircraft SHM. A fiber Bragg grating (FBG) sensing system using developed interrogators is then demonstrated in a field test for aircraft SHM applications. For optofluidic analysis, a PLCs based optofluidic device consisting of two on-chip lens sets is built to enhance the optical manipulation capability of particles. Then, a solution to a multi-functional Lab-on-a-Chip platform for optofluidic analysis is proposed, which integrates the developed particle maneuvering device, grating-structured sensors, and miniaturized interrogators.

The last two decades have witnessed a large increase in capacity in telecommunication systems, thanks to the development of high bandwidth, fiber optic based networks. Nevertheless the continuing growth of Internet data traffic, fuelled by the development of numerous services like on-line commerce, video on demand, large audio/video files downloads, demands for a significant increase in the ability of the network nodes to manage incoming and outcoming data streams effectively and fast. The different functionalities that are needed include add/drop channel multiplexing, routing, signal reshaping and retiming, electrical/optical and optical/electrical conversion. This has stimulated a large effort towards the investigation of technologies for opto-electronic integration at a wafer level, in order to cope with all the required operations, while limiting overall costs. Among the different approaches proposed, one of the most promising is the “Silicon optical bench”, which relies on the well established VLSI technology for the microelectronics part and on planar lightwave circuits (PLCs) made either with silica-on-silicon waveguide technology (low index contrast) of amorphous silicon technology (high index contrast) on the integrated optics side. This thesis presents the development of new techniques and methodologies utilized in photonic device fabrication, which can be used to facilitate integration of temperature sensitive elements. The process is based on low temperature, plasma assisted, thick film deposition. First, a low temperature (300°C) deposition process based on Plasma assisted Chemical Vapour Deposition (PACVD) for the fabrication of silica based Planar Lightwave Circuits (PLC) is developed. The low thermal budget lends itself to monolithic integration with devices fabricated with different technologies. Absorption bands at around the wavelengths 1.48µm and 1.51µm caused by N-H and Si-H bonds within the material, respectively, had previously been thought to be intrinsic to the PACVD deposition method, when using N2O as oxidant gas of SiH4 and the other dopant precursors. The traditional method to eliminate these absorption bands was high temperature (>1000°C) annealing that seriously hinders device integration. An important achievement in this thesis is the improved suppression of these two absorption bands while keeping the whole fabrication temperature below 300°C and also having a high deposition rate. A complete fabrication process for silica planar lightwave circuits was also developed, by optimising the photolithography and etching step. Finally the effect of dopants like Ge and B on the optical properties of the deposited silica glass was investigated, with particular emphasis to the photosensitive properties of the material upon illumination in the near UV. UV trimming is shown to be a versatile method to selectively control polarization birefringence of devices. Transmission dips of above 50dB were achieved in photo-induced gratings in low temperature deposited B-Ge codoped waveguide cores, without the need for hydrogen loading or other sensitisation techniques. The application of a high refractive index like amorphous silicon is addressed for the realization of efficient Bragg reflectors, either as vertical cavity laser mirrors or as dispersive element for planar waveguides used in highly selective co-directional coupler filters. Applications of amorphous silicon as core material for photonic crystal devices are also shown. The investigations carried out in this thesis show that PACVD technology can provide low-loss and UV sensitive material suitable for realizing a variety of low cost integrated devices for future all optical networks. / QC 20101004