The Complementary Metal-Oxide-Semiconductor (CMOS) industry has seen tremendous developments over the past several decades and state-of-the-art fabrication technology has likewise been developed. This fabrication technology develops Photonic Integrate Circuits (PIC) which can guide, split, and modulate photonic waves within a small chip scale. On-chip optical phased arrayed waveguides that operate at high power overcome the current limitations of some conventional applications. This paper discusses two applications of on-chip optical waveguide systems: optical phased array (OPA)-based Light Detection and Range (LiDAR) and waveguide array Dielectric Laser Accelerator (DLA). Both the LiDAR and DLA structures require similar properties to achieve optimized performance. These properties are as follows: capability to handle high power, the ability to split the high power evenly through several waveguide branches and distribute the same degree of optical phase on each branch at specific spatial locations, efficient designs of active phase-tuning structures, and the ability to re-combine several waveguide branches into the sub-wavelength pitch spacing array without crosstalk. Additionally, both structures must resolve specific fabrication challenges on each waveguide component. To address these issues, this paper discusses the theoretical reviews of OPA, the Laser-Induced Damage Threshold (LIDT) of optical waveguide materials, and techniques to reduce crosstalk in sub-wavelength pitch size arrays, such as extreme skin-depth (e-skid) waveguides and propagation constant mismatched waveguides. We propose optimized designs for both OPA-based LiDAR and waveguide array DLA with passive and active devices, respectively, and explain the optimized parameters and its simulation results for each component from the full layout of devices. Furthermore, we discuss the fabrication process of the devices and show the resolutions of fabrication challenges, such as trapping void gaps in an e-skid array structure, writing errors of electron beam lithography of large dense patterns, and silicon nitride to silicon hybrid waveguide pattern alignments. Next, we show the experimental setups and the measurement results from the fabricated OPA devices and analyze the results. Finally, this paper concludes the research of the proposed devices and proposes more designs for both OPA-based LiDAR and waveguide arrayed DLA structures that can further increase increase its performance.<br>

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<div>Increasing flexibility of light manipulation is vital for various domains including both biomedical and military applications, where a lack of photon control could become critical. The efforts conducted and projected within this proposal are focused on three major areas: semi-continuous planar thin film photomodification for infrared (IR) filtering, nanosphere core-shell structures for obscurance, and all-dielectric sub-wavelength focal lenses for advanced IR sensing.Through a collaborative effort with the Army Research Office, we advanced the tunability of planar plasmonic filters with cutoff wavelengths in the 10–16μm range with photomodification using a 10.6μm CO2laser. Surface-enhanced molecular absorption in concert with three-dimensional (3D) Au nano-structures with inherent broad absorption in the IR band was a novel approach utilized to create such planar filters.Expanding on these, efforts and the results of the 2-dimensional (2D) semicontinuous Au plasmonic planar filtering, we further advanced our research with 3D Au nano-coreshell structures to enable levitated long-wavelength pass filter obscurants. We exploited the radiative effects of Au nano-structures that mimic conventional apertures or antennas, though these structures are on the nanometer scale and demonstrated the filtering characteristics through flow cell.In parallel with our plasmonic filtering we designed, manufactured and tested low loss dielectric microlenses for IR radiation based on a dielectric metasurface layer by patterning a SI substrate and etching to sub-micron depths. For a proof-of-concept lens demonstration,we chose a fine patterned array of nano-pillars with variable diameters.Merging our plasmonic filtering and dielectric microlens efforts, we created a holographic lenslet by designing and simulating a low loss focusing metasurface lens with engineered nano-scaled features to converge off-axis IR radiation. An array of nano-pillars with varied diameter and fixed height and periodicity was chosen for ease of fabrication with single layer etching</div>