A technological platform based on low-temperature hybrid sol-gel method for fabrication of optical waveguides and integrated optical components has been developed. The developed chemistry for doping incorporation in the host network provides a range of refractive indexes (1.444-1.51) critical for device optimization. A passivation method for improving long-term stability of organic-inorganic sol-gel material is reported. The degradation of waveguide loss over time due to moisture adsorption from the atmosphere is drastically suppressed by coating the material with a protective thin SiO2 film. The results indicate a long-term optical loss below 0.3 dB/cm for protected waveguides. The theory of multimode interference couplers employing self-imaging effect is described. A novel approach for design of high-performance MMI devices in low-contrast material is proposed. The design method is based on optimization of refractive index contrast and width of a multimode waveguide (the body of MMI couplers) to achieve a maximum number of constructively interfering modes resulting to the best self-imaging. This optimization is carried out using 3D BPM simulations. This method was applied to design 1 x 4, 1 x 12, and 4 x 4 MMI couplers and led to a superior performance in excess loss, power imbalance in output ports, and polarization sensitivity. Taking advantage of the inherent input-output phase relations in a 4 x 4 MMI coupler, an optical 90° hybrid is realized by incorporation a Y-junction to coherently excite two ports of the coupler. A series of MMI couplers were fabricated and characterized. The experimental results are in good agreement with the design. Measured performance of the sol-gel derived MMI components was compared to analogues fabricated by other technologies. The comparison demonstrates the superior performance of the sol-gel devices. The polarization sensitivity of all fabricated couplers is below 0.05 dB.

Due to the properties of extremely high quality factor and small mode volume, microsphere resonators have attracted considerable attention for signal processing, fiber communication and photon computation applications. This research work studies the optical properties of microsphere amplifier and laser. The Er³⁺-doped tellurite glass was examined, including emission cross-section, absorption cross-section and lifetime analysis. McCumber and Judd-Ofelt theories were used for theoretical calculations. Whispering gallery modes in the microsphere were calculated by using the measured parameters. Signal enhancement was obtained in this Er³⁺-doped tellurite glass microsphere. The enhancement of this Er³⁺-doped tellurite glass microsphere exceeds 12dB. Besides, the mode in a single mode tapered fiber was analyzed. Theoretical analysis was also performed to optimize the coupling scheme. We also analyzed the lasing characteristics of microsphere laser, including threshold, lasing wavelength, output power optimization, and temperature dependence. Theoretical calculations for these properties were also presented. State-of-the-art L-band microsphere laser with maximum output power of 124.5 μW was demonstrated which has potential in various photonic applications.

There are several primary factors that limit the data capacity of a volumetric bit-wise optical data storage system. Firstly, the data density in each layer is limited by the spot size formed at the focus of the objective lens. The spherical aberration induced by the medium also limits the maximum depth that an optical system can reach with diffraction limited focus. A second primary factor is the undesired detection of data from layers other than the layer at the laser focus, which is an effect called inter-layer crosstalk. In the last, the transmission and the reflection rate of the medium sets the limit of the number of the data layers for a given laser diode. In the modeling, the inter-layer crosstalk of volumetric bit-wise storage systems is simulated by using three methods. Several far-field and near-field systems with spherical aberration compensators are presented. In addition, the maximum surface densities of these systems are discussed. A dynamic test stand equipped with a tracking servo is built for testing the fluorescent material performance in a simulated space environment. Coupon samples made of Super-Rens material are tested in another dynamic test stand equipped with a focus servo. Controls of writing conditions for Super-Rens material are investigated with respect to the focus spot speed and data rate. Overall, this dissertation provides a description of volumetric bit-wise optical data storage technology, in terms of the system and material aspects, through simulation and experiments.

This work investigates complete Mueller matrix polarization signatures in scattered light. A number of samples are studied using Mueller matrix imaging polarimetry, where samples are actively illuminated with a sequence of known polarization states. The capabilities of the Mueller matrix imaging polarimeter for scatter measurements are explored. Measuring polarization properties in scattered light from targets is important in remote sensing because polarization offers additional information unavailable from intensity measurements alone. Polarization helps discriminate surface features or material properties. The Mueller matrix contains detailed polarization and depolarization information possible for scattering objects, and every Mueller element conveys polarization coupling information. Polarization signatures are obtained at a number of different illumination and scatter angles, and a Mueller matrix bidirectional reflectance distribution function (MBRDF) in one dimension is used to compare various targets. Polarization metrics including diattenuation, retardance, and depolarization obtained from Mueller matrix data images provide methods for comparison, classification, and discrimination of targets. This work examines these reduced polarization parameters and how they vary as a function of scattering geometry, in order to determine which polarization signatures are the best discriminants for remote sensing or metrology. The Mueller matrix bidirectional reflectance distribution function, diattenuation, retardance, and depolarization properties are studied for a diverse group of manmade samples. A group of leaf samples is also studied, to see how natural samples behave and to compare natural and manmade samples. The most prevalent and useful discriminants for scattering samples appear in the depolarization data. Although this is not unexpected, these depolarization properties have not been studied in detail before and are not well described in the literature. Most depolarizing samples investigated showed an inverted Gaussian profile of depolarization magnitude versus scatter angle, with minimum depolarization for specular reflection which increases asymptotically as the scatter angle changes. Other patterns are found in the more noisy diattenuation and retardance data.

On the technical platform of hybrid organic-inorganic sol-gel, the integrated optoelectronics in the forms of heterogeneous integration between the hybrid sol-gel waveguide and the high refractive index semiconductors and the nonlinear functional doping of disperse red chromophore into hybrid sol-gel is developed. The structure of hybrid sol-gel waveguide on high index semiconductor substrate is designed with BPM-CAD software. A hybrid sol-gel based on MAPTMS and TEOS suitable for lower cladding for the waveguide is developed. The multi-layer hybrid sol-gel waveguide with good mode confinement and low polarization dependence is fabricated on Si and InP. As proof of concept, a 1 x 12 beam splitter based on multimode interference is fabricated on silicon substrate. The device shows excess loss below 0.65 dB and imbalance below 0.28 dB for both TE and TM polarization. A nonlinear active hybrid sol-gel doped with disperse red 13 has been developed by simple co-solvent method. It permits high loading concentration and has low optical loss at 1550 nm. The second-order nonlinear property of the active sol-gel is induced with corona poling and studied with second harmonic generation. A 3-fold of enhancement in the poling efficiency is achieved by blue light assisted corona poling. The chromophore alignment stability is improved by reducing the free volume of the formed inorganic network from the sol-gel condensation reaction. An active sol-gel channel waveguide has been fabricated using active and passive hybrid sol-gel materials by only photopatterning and spin-coating. An amplitude modulator based on the active sol-gel containing 30 wt.% of DR13 shows an electro-optic coefficient of 14 pm/V at 1550 nm and stable operation within the observation time of 24 days.

Short, high intensity laser pulses induce nonlinear optical effects in the atmosphere that have the potential to make them propagate for long distances. Applications for long distance propagation of short pulses include active spectral remote sensing and laser lightning control. Much of the work in this field has been done with infrared pulses; however, it has been proposed that ultraviolet pulses have the advantage that longer pulse lengths can be used, thereby delivering more energy. Long pulse lengths lead to a simplified instantaneous model for the plasma response, which has been shown by Schwarz and Diels to admit steady state or oscillatory solutions corresponding to beam propagation. We have verified this model and have adjusted it to achieve closer agreement with numerical results. In this work we investigate the effects of transient behavior, and the stability of these solutions. Analysis of the modulational instability is done from the plane wave level to a full three dimensional model of the propagation. It is shown that both the transient behavior arising from the finite pulse length, and the modulational instability cause pulses to fragment over lengths on the scale of meters. We present results showing the growth of unstable modes in various propagation regimes. We discuss the pertinent length scales for ultraviolet pulses, as well as the impact of the instability and transient effects on theory and experiment. The results imply that continuous-wave models are very limited when used to predict dynamical properties of pulse propagation.

Manufacturers of optical glass strive to make a product that is homogeneous, isotropic, and free of any bubbles or mechanical strain. Glass used in forming images is very good, but the process of mixing the constituent materials, and melting them into a glass is limited. The index of refraction varies based on the lack of uniformity remaining after the manufacturing process. Transmitted wavefronts will have errors due to this inhomogeneity. The most common method currently used to quantify the homogeneity of a glass sample is to measure in one direction through the glass. Variations along the test axis are integrated resulting in loss of positional information in this direction. Homogeneity is then reported by using the peak-to-valley wavefront error reducing the three dimensional nature of glass to a single value. Not only have we lost the longitudinal information, but we have also lost any knowledge of the transverse texture of the sample. We present in this research a method for retrieving three dimensional information about the inhomogeneity of a glass test piece. Computed tomography provides a well developed methodology for constructing a three dimensional measurement from two dimensional data. Common interferometric measurements, or projections, taken at multiple angles has sufficient information to estimate the full three dimensional structure of the test piece. Important differences from computed tomography used for medical diagnoses are explored. Refraction at the interfaces of the sample limits the number of angles over which projections can be made. The angular distance between projections also influences the accuracy of the reconstructed object.

Scanning Probe Microscopy (SPM) has been proven to be a powerful tool for imaging and lithography with nanometer resolution. The application of SPM to data storage may produce aerial storage densities far greater than what is currently available. As an effort in this direction, the properties of reversible transitions on the molecular scale in a complex of 3-nitrobenzal malononitrile and 1,4-phenylenediamine have been studied, by application of local electric field pulses from a SPM probe. Current pulses injection during the operation of a conducting-tip tapping-mode atomic force microscope has also been developed. Combination of these two techniques should be of importance for MEMS-based data storage. Another effort of ours is to develop an experimental configuration by combining the analytical power of Raman spectroscopy with the nanometer resolution of atomic force microscopy (AFM). Here, an AFM silicon nitride probe, coated with a 40 nm silver layer, was used to significantly enhance the Raman signal by laser excitation of surface plasmons in the tip coating. Experimental results indicate a local surface enhanced Raman scattering (SERS) increase of 105. Lateral scanning of the sample and collecting the SERS signal allows for a 2D image of the chemical identity of the probed sample simultaneous with its topography as measured by the AFM. Also, the ratio of Stokes to anti-Stokes can be used to obtain an absolute map of the local temperature across the sample.

Photonic devices fabricated by ion exchange in glass have evolved to the point where conventional assumptions of waveguide symmetry and mutual independence are no longer valid. For example, during field-assisted ion exchange processes, the nonhomogeneity of ionic conductivity in the vicinity of the waveguide results in a time-dependent perturbation of the electric field. Previous studies have shown that the depth and vertical symmetry of buried waveguides are noticeably affected by the field perturbation. This Dissertation describes an advanced modeling tool for guided-wave devices based on ion-exchanged glass waveguides. A genetic algorithm is proposed to determine the physical parameters that drive the ion exchange process. The diffusion equation describing binary ion exchange is solved numerically. The effect of field perturbation, due not only to the conductivity profile, but also to the proximity of adjacent waveguides or partial masking during a field-assisted burial, is accounted for. A semivectorial finite difference method is then employed to determine the modal properties of the waveguide structures. The model is validated by comparison with a fabricated waveguide containing a Bragg grating. The modeled waveguides are utilized in the design of a multimode interference (MMI) device. A novel genetic algorithm-based design methodology is developed to circumvent issues with the commonly used self-imaging theory that arise when the MMI device operates in the regime of weak guiding. A combination of semivectorial finite difference modeling in two transverse dimensions and mode propagation analysis (MPA) in the propagation direction is used to evaluate the merit of each trial design. Two examples are provided of a 1 x 4 power splitter, which show considerable improvement in power imbalance and polarization dependent loss over that obtained by self-imaging theory.

The writing and reading of 3 level run-length-limited (RLL) modulation signals on optical discs having active (recording) layers comprised of different phase change materials is discussed. These recordings represent a linear storage density enhancement of 50% Vs conventional (2-level) RLL modulation. Thermal simulations of the mark writing process provide a tool that can be used to optimize write strategies for ML-RLL recording.