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This thesis treats the development of an integrated optical sensor array. The sensors are slot-waveguide ring resonators, integrated with on-chip surface grating couplers and light splitters, for alignment tolerant, real-time, refractive index sensing, and label-free biosensing. The work includes: the design of components and system layouts, the development of fabrication methods, the fabrication of sensor chips, the characterization of the chips, and the development of physical system models for accurate extraction of resonance wavelengths in measured spectra. The main scientific achievements include: The evaluation of a novel type of nano-structured optical waveguide for biochemical sensing. The realization of an array of such slot-waveguide sensors, integrated with microfluidic sample handling, for multiplex assays. The first study of the thermal behavior of slot-waveguide sensors and the discovery of unique temperature compensation capabilities. From an application perspective, the use of alignment tolerant surface gratings to couple light into the optical chip enables quick replacement of cartridges in the read-out instrument. Furthermore, the fabrication sequence avoids polishing of individual chips, and thus ensures that the cost benefits of silicon batch micro-fabrication can be leveraged in mass production. The high sensitivity of the slot waveguide resonators, combined with on-chip referencing and physical modeling, yields low limits of detection. The obtained volume refractive index detection limit of 5 × 10−6 refractive index units (RIU), and the surface mass density detection limit of 0.9 pg/mm2, shows that performance comparable to that of commercial non-integrated surface plasmon resonance sensors, made from bulk optical components, canbe achieved in a compact cartridge. / Qc20100715 / SABIO

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In this paper¡Awe use both beam propagation method and BPM_CAD to analysis the characteristics of nonlinear optical waveguide structures. The refractive index of optical waveguide medium changes with field intensity called nonlinear optical waveguide. We use Mode Theory to solve three layers optical waveguide. There are nonlinear cladding, substrate layers and linear film. Not only find the disperson relation curve, but also observe the affections of the input power to field distribution. With the help of this, we propose a general math method to analysis symmetric muti-layer optical waveguide with periodic index that both cladding and substrate are nonlinear. According to the nonlinear dispersion relation we consider both the affections of the input power to refractive index in the film and space soliton at nonlinear interface. We propose a optical coupler and feed-back optical switch. And also, we analysis 2¡Ñ3 branches optical waveguides by changing their media to nonlinear media. According to the result, we find that they have both logic function and optical switch.

In this paper, we used the beam propagation method to analyze the characteristics of nonlinear optical waveguides. Refractive indexes of media in planar optical waveguides are changed with the electric field intensity called nonlinear planar optical waveguides. We use the modal theory to solve the three-layer planar optical waveguide with the guiding film is nonlinear. We not only obtained dispersion relation curves, but also observed the affections of the input power to field distributions. By the basic theory of this, we proposed a novel method to analyze multi-layer planar optical waveguides with nonlinear or localized nonlinear guiding films.By the theory and novel method we pointed out, on the other hand, we proposed an all-optical switch and analyze the all-optical device by the beam propagation method.

The interaction of an evanescent wave and plasmonic nanostructures are simulated in Finite Element Method. Specifically, the optical absorption cross section (Cabs) of a silver nanoparticle (AgNP) and a gold nanoparticle (AuNP) in the presence of metallic (gold) and dielectric (silicon) atomic force microscope (AFM) probes are numerically calculated in COMSOL. The system was illuminated by a transverse magnetic polarized, total internally reflected (TIR) waves or propagating surface plasmon (SP) wave. Both material nanoscale probes localize and enhance the field between the apex of the tip and the particle. Based on the absorption cross section equation the author was able to demonstrate the increment of absorption cross section when the Si tip was brought closer to the AuNP, or when the Si tip apex was made larger. However, the equation was not enough to predict the absorption modification under metallic tips, especially for a AgNP's Cabs; neither it was possible to estimate the optical absorption based on the localized enhanced field caused by a gold tip. With the help of the driven damped harmonic oscillator equation, the Cabs of nanoparticles was explained. In addition, this model was applicable for both TIR and Surface Plasmon Polaritons illuminations. Fitting the numerical absorption data to a driven damped harmonic oscillator (HO) model revealed that the AFM tip modifies both the driving force (F0), consisting of the free carrier charge and the driving field, and the overall damping of the oscillator beta. An increased F0 or a decreased beta will result in an increased Cabs and vice versa. Moreover, these effects of F0 and beta can be complementary or competing, and they combine to either enhance or suppress absorption. Hence, a significantly higher beta with a small increment in F0 will result in an absorption suppression. Therefore, under a Si tip, Cabs of a AuNP is enhanced while Cabs of a AgNP is suppressed. In contrast, a Au tip suppresses the Cabs for both Au and Ag NPs. As an extension of this absorption model, further investigation of the guided mode and a close by nanostructure is proposed, where the scattered wave off the structure attenuates the guided mode with destructive interference.

This thesis deals with the subject of fibre optic magnetic field sensors utilizing iron garnet materials. Such materials exhibit a large Faraday rotation which make them advantageous for application in compact mag­netic field sensors. After an introduction, in which fibre optic sensors and optical methods to measure electric current are reviewed, the original research work is summarized. A system for the measurement of the magneto-optic properties of trans­parent materials is described. Measurement results, showing the influence of temperature, magnetic field direction and sample treatment on the magneto-optical proper­ties of YIG-crystals, are presented. The proper­ties of thin magneto-optical waveguiding films have also been studied using different light coupling methods. Measurement results obtained for holo­graphic grating, prism and edge (end-fire) light coupling to different substituted YIG films are presented. It is shown that the launching method may affect the properties to be measured. The design and performance of several versions of extrinsic guided wave fibre optic magnetic field sensors are then reported. The sensors employ substi­tuted YIG (Yttrium Iron Garnet, Y3Fe5O12) thin film waveguides as sensing elements. Polari­zation maintaining fibres were used as feed and return to provide two signal channels. The signals were combined in a balanced measure­ment system, providing insensitivity to both fluctuations in optical power and loss. Sensors have been made both with separate fibres to guide the light to and from the sensing element and with a single fibre for both functions. The two fibre version, although less ”elegant”, is found to have a better performance. This version also makes it possible to determine both the magnitude and sign of the magnetic field. Measurement results indicate a usable measurement range of at least several mT with a noise equivalent magnetic field level of less than 8 nT/root(Hz). The design and performance of multimode fibre optic magnetic field sensors utilizing the Faraday effect in an epitaxially grown thick (YbTbBi)IG film is also described. This type of sensor is found to be linear over a range from 27 mT to less than 270 nT. Sensor prototypes suitable for current monitoring in high voltage transmission lines have also been developed. / QC 20111209 / YIG

The objective of this research is to investigate the use of laser direct writing to micro-pattern low loss passive optical channel waveguide devices using a new hybrid organic/inorganic polymer. Review of literature shows previous methods of optical waveguide device patterning as well as application of other non-polymer materials. System setup and design of the waveguide components are discussed. Results show that laser direct writing of the hybrid polymer produce single mode interconnects with a loss of less 1dB/cm.

This dissertation outlines the research and development of ground-breaking nanometer sized openings (nanopores) integrated with an on-chip optofluidic platform. This platform represents a significant advancement for single nanoparticle sensing. In this work specifically, the integrated optofluidic platform has been used to electrically and optically filter and detect single nanoparticles using ionic current blockade and fluorescence experiments. The correlation of electrical and optical signal has provided the highest sensitivity single nanoparticle measurements ever taken with integrated optofluidic platforms. The particular optofluidic platform used for this work is an antiresonant reflecting optical waveguide (ARROW). ARROW hollow and solid core waveguides are interference based waveguides that are designed to guide light in low index media such as liquids and gases. Because of this unique guiding property, ARROW hollow cores can be used to sense and analyze low concentrations of single particles. Additionally, because ARROW platforms are based upon standard silicon processing techniques and materials, they are miniature sized (~1 cm2), inexpensive, highly parallelizable, provide a high degree of design flexibility, and can be integrated with many different optical and electrical components and sources. Finally, because of the miniature, integrated nature of the ARROW platform, it has the potential to be incorporated into hand held devices that could provide quick, inexpensive, user-friendly diagnostics. The ARROW platform has been through many revisions in the past several years in an attempt to improve performance and functionality. Specifically, advanced fabrication techniques that have been used to decrease the production time, increase the yield, and improve the optical quality of ARROW platforms are discussed in the first part of this work. These advancements were all developed in order to facilitate the production of high quality integrated nanopores and ARROW platforms. The second part of this work then focuses on the actual integration of micrometer sized openings (micropores) and nanopores in the hollow waveguide section of ARROW platforms for filtering, detecting, and analyzing single nanoparticles. The successes and attempts at achieving these results are the basis of this dissertation of work.

"Photonic crystals have recently been the subject of studies for use in optical signal processing. In particular, a Coupled Resonator Optical Waveguide (CROW) structure has been considered by M. F. Yanik and S. Fan in “Stopping Light All Optically” for use in a time-varying optical system for the storage of light in order to mitigate the effects of waveguide dispersion. In this thesis, the effects of the thermal field on the state stored in such a structure is studied. Through simulation, this thesis finds that when this structure is constructed of gallium arsenide cylinders in air, loss of the signal was found to be caused by free-carrier absorption, and the decay of the signal dominates over thermal spreading of the optical signal’s spectrum."