No description available.

No description available.

No description available.

We have developed a rigorous leaky-mode analysis on the antiresonant reflecting optical waveguides (ARROW¡¦s) using a so-called ¡§coupled electric (CE) coupled magnetic (CH) field method.¡¨ Radiation loss characteristics and the field distribution of the ARROW are analyzed in detail. Meanwhile, both the refractive indices and the thickness dependence for the isolation and distinction of modes are also investigated in this thesis. From the CE¡VCH method, the associated complex symmetric tridiagonal matrices are derived to solve the modal solutions via the eigenvalue-eigenvector technique. The uniquely designed formulation of CE¡VCH method yields better numerical properties, specifically in calculating the field distribution. This is suitable for any combination of materials and is capable of handling complex problems such as the leaky characteristics for both lossless and lossy cases. To quickly solve the complex roots of the ARROW, a set of accurate closed-form approximations for estimating both the field distribution and complex propagating constant have been derived from the CE¡VCH matrices. These first-order approximations provide six significant figures of the real part of the propagation constant

Polymer based optical waveguides on silicon substrate were fabricated and the characteristics of the polyimide used were investigated. The optical waveguides were designed according to the simulation results calculated by beam propagation method. The fabrication began with spinning and curing two polyimide materials as the cladding and the core layers on silicon substrate. The refractive index of polyimide was obtained by prism coupling system. The index contrast was 0.67 % and the waveguide was the ridge type structure obtained by reactive ion etching process. Then a top cladding was spun on the sample and cured to complete the waveguide fabrication. Finally, the propagation loss of the TE mode of the waveguides was measured by using cut-back method. The loss was 2.4 dB/cm.

Ringdown spectroscopy (RDS) is an absorption spectroscopic and detection technique that makes use of an optical cavity to realize a long effective pathlength through a sample and to render the measurement independent of intensity. These two features give RDS an advantage over traditional absorption techniques and allows its application in measuring concentrations of strongly absorbing analytes present in trace amounts, or in measuring weak absorptions for analytes in higher concentrations. The resonant optical cavities used here are created from optical fibre. This permits the easy construction of an inexpensive apparatus for RDS. The performance of various cavity geometries (linear, circular) in three ranges of the visible and near infrared spectrum (405, 800, and 1550 nm) was examined. Concurrent multiexponential decays arising from core modes, cladding modes, and amplified spontaneous emission were analyzed in the framework of an exponential decay model transformed into the frequency domain. The small mode field diameter of light within a fibre is well suited to probing very small liquid volumes on the order of pico- or femtolitres. This uniquely positions optical waveguide-based RDS for application in absorption detection for separation techniques such as capillary electrophoresis (CE) and high performance liquid chromatography (HPLC) where high time resolution detection is required across narrow separation channels. The experimental and theoretical work presented here was preformed with an eye towards this purpose. / Thesis (Master, Chemistry) -- Queen's University, 2007-07-04 16:23:53.173

A chalcogenide glass (arsenic-trisulfide, As2S3) optical waveguide is vertically integrated onto titanium-diffused lithium-niobate (Ti:LiNbO3) waveguides to add optical feedback paths and to create more compact optical circuits. Lithium-niobate waveguides are commonly used as building blocks for phase and amplitude modulators in high speed fiber communication networks due to its high electrooptic coefficient and low mode coupling loss to single-mode optical fibers. Although it can easily be modulated using an RF signal to create optical modulators, it lacks the intrinsic trait to create optical feedback loops due to its low core-to-cladding index contrast. Ring resonators are main building blocks of many chip-scale optical filters that require these feedback loops and are already demonstrated with other material systems. We have, for the first time, incorporated As2S3 as a guiding material on Ti:LiNbO3 and fabricated s-bends and ring resonators. We have examined As2S3-on-Ti:LiNbO3 waveguides at simulation, microfabrication, and optical characterization levels.

No description available.

A study is hereby presented on system embedded photonic interconnect technologies, which would address the communications bottleneck in modern exascale data centre systems driven by exponentially rising consumption of digital information and the associated complexity of intra-data centre network management along with dwindling data storage capacities. It is proposed that this bottleneck be addressed by adopting within the system electro-optical printed circuit boards (OPCBs), on which conventional electrical layers provide power distribution and static or low speed signaling, but high speed signals are conveyed by optical channels on separate embedded optical layers. One crucial prerequisite towards adopting OPCBs in modern data storage and switch systems is a reliable method of optically connecting peripheral cards and devices within the system to an OPCB backplane or motherboard in a pluggable manner. However the large mechanical misalignment tolerances between connecting cards and devices inherent to such systems are contrasted by the small sizes of optical waveguides required to support optical communication at the speeds defined by prevailing communication protocols. An innovative approach is therefore required to decouple the contrasting mechanical tolerances in the electrical and optical domains in the system in order to enable reliable pluggable optical connectivity. This thesis presents the design, development and characterisation of a suite of new optical waveguide connector interface solutions for electro-optical printed circuit boards (OPCBs) based on embedded planar polymer waveguides and planar glass waveguides. The technologies described include waveguide receptacles allowing parallel fibre connectors to be connected directly to OPCB embedded planar waveguides and board-to-board connectors with embedded parallel optical transceivers allowing daughtercards to be orthogonally connected to an OPCB backplane. For OPCBs based on embedded planar polymer waveguides and embedded planar glass waveguides, a complete demonstration platform was designed and developed to evaluate the connector interfaces and the associated embedded optical interconnect. Furthermore a large portfolio of intellectual property comprising 19 patents and patent applications was generated during the course of this study, spanning the field of OPCBs, optical waveguides, optical connectors, optical assembly and system embedded optical interconnects.

A key factor in the vertical integration of optical waveguide devices is the uniformity of the surface across which the coupling takes place. This thesis focuses on the fabrication of annealed proton-exchanged (APE) waveguides vertically integrated with chalcogenide waveguides. While titanium diffused waveguides form a surface bump that is approximately twice the size of the originally deposited film, an annealed proton-exchange process produces waveguides with surfaces having 90% less deformation. The theory behind wave guiding devices is explored in this work along with the modeling and simulation of APE waveguides. The results obtained from the simulations are used to aid in the fabrication of these devices. A detailed review of the fabrication process of APE waveguides and chalcogenide waveguides is provided with results obtained from measurements. The first known coupling results for vertically integrated chalcogenide waveguides on top of annealed proton-exchanged waveguides are recorded. This work is concluded with future directions for this research including lowering losses by obtaining better simulation parameters and vertically integrating ring resonators along with ways in which to do this.