M.Ing. / All-optical networks, although highly promising, have a long way to go before they will replace existing optical networks such as SONET. The development of the all-optical networks relies on the components market to supply reliable and integrated components to facilitate filtering and management in the optical domain. Planar lightwave circuits (PLCs) and photonic integrated circuits (PICs) provide the answer, with the potential of integrating various functions on a single substrate. The design of lightwave circuits starts with the design and testing of a waveguide. Once this manufactured waveguide exhibits the right characteristics and is proved to be reproducible, it can be used in the design of components. In industry, this design is done by utilizing the beam propagation method (BPM). In order to design useful circuits, the simulation results of simple structures should be compared with experimental results to check their sensitivity to certain parameters. Once the relationship between manufactured and simulated components is understood, the design of components can commence with confidence. In this thesis, BPM simulation results are compared with a reported manufactured waveguide, and then used to design various components used for filtering purposes in dense wavelength division multiplexed (DWDM) systems. Designs for the couplers that serve as building blocks for the filters are discussed, and a novel technique of design downscaling is presented for bi-directional couplers. The filters under investigation are all moving average filters, namely Mach-Zehnder lattice filters, and the highly integrated arrayed waveguide gratings (AWGs). Applications for both these filters are presented.

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Statement of work: In essence the research work was to focus on the development of an ionospheric model suitable for real time HF frequency prediction and direction finding applications. The modelling of the ionosphere had to be generic in nature, sufficient to ensure that the CSIR could simultaneously secure commercial competitiveness in each of the three niche market areas aforementioned, while requiring only minimal changes to software architecture in the case of each application. A little research quickly showed that the development of an ionospheric model capable of driving a HFDFSSL system in "real time" would result in one having to make only slight re-structuring of the software to facilitate application of the same model in the areas of real time frequency prediction and spectrum management. The decision made at the outset of the project to slant the research toward the development of a model best suited for HF direction finding applications is reflected in the avenues followed during the course of the modelling process

The generally accepted, though approximate, theory of the relaxation time T₁ of the nuclear spin system in ortho H₂ at low temperatures was developed by Schwinger (see Bloembergen (1948)). In this thesis Schwinger's theory is generalized to the case of arbitrary temperatures. An expression for T₁ is obtained which reduces to the Schwinger formula at low temperatures and ordinary pressures and to a slightly modified Schwinger formula at low temperatures and low pressures. The method used here to calculate T₁ is somewhat different from the method used by Schwinger. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Methods of setting up generalized Bloch equations governing the time dependence of macroscopic magnetization for a system of nuclei of spin I, in given magnetic and electric fields, have been proposed for the degenerate case by Bloom, Hahn and Herzog and by Lureçat, and for the non-degenerate case by Bloom, Robinson and Volkoff. In this thesis an attempt is made to give a unified discussion of these methods by utilizing the density matrix formalism and to demonstrate the interrelationship between them. Relaxation effects are not considered. The general theory is developed in terms of the density matrix formalism and is applied to the non-degenerate and the degenerate cases. The results are discussed and compared with those of the previous investigators. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis describes the design of a proposed, new hydraulic laboratory, wave generator for use in a 39'-4¼'' long, 30" wide and 36" deep flume, and the re-design of a small wave generator previously built for a 21'-3 5/8" long, 8 3/4" wide and 10 5/8" deep flume. These relatively short flumes are installed in the Hydraulics Laboratory of the Department of Civil Engineering, University of British Columbia, and the installation of the proposed, new wave generator would augment the present limited wave research facilities. The project is supported by an operating grant from the National Research Council of Canada. The preparatory study of laboratory wave generators in use, presented herein, was made to determine how they function and their design problems. It was concluded that a rigid paddle, double articulation type would be best for generating deep-water, transition and shallow-water waves in a flume of relatively short length. Biesel's wave generator theory is outlined and was used in estimating wave heights and in determining power and strength requirements. The existing wave generator for the "small" flume is a rigid paddle, double articulation type. It did not function satisfactorily due to a very irregular paddle motion. The causes were isolated and a new drive system designed and installed, with good results. The resulting new operating specifications are: power = 1. Hp (D.C.) wave period range = 0.34 to 2.1 sees. design water depth = 6.5" estimated maximum wave height = 4" The proposed, new wave generator for the "large" flume is a rigid paddle, double articulation type designed around the adjustable paddle concept of G.D. Ransford (1949) as modified by Lt. CB. Coyer (1953). The designed operating characteristics are: power = 10-Hp (D.C.) wave period range = 0.68 to 4.28 secs. design water depth = 25" estimated maximum wave height = 14" / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The behavior of elastic body waves in a dipping layer overlying an elastic medium has been theoretically investigated by a multiple reflection formulation. Although the diffracted wave is not included in this formulation, its importance is studied by investigation of the amplitude discontinuities within the wedge. For a plane SH wave incident at the base of the dipping layer perpendicular to strike, a series solution has been obtained. Numerical values of the amplitude, phase and phase velocity are calculated on the surface. For waves propagating in the up-dip direction the amplitude versus frequency curves for a constant depth to the interface change slowly with increasing dip for dip angles less than 20°. However for waves propagating in the down-dip direction the character of the amplitude curves change rapidly. In these cases, it is found that the diffracted wave plays an important role. In addition to satisfying the boundary conditions at the surface and the lower boundary of the wedge, the diffracted wave must also satisfy additional conditions along a dipping interface between the wedge boundaries due to the geometrical nature of the reflected wave solution. It is found that the phase velocities vary rapidly with both period of the wave and depth to the interface. For incident plane P and SV waves, the complexity of the problem due to the converted waves does not allow the solution to be expressed in series form. However, a computational scheme has been developed which allows the calculation of the disturbance due to the multiply reflected waves. For both incident P and SV waves, numerical values of displacements and displacement ratios are calculated on the surface. It is found that the displacement ratios for incident SV waves are much more sensitive to dip than are there for incident P waves. For incident P and SV waves propagating in the down-dip direction with a propagation direction [symbol omitted],β = 120°, the amplitude ratio versus frequency curves for constant depth to interface do not have significant peaks for dip angles greater than 15°. The maximum discontinuities caused by the outgoing wave are also calculated to determine the role of the diffracted wave. As subsidiary problems the energy relations between waves at an interface between elastic media are determined in terms of propagation direction in a cylindrical system and the complex propagation direction is interpreted using the Rayleigh wave. The final study is to determine by a reflected wave formulation the displacements due to periodic and impulsive line sources of SH waves in the wedge overlying an elastic medium. A formal solution is found by which the contributions due to head and reflected waves are determined by evaluation of the integrals by the method of steepest descent. Using ray paths, the contributions of the integrals have been interpreted. The range of existence of head waves has been examined and the discontinuities associated with diffracted waves studied. In the case of a free or rigid lower boundary of the wedge, the dispersion relation has been determined. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Experimental results are presented on the propagation of strain waves in long rods of mild steel (type-1020) aluminum (AA2024S) and copper (soft electrolytic). Strain pulses of order 500 μ in/in amplitude were generated by mechanical impact. The average strain rate during loading was of order one per second. The length and diameter of the specimens and the dominant frequencies in the strain pulses were such that one-dimensional conditions prevailed. Budd Metalfilm resistance type strain gauges were used for recording the strain pulses. Electromagnetic disturbances were effectively eliminated by proper grounding and shielding. Elastic wave propagation in mild steel, aluminum, and copper was studied. For the steel specimen, there was no apparent attenuation or dispersion of elastic waves. However, significant attenuation and dispersion were observed in aluminum and copper specimens, a 30 percent reduction in amplitude occurring in aluminum over a distance of 8 feet. Comparison of the Fourier transforms of the strain pulses in copper and aluminum at different positions along each specimen revealed that amplitude decreased exponentially with distance and that phase angle varied linearly with distance. Furthermore, the observed attenuation and phase velocity were frequency dependent. These results conform to the behaviour of strain pulses propagating in linear visco-elastic materials. Complex compliances for aluminum AA2024S and soft electrolytic copper were derived over the frequency range 400-6000 c.p.s. from the variation of attenuation and phase angle measured in these tests. Approximate three-parameter models suitable for estimating internal damping in these two materials were also determined. Plastic wave propagation in statically prestressed rods of aluminum and copper was investigated. In copper, it was observed that strain increments propagate at constant velocity along the rod and that the velocity of propagation decreases with increasing strain. Strain-rate independent theory is thus applicable to the description of plastic wave propagation in copper, but the dynamic stress-strain curve for the material lies well above the quasi-static one. Furthermore, experimentally observed loading-unloading boundaries in copper resemble the shape predicted by Skobeev and calculations based on these boundaries are compatible with the strain-rate independent theory. It was found that annealed aluminum (AA2024S-0) does not possess a smooth quasi-static stress-strain relation and exhibits unstable behaviour under dynamic loading. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

An analysis of a class of corrugated structures is given for the purpose of determining the extent to which slot evanescent modes affect the shape of the dispersion curve. The analysis also permits a critical examination of a previous prediction of conditional confluence in this structure. An existing analysis of the cylindrical slot-coupled cavity chain is presented and then extended to include the effect of higher normal modes. The accuracy of this extension is examined experimentally. A discussion of zero-mode conditional confluence based upon this theory is presented. Experimental confirmation of zero-mode confluence is made. The possibility of achieving conditional confluence in the centipede structure and the reversed-loop-coupled cavity chain is discussed. The discussion is based upon an analysis by Bevensee. Two confluence tests are presented to complement the existing one. Finally, a discussion on the usefulness of auto-confluent structures for accelerator applications is presented. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Accurate measurements of the propagation coefficient of the HE₁₁ mode on polythene-tube waveguides in air and surrounded by a polyfoam shield are reported. These were carried out at X-band frequencies using a cavity-resonance method. The results obtained confirm previous theoretical predictions although there is an element of uncertainty concerning the exact dielectric properties of the commercial grade polythene tubes used. The measurements also yielded the phase coefficient of the HE₁₁ mode which was confirmed by measurement of the radial decay of the electric field outside the tube. Enclosing the dielectric-tube in a low-density, low-loss polyfoam shield resulted in only a slight degradation of the attenuation characteristics of the waveguides. Measurements of the phase characteristics of the higher order TE₀₁ and TM₀₁ modes on the tube at frequencies close to cutoff are also reported. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate