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121.
Different types of spot-size converters are studied numerically, and their coupling loss and reflection properties are discussed in detail. The rigorous vector finite-element method is used to calculate the modal propagation properties and the least-squares boundary residual method is employed to calculate the coupling loss, reflection coefficient, and the alignment tolerances of the devices. It has also been observed that the reflection coefficient reaches a minimum when the mode confinement is at its maximum 相似文献
122.
With the increasing interest in the use of optical-fibre interferometer measurement systems, the importance of the incorporation of low-coherence light sources is becoming of particular significance. In this work, the optical characteristics of different types of such sources in several interferometers are reviewed and examples are given. Their advantages in terms of increased unambiguous range, immunity to perturbation, high resolution and dynamic range, are discussed. 相似文献
123.
Results are presented for anisotropic waveguides, with an arbitrary permittivity tensor, being diffused in both the transverse directions and by using the finite element method with the vector H-field formulation for the analysis. The importance of considering the waveguide core dimensions to be greater than the diffusion depth in both the transverse directions, the use of extrapolation techniques and of a symmetry plane for anisotropic waveguides are also discussed 相似文献
124.
A finite element analysis, based on the variational procedure, is used to find the modal loss or gain for both the TE and TM modes with the application of the perturbation technique. Results for the modal gain for the buried heterostructure diode laser are presented, as well as the loss estimation for both the TE and TM modes for the asymmetrical multilayer metal-clad planar optical waveguides. The results obtained agree very well, for a wide range of loss/gain values, with the previously published work using alternative approaches 相似文献
125.
Wang D.N. Meggitt B.T. Palmer A.W. Grattan K.T.V. Ning Y.N. 《Photonics Technology Letters, IEEE》1995,7(6):620-622
A Sm3+-doped fiber pumped by an Ar-ion laser can produce a low coherence, visible light source for white light interferometric use. By the use of two spectral filters, a two wavelength combination source can also be generated flexibly and efficiently. This fiber light source is compatible with other fiber components in the optical sensor system, has good coupling efficiency into single mode fibers and high spatial coherence thus showing significant potential for this family of doped fibers, for use in white light interferometric sensor applications 相似文献