Papers by Keyword: Waveguides

Abstract: Characteristics of the symmetric coplanar strip line on multi-layer dielectric substrates expressed in analytic formulas have been obtained using conformal mapping. But in most previous presented papers, the metal strip is considered as infinitely thin or PEC while the influence of dielectric substrates are not considered. In this paper, the propagation characteristics of symmetric coplanar strip line with finite conductivity and finite metal strip thickness on multilayer substrates are analyzed by conformal mapping at THz regions. The influences of metal strips and dielectric substrates on the propagation characteristics of CPS are also given. The numerical results are very useful for the development of terahertz devices and terahertz material.

Abstract: Channel waveguide formed by multi-energy O²⁺ ion implantation with different doses is analyzed at both 633 and 1539 nm. It has been demonstrated that the transverse mode number of waveguide is governed by the practical width of the channel waveguide, which depends on not only the channel width from pattern mask, but the lateral straggling of implanted ions. Beam propagation method (BPM) is employed to simulate the possible propagation transverse mode in the waveguides with different widths. The results at 1539 nm show that the waveguide keeps being a single mode waveguide until the width of channel is greater than 15 μm. At 633 nm, TE₂₀ mode can be obtained even the width of channel is very small, and the TE₃₀ mode begins to appear when the width is greater than 9 μm. These simulation results are in good agreement with the experimental results and the calculated results from Marcatilis method.

Abstract: In this paper the propagation of axially symmetric compression wave in an infinite transversely isotropic magnetoelectroelastic cylinder is presented. Following Pan(2002), the general boundary conditions on the surface of the magnetoelectroelastic cylinder are written by a simple vector equation that is similar to the purely elastic counterpart. By assuming the possible form of the solution, the generalized Pochhammer frequency equations are presented and the corresponding phase velocity curves in some range are given. Numerical examples are also presented to show phase velocity curves under the first 4 kinds of boundary conditions. Other boundary conditions can be studied under farther research.

Abstract: To achieve high-gain C-band waveguide amplifiers with integrated configuration, bent channel structures (S-, U-, and F-bend) based on buried Er³⁺/Yb³⁺ codoped phosphate glass waveguide channel fabricated by field-assisted annealing (FAA) have been designed in a 4´4 cm2 substrate. Using simulated-bend method, the optimal radius for the curved structure is derived to be 1.00 cm with loss coefficient of 0.0045 dB/cm. In the wavelength range of 1520-1575 nm, obvious gain enhancement for the bent structure waveguides is anticipated, and for the F-bend waveguide, the net gain at 1534 nm wavelength is derived to be 43.95 dB, which is much higher than the value of 26.67 and 13.20 dB in the U- and S-bend waveguides, respectively, and over three times higher than that of the straight one. The simulation results indicate that the bent structure designing is beneficial in obtaining high signal gain in buried Er³⁺/Yb³⁺ codoped phosphate glass waveguides, which lays the foundation for the further design and fabrication of integrated devices.