Papers by Keyword: Optical Waveguide

Abstract: Fresnel equations and transfer matrix approach are usually employed to solve for exact solution to Maxwell’s equations for multi-layered optical structures. In this paper, we demonstrate that the Fresnel equations and transfer matrix approach can be expanded using Geometric series. This geometric series give an insight to how the light is trapped and behaves in multi-layered optical structures. It also allows us to calculate multiple reflections and count the number of round-trip inside the structure. One main issue in optical calculation is that layers are usually treated as an infinitely large layer. This is, of course, not practical in term of device fabrication. We also demonstrate how this simple geometric calculation will enable us to calculate a smallest practical size that can accommodate a required optical resonant effect.

Abstract: In this paper, we demonstrate that Fresnel equations simulation for multilayer optical structures can be speeded up using impedance matching together with run once use many times concept as an optical responses database. The Fresnel equations can be solved by calculating reflection coefficient and transmission coefficient for each interface of the simulated structure and propagate the reflected waves and transmitted waves through the incident medium or the exiting medium using either scattering matrix approach or transfer matrix approach. If the structure parameter changes, such as, thickness of a layer in the structure change or the sequence of the layer changes, these require another set of Fresnel equations calculation. Here each of the layers are calculated separately with two semi-infinite layers with a fixed refractive index value sandwiched the two sides of the simulated layer. The reflection coefficient and the transmission coefficient for each layer can be then stored as a layer database. Different databases can be cascaded in any layer order to calculate a reflection or transmission responses of the layered structure.

Abstract: A micro biochemical sensor based on a SOI optical waveguide sensing platform is reported in this article. The sensing platform utilizes a Mach-Zehnder Interferometer (MZI) configuration. In order to satisfy the single-mode transmission condition of the waveguide and match the coupling size of standard single-mode fiber, a ridge waveguide structure is adopted to construct the MZI configuration. The key parameters of the waveguide are optimized by FDTD method. A process composed of contact exposure photolithography and Inductively Coupled Plasma (ICP) etching technology has been worked out for the fabrication of the optical waveguide sensing platform on SOI wafer. In the process, only one photolithographic mask is used. The mask is designed to have several patterns including an array of MZI configurations for multiple species sensing, a group of ridge waveguides with different key parameters as test references, and a group of geometric compensation schemes to test the methods of modifying the deviation which may arise during the ICP etching step. Process simulations are conducted to predict the exposure and etching results, which give strong support to the fabrication process control. Lithography problems including photoresist desquamation and line narrowing are solved to achieve the special structure.

Abstract: Aimed at the professional and printable materials, the researchers involved in higher payments, a new design scheme of utilizing MMA for 3D printing has been put forward based on its proper characters. The ideas and experiment frameworks are demonstrated, as well as the challenges are discussed.

Abstract: UV-Writing Poly(FPS-co-GMA) for optical waveguide was synthesized and the refractive index of the polymer film was tuned in the range of 1.460~1.555 at 1550 nm by mixing with bis-phenol-A epoxy resin. The film, which was made by spinning coated the Poly(FPS-co-GMA) with photo initiator, had good UV light lithograph sensitivity. The optical waveguides with very smooth top surface were fabricated from the resulting polymer by direct UV exposure and chemical development. The propagation losses of the channel waveguides were measured to be below 0.6 dB/cm at 1550 nm.

Abstract: Proton beam writing (PBW) has attracted much attention recently as a next-generation micro-fabrication technology. It is a direct-drawing technique and does not need any masks to transfer micro-patterns to sample surfaces. In addition, the refractive index of a poly (methyl methacrylate) (PMMA) can be increased by proton-beam irradiation. In this study, we fabricated the first 1.5-μm-band single-mode, straight-line waveguides and Y-junction waveguides consisting of PMMA layers using the PBW technique.

Abstract: Light propagation in an optical waveguide fabricated by employing a dye-doped liquid crystal (DDLC) was observed. The propagation of a light signal in the waveguide was varied by irradiation with a control light whose wavelength was in the absorption band of the DDLC. By considering the photothermal effect of the DDLC, which enables the change of the refractive index due to temperature variation based on the absorption of light, we qualitatively explained the observed light propagation and demonstrated manipulation of the propagation.

Abstract: The optical waveguides are produced in LiNbO3 substrate of three-component acceleration seismic geophone by lithography. Three-component acceleration seismic geophone detects changes in the external acceleration by detecting phase changes in the optical waveguides. The performance of optical waveguide directly affects the performance of three-component acceleration seismic geophone. Therefore, it is critical to measure and reduce the transmission loss of waveguides. The advantages and disadvantages of LiNbO3 crystal are introduced. The production process of Ti:LiNbO3 optical waveguide and its performance are presented. Some information about the types of transmission loss of optical waveguide and the measurement methods of optical waveguide loss are provided.

Abstract: Electrooptic waveguide technology is suitable for realization of an electro-optic 2x3 switch based on integrated Mach-Zehnder interferometer using polymer material, where ESO of polymeric materials were used. It can provide high performances and it is applicable for all optical switching networks. The relatively low cost technology, easy fabrication process with standard optoelectronic fabrication process and with high degree of integration compared to other technologies make the development of optical switch based on this technology favorable one.

Abstract: Optical waveguides have been known as basic structure in integrated optics. The result of waveguide analysis is very useful to apply before fabrication process begins. In this paper, optical propagation characteristic of straight waveguide on light intensity distribution within the structures have been investigated at 1.55 micrometer waveguide. The normalized propagation constant b and effective refractive index neff conditions have been considered for the straight waveguide for single mode propagation. Both the propagation characteristic can be calculated efficiently on the personal computer by using MATLAB programming. The analysis has been analyzed using a numerical method based on finite difference method approach. The result of optimization analysis of waveguide according to the parameter study can help in practical work in designing an optical waveguide easily.