This study is meant to be an initial study of the possibility to replace the discrete control signal wires over the electrical coupler between train cars with a data bus system. The reason for this is that the electrical coupler is large and heavy due to the high amount of contacts it contains. It is also a problem for manufacturers who are upgrading an existing fleet and need to transfer more signals through a coupler with no spare contacts to use. Except the control signals there are also Ethernet and power signals in the electrical coupler. Some trains also use a bus system for control signals and/or signals containing a large amount of data such as passenger information.This report gives a presentation of some common ways to distribute electrical signals throughout a train used by most manufacturers. It also presents some design recommendations for a system that would collect existing signals to a bus system and two different design proposals that should be considered if such a system is to be developed. The study shows that there are already systems on the market for transferringcontrol signals over a bus but they are more aimed for trains under construction. Forthis reason a new bus system would only be suitable for upgrading existing couplersto free up space in the electrical coupler unit.

No description available.

In this dissertation, we study the fabrication and performance of fiber coupler, add/drop filter module, and flat-top interleaver for use in dense wavelength division multiplexing (DWDM) systems. In the low loss fused biconical taper coupler (FBTC), an optimum approach for fabrication of FBTC is a lower filament speed, a higher gas flow rate, and a longer pulling length. By applying this optimum approach that the FBTCs with low loss of 0.13 dB and small taper angle of 20o have been fabricated successfully. In the add/drop filter module, the module-insertion loss difference (0.3 dB) and angular tilt misalignment (0.05o) are found after undergoing 42 temperature cycles for the imperfect soldering process. We present our experimental results of a flat-top 50 GHz optical interleaver using two Gires-Tournois Etalons (GTEs) as phase dispersive mirrors in a Michelson interferometer. The spectral characteristics of the interleaver in a 50 GHz channel spacing application exhibit a 0.5 dB passband larger than 43.8 GHz (88% of the spacing), a 25 dB stopband greater than 40 GHz (80% of the spacing), and a channel isolation higher than 35 dB. The result shows that the interleaver interferometer with novel GTE technique can simultaneously produce a 0.5 dB passband and a 25 dB stopband wider than other interferometer techniques.

none

In this thesis, S-bend waveguides and ring resonant filters with multimode interference (MMI) couplers have been designed and fabricated. The single-ring filters are designed to have free spectral ranges ( FSR's) of 33.3GHz, 40GHz and 50GHz. The FSR's of double-ring filters are 100GHz and 200GHz. The splitting ratios of the 9-

This thesis addresses the design, analysis, and experimental validation of a high-directivity and high coupling microwave directional coupler. The motivating application is in broadband signal routing between cores of multi-core processors, where the delay of simple wire interconnects introduces unacceptable latency. The performance goals include scalability with frequency, a coupling coefficient of 3 dB, directivity larger than 40 dB, high return loss, low insertion loss below 3 dB at the center frequency, and small footprint. The approach to this problem taken in the thesis is a combination of edge and broad-side coupling in a multi-layer, multi-conductor microstrip coupled-line system. The two coupling mechanisms between neighboring pairs of coupled lines, along with appropriate end interconnections, allow for reduced size and design that achieves equal propagation velocities for the different modes supported by the five-conductor guiding structure that contribute to coupling. To validate the approach, a coupler designed for operation at 1 GHz is demonstrated to have a isolation of -22 dB with a coupling coefficient of 3\,dB and a return loss of -20 dB. The coupler is implemented on a FR-408 substrate with a permittivity of 3.66 and 1.17mm and 0.17mm thicknesses, and a total area of 12.65 cm^2. Three metalization layers are used in the design, with edge and broad-side coupled pairs of lines on the top two layers and diagonal end interconnects between the top and bottom lines. The coupler design is then scaled to 3 GHz by shortening the coupled-line length, and established -24 dB isolation, coupling of 3 dB, return loss of -20 dB, and has a total area of 6.9 cm^2. The analysis of the coupler shows that full-wave electromagnetic modeling agrees well with measurements and is necessary during the design process, while circuit analysis with built-in coupled-line models shows poorer agreement with experimental data. A tolerance analysis shows that the coupler performance is most sensitive to milling precision and separation between coupled-lines. Based on the measured and simulated results, it is shown that this type of coupler can be further scaled to higher frequencies and on-chip implementations for signal distribution in multi-core processors, or any other application where a number of components need to be interconnected with low latency and no reflection.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / During these times of acquisition reform in the federal government, various missile systems are being forced into using Commercial-off-the-Shelf (COTS) products in the design of their subsystems. However one problem that this presents is the lack of configuration management. There is a concern that the manufacturer will modify the product without informing the end user. This may have a severe effect on the performance of an already flight qualified subsystem. An example of how one program is dealing with this issue will be discussed.

The goal of the thesis is Ring Laser Integrated Taper-directional Coupler Using Deep Etching to Fabricate Total Internal Reflection Mirrors. In order to total internal reflection, we make deep etching for the total reflection mirror. We use the tapered waveguide coupler, if unidirectional traveling-wave oscillation can be achieved, spatial hole burning effects seen in DFB laser can be avoided. In this paper, two types of ring laser structures are fabricated and discussed, in which (1) 90 degrees total reflection mirrors and (2) circular retro-mirrors. In fabrication process, we get smooth waveguide and highly perpendicularity waveguide by Self-Alignement wet etch method. In order to reduce bending loss and waveguide loss, we make deep etching for the total reflection mirror and circular retro-mirrors.

Purpose of this study is to use adjustable platform for development of fiber diameter and fiber fusion from 125£gm to 50£gm,125£gm to 40£gm different taper single-mode fiber, the use of different process parameters in the design of fire taper models and parameters with the molten zone, the minimum loss of 0.77dB.After the large diameter quartz capillary tube inserted into some optical fiber taper changes made after the n¡Ñ1 optical combiner, and adjusted through the design taper model parameters reduce the firepower some fiber transmission loss. In recent years, the application of high-power fiber laser in various industries is widely spreading and exploring. Within the system, one of critical component is the fiber pump combiner. We are currently investigating the fabrication of 7x1 Combiner with both single mode and multimode fibers and the characterization of combiner efficiency as a function of processing. The development of 7¡Ñ1 single-mode fiber combiner loss of about 1.5dB and 7 ¡Ñ 1 multimode fiber combiner loss of about 1.4dB

This study uses vertical mirror optical waveguide reflector and bending waveguide to fabricate semiconductor ring resonators. By using multimode interference couplers with specific width and length that generate distinctive energy distribution to achieve the power splitting of 85:15. We integrate vertically deep etching turning mirror to reflect optical mode, and reduce the component size to 37.6%. In fabrication process, this study applies multiple wet etching technique to form the waveguide structure. First, we use wet etching technique to etch ridge waveguide and turning mirror, and then perform deep etching in the periphery of bending and turning region to reduce the bending loss. Finally, the etching mask is lifted off, and the wafer is polished and sliced for measurement. After measuring the signal, we can compute waveguide loss by Fabry-perot resonant situation. The waveguide loss is 59.6dB/cm. Power splitting of 90:10 is achieved. The free spectral range (FSR) is 72GHz for the ring resonators.