A novel 2-bit optical-input optical-output analog-to-digital converter (ADC) is demonstrated in self electro-optic device (SEED)
technology using a threshold logic technique. The threshold gate was
constructed using a resistor-SEED (R-SEED) which is composed of a large value resistor and a SEED area of 500 um x 500 um. Each gate operates as a majority function that has a threshold level controlled by a fixed optical input. The ADC was constructed using two R-SEED gates operating at wavelength of 846 nm. The test bench set-up operates at 100 Hz. However, as the proposed architecture is scalable, it can operate at much higher speeds and generate larger number of bits. This architecture is only limited by the switching speed of the SEED and propagation delay through each threshold gate.
As the demand for analog-to-digital (A/D) conversion with greater bandwidths increase, it is necessary to look at other alternatives to electronics for integrated circuit design. One such approach to utilize is a combination of optics and electronics, or opto-electronics, at all levels of the system hierarchy. A device that has these properties is the Self Electro-optic Effect Device (SEED), and combining this with oversampling techniques for data conversion can meet the demands for direct digitization of radio frequency (RF) signals. One form of A/D oversampling conversion method is Sigma-Delta modulation. A key element of this technique is the subtractor and in this paper we will discuss the implementation of a differential subtractor using SEEDs as part of a Sigma-Delta Modulator. This paper will detail simulation results based on experimental data to predict the behavior of two types of differential subtractors, one of which will be compared with experimental results.
Oversampled analog-to-digital conversion architectures provide a trade-off between sampling speed for improved amplitude resolution without the need for complex analog circuits. One form of oversampled data conversion techniques is sigma-delta (ΣΔ) modulation, which takes advantage of high sampling rates. In this paper, a performance evaluation on ΣΔ modulators based on measured data of Self Electro-optic Effect Devices are presented and discussed. The data are used in evaluating the performance of the A/D converter using MATLAB simulations.
This paper describes the analysis, design, construction and testing of two electrostatic wobble micromotors; a conventional cylindrical design and a new conical design. Both designs have stators with eight segments. The cylindrical micromotor rotor is about 4mm in diameter and 20mm long while the conical rotor has a maximum diameter of about 10mm and is 12mm long. The advantage of the new conical design is that it eliminates the need for a pivot and hence substantially reduces the size of the motor. A detailed theoretical analysis of the designs is shown and compared with experimental results. The micromotors are operated under open-loop control and the rotation of the rotor was tested at an applied voltage of up to 500V.