Ahmad Safaai-Jazi

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We propose a method for controlling modal gain in a multimode Erbium-doped fiber amplifier (MM-EDFA) by tuning the mode content of a multimode pump. By adjusting the powers and orientation of input pump modes, modal dependent gain can be tuned over a large dynamic range. Performance impacts due to excitation of undesired pump modes, mode coupling and(More)
(Abstract) Wide Area Measurements (WAMs) have been widely used in the energy management system (EMS) of power system for monitoring, operation and control. In recent years, the advent of synchronized Phasor Measurements Unit (PMU) has added another dimension to the field of wide-area measurement. However, the high cost of the PMU, which includes the(More)
Ultra wideband (UWB) wireless communication has been the subject of extensive research in recent years due to its potential applications and unique capabilities. However, many important aspects of UWB-based communication systems have not yet been thoroughly investigated. In particular, indoor channel modeling, interference effects, and the role of antennas(More)
UWB Channels can be measured by sounding the channel with pulses, and thereby obtain the impulse response. Multipath components have different waveforms depending on the type of transmitter and receiver antennas used and the angles of transmission and reception. A modified deconvolution technique is introduced to extract the UWB channel response. The(More)
—The application of a recently introduced microwave imaging technique based on the Huygens principle (HP), has been extended to multilayered objects with inclusions in this paper. The methodology of HP permits the capture of contrast such that different material properties within the region of interest can be discriminated in the final image, and its(More)
Using multimode fibers for long-haul transmission is proposed and demonstrated experimentally. In particular few-mode fibers (FMFs) are demonstrated as a good compromise since they are sufficiently resistant to mode coupling compared to standard multimode fibers but they still can have large core diameters compared to single-mode fibers. As a result these(More)
Optical sensors have been investigated and widely deployed in industrial and scientific measurement and control processes, mainly due to their accuracy, high sensitivity and immunity to electromagnetic interference and other unique characteristics. They are especially suited for harsh environments applications, where no commercial electrical sensors are(More)