ICO Newsletter January 2002 Number 50

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ICO Prize for 2001 goes to Riza

Nabeel Agha Riza was born in Karachi, Pakistan, in 1962. He completed his Cambridge University (U.K.) “O” level and “A” level overseas school certificates in Lahore from St. Anthony’s High and Aitchison College, respectively. He then graduated from the Illinois Institute of Technology with a BS in Electrical Engineering in 1984, and from CalTech with an MS degree in 1985 and a doctorate degree in 1989. At Caltech, Riza pursued his doctorate studies with Professor Demetri Psaltis. He then joined the Liquid Crystal Display Laboratory at the General Electric Corporate Research and Development Center in Schenectady, New York, where he stayed from 1990 through 1994. In 1995, Riza joined CREOL where he is currently Professor and Head of the Photonic Information Processing Systems Laboratory. In Jan.2001, Riza launched Nuonics, Inc. to prototype his inventions. Over a decade of research, Nabeel A. Riza is responsible for the invention of several pioneering optical beam control structures that have strongly impacted fields such as array sensor controls, interferometry, signal processing, fiber-optic switching and controls, and optical scanning.

Realizing that any practical antenna control system requires both transmit and receive capabilities, Riza’s Ph.D. work showed how acousto-optics could be used for this dual function and developed a highly stable processor scheme. could be connected to the classic 1965 Lambert system to form the first all-optical phased array control system. At General Electric, he extended his original Acousto-optic Controller work to important wideband signal processing applications including spectrum analysis, correlation, and convolution. These were all performed with low component count, self aligning architectures. Riza next showed how his processor design could be further extended to form a novel space-time measurement tool that realizes a self-aligning, microsecond per point scanning speed interferometer for measuring optical phase/displacement with both high temporal (e.g., 1 ps) and spatial resolution (e.g., 0.1 nm).

Riza’s first introduction of nematic liquid crystal (NLC) device based phase and time delay control for antenna arrays was a critical innovation in the field. Riza was the first to show how the relatively slow millisecond domain switching speed of NLCs was not a limitation for most radar applications, if a time and space multiplexed optical control architecture is used for antenna beam scanning.

At CREOL, Riza’s group was the first to show how a polarization switched optical delay line could be constructed using low cost non-polarization maintaining fibers. This invention is particularly robust as it is essentially insensitive to birefringence changes in the fiber. Riza was also first to propose and demonstrate an active polarization noise reduction scheme for polarization-based cascaded photonic systems, demonstrating near 100 dB RF or 50 dB optical on/off isolation performance from limited extinction ratio liquid crystal switches. These and other methods are now being deployed in commercial products.

Riza was among the first to independently propose the use of optical microelectromechanical systems (MEMS) for realizing fiber-optic switches. Specifically, he proposed the use of thin-film micromachined optical actuators for making optical switching systems for phased array systems. More recently, Riza has invented ” SMP: Spatially Multiplexed Processing,” a novel concept for the realization of a new class of fault-tolerant fiber-optics that eliminate single point MEMS device failure. Riza has recently demonstrated fiber-optic attenuators using micromirror and liquid crystal technologies. Riza’s group models of fiber component coupling are now used in industry to optimize freespace-fiber designs.

Riza’s recent invention, Multiplexed Optical Scanner Technology or MOST, exploits polarization, wavelength, space, time, and optical codes to realize a new class of powerful multidimensional scanners with applications ranging from fast data retrieval in optical storage systems to agile optical wireless links. Other recent Riza inventions include a high speed, no moving parts, ultrasonic phased array scanning probe design using a single fiber cable and multiple wavelengths to deliver unprecendently small intracavity access, a secure optical communication scheme using spatial codes, a multi-level optical security system using multidimensional optical scanning of ID bio-information, and a 2×2 fiber-optic switch that for the first time uses fundamentally isolation limited (because diffraction is at best 90-95 %; hence isolation < 20 dB) acousto-optic devices to realize a very high > 60 dB isolation switch that also has a submicrosecond speed.

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