1. IBM Corporation, San Jose, CA 95193
2. Hewlett-Packard Opto-Electronics Division, San Jose, CA 95131
3. Professor of physics at the University of Illinois at Urbana-Champaign, Loomis Laboratory of Physics, Urbana, IL 61801.
4. Senior Scientific Advisor at Exxon Research and Engineering Company, Annandale, NJ 08801.