Professor James Coleman, Intel Alumni Endowed Chair in Electrical and Computer Engineering, and former PhD student S. David Roh recently earned a United States patent for their research and development of the dual distributed Bragg reflector (DBR) grating semiconductor laser.
Written by By Bridget Maiellaro, ECE Illinois
James Coleman
Professor James J Coleman, Intel Alumni Endowed Chair in Electrical and Computer Engineering, and former PhD student S. David Roh recently earned a United States patent for their research and development of the dual distributed Bragg reflector (DBR) grating semiconductor laser.
Coleman said that one of the advantages of using lasers for communications is that multiple colors - wavelengths - of light can be transmitted through an optical fiber at the same time.
"Each color carries different information," he said. "The laser in this patent is a unique way to get more than one color of light from a single laser."
In addition, Coleman said that the multiple light waves can be mixed to produce new wavelengths the same way that radio signals are mixed to convert radio frequencies to audio frequencies. The improved device is unique because it is able to produce at least two laser lines at once.
"They are two laser lines of different frequencies, and you can mix them together to create terahertz radiation," he said.
As a result, the development is a hot topic that has both medical and security applications.
Coleman and Roh began researching and developing this laser about 15 years ago and filed for the patent in September 2000. After a long process of intermediate steps, the laser was officially patented March 4, 2008.
This is the seventh U.S. patent Coleman has obtained as a result of his research. He also has one Canadian patent.
"Patents endorse the work you’ve be doing," he said. "But then you get over it and get back to work."
With the help of his graduate students, Coleman is currently studying the structure and processes of unique kinds of lasers. He is also involved in a research project with ECE Assistant Professor Xiuling Li and her graduate students. One of Coleman’s main focuses, however, is developing a variation of the quantum dot laser, a semiconductor that uses quantum dots to show optical gain in its light emitting region, for a department of defense (DOD) program. In fact, Coleman already has had some of his research published, made presentations at conferences, and submitted a disclosure.