Dr. Thomas Mensah:
Fiber Optics Innovator
Georgia Aerospace and AT&T

Dr. Thomas Mensah is one of the few chemical engineers who has had a worldwide impact on Fiber Optics Technology because of his pioneering inventions and patents in this industry.

He is one of the four original innovators and developers of fiber optics technology in this country. He holds 7 patents, all of which were awarded over the course of only six years. His training in chemical engineering and his talent for solving major industrial manufacturing problems led to the dramatic decrease in fiber optics manufacturing costs, from $1 dollar a meter to 10 cents a meter, leading to the replacement of copper wire cables with fiber optic cables throughout the Unites States.

This cost-effective innovation provided the much needed bandwidth which transformed the telecommunication and computer/internet platform that gave the US global leadership in this field. Prior to the advent of fiber optics, for example, internet communications were slow and pictures or large files took several hours to transmit because of bandwidth (information carrying capacity) limitations in copper cables. Today an entire encyclopedia can be transmitted in only a few seconds. Since the advent of fiber optics media, and its enormous bandwidth, data can now be transmitted at the speed of light.

Currently, over one billion people are connected to the internet because of the bandwidth offered by fiber optics. Long distance cell phone communications and ATM machines worldwide function efficiently because of fiber optics media. One can check account information all over the country at any ATM; physicians ocean apart can view x-ray pictures and video conference with one another using the internet- all of which are prevalent activities due to fiber optics.

When fiber optics technology was invented in the laboratories at Corning Glass Works, it was challenging to transition into the manufacturing environment, mainly because the delicate glass fibers (125 -150 microns thick) broke during any attempt to speed up production. For several years, the rate limiting step remained at 2 meters per second at the drawing and simultaneous coating stage. Dr. Thomas Mensah, then a young chemical engineer at Corning Glass Works Sullivan Park Research and Development Center, solved this worldwide problem through a series of inventions.

His first patent increased the manufacturing speed from 2 meters a second to 20 meters a second, bringing fiber optics costs to the same level as copper, thus, making it economical to replace copper cables with fiber optics media throughout the country.

High speed fiber optics manufacturing had unintentional consequences as well. During the coating process, bubbles were drawn into the coating applicator and became trapped in the ultraviolet energy cured coating near the glass interface. These bubbles led to light transmission losses and interfered with data transmission. Dr. Mensah used his understanding of boundary layer theory to invent a system that eliminated these interfacial bubbles. He received a second patent that involved the injection of carbon dioxide gases near the boundary layer at the top of the meniscus during the high speed coating process, which led to the elimination of any bubbles at the glass coating interface, producing optical fibers that met the high quality standards in the telecommunication industry. His patents touched all aspects of the draw and coating processes including the ultraviolet enhanced curing of the coating on the fiber. His final patent at Corning involved contact less monitoring of tension in the moving fiber based on laser detection of the fiber position and Fourier Transform Analysis.

Dr. Mensah went onto AT&T Bell Laboratories where he led a team in the development of a guidance system for smart weapons using fiber optics. At AT&T Bell Labs, Dr. Mensah had to wait a whole year before he could work in the manufacturing area because of a certain clause in his contract at Corning Glass Works. In the meantime, he focused his effort on the design and development of missile systems that are guided by fiber optics. He holds three patents in the fiber optics guided missile FOG-M technology, including the Guided Vehicle Patent.

In the fiber optic guided missile technology, a small camera in the nose cone of the missile captures pictures of a given target during missile flight. These pictures are digitized and sent over the optical fiber in real time to the cockpit so that pilots can identify targets and lock on them. The cross hairs seen on television when smart munitions are hitting targets are a staple in modern warfare and owe their accurate performance to fiber optics, GPS and/or other laser guided methods. Dr. Mensah is one of the early innovators in smart missile technology. He and his team developed missiles that were successfully deployed at Mach 1 (the speed of sound) using the FOG-M technology.

Current developments can allow a pilot to direct a smart missile or bomb through a window in a building without damaging other structures nearby. Precision guided bombs and smart missiles are a staple in the arsenal of the US Military and chemical engineers like Dr. Thomas Mensah have had and continue to play a major role in such advanced and innovative warfare.

In the current digital age, fiber optics and its deployment throughout the world has impacted all sectors of society, including various engineering disciplines, and has helped to give the US its economic leadership. Current and future technological innovations on the internet depend on this medium. This is evidenced by the recent acquisition of YouTube, an internet start up by Google Inc. for more than one billion dollars. The distribution of 15 minute length video on the internet is made possible by the enormous bandwidth of fiber optics. Chemical engineers like Dr. Tom Mensah have played a critical role in perpetuating the use of fiber optic technology throughout the US, leading to the advancement all kinds of applications from telecommunications (wireless and landline) to computer and internet platforms. All of these technological advancements have not only raised the productivity of engineers and other workers across the country, but have influenced US institutions like the Air Force and the American Military as they work to defend this country by using smart munitions and precision guided missiles.

Awards and Recognition

Contributions to the Profession and AIChE

Early Childhood Years

Dr. Mensah spent his formative years in Ghana and attended Adisadel College, an elite boys school in Cape Coast. Such elite schools in Ghana were very competitive and served as the training ground for future leaders in Engineering, Science, and Medicine. As one of the five sons of Mr. J. K. Mensah, a business man who bought and shipped cocoa to chocolate factories in France, Tom, at an early age, exhibited intelligence far beyond his age. His dad read newspapers to him while he sat on his lap and by age four he was reading newspapers in English. Tom's neighbor spoke French, and at the age of eight Tom was speaking French with European executives who visited his father for business meetings. He went onto win the National Competition in French two times and came to the attention the French government. Tom excelled in math and science and was awarded a scholarship to study chemical engineering at the University of Science and Technology Kumasi Ghana.

Some teachers who influenced Tom throughout his studies include Professor Francis Allottey, who taught Mathematics and Software Engineering and was the first black person to receive a Ph.D. in Physics at Princeton University; and Dr. Francis Aquah, Professor of Chemical Engineering, who taught transport phenomena and unit operations in the department.

After graduating at the top of his class with honors, Tom went on to win a French Government Fellowship to do graduate studies in Chemical Engineering at the University of Science and Technology (USTL) in Montpellier, France.

Tom's mentors and thesis advisors include Dr. Henri Gibert from Ecole National Superieur de Genie chimique (Leading Chemical Engineering School in France) at Toulouse. Tom received his Ph.D. in 1978.

Dr. Mensah also received a certificate in Modeling and Simulation of Chemical Processes at MIT in 1977, under Professor Larry Evans, 2007 President of AIChE. Dr. Mensah recruited additional mentors with his connections at MIT including Dr. Ken Smith, Provost at MIT, and Dr. Brian Thibault, MIT graduate and VP at Air Products and Chemicals.

After finishing his graduate work in France, Dr. Mensah joined the Chemicals Group at Air Products and Chemicals, as a Research Engineer, in the Polyvinyl Alcohol Process Improvement Division. In the lab, he developed simulations for the mixing process, where a highly viscous polymer, PVAC, was injected with a catalyst with viscosity around 1 centipoise. Mixing takes place in a thin film reactor which he simulated using the moving blade concept. The reacting mixture flows on to a moving belt where it cures into a white slab of Polyvinyl Alcohol. The slab is subsequently cut into pellets before drying. Poor mixing produces sections of uncured polyvinyl acetate and catalyst disrupting the cutting process leading to plant shut downs. After visiting the plant in Paducah, Kentucky, Dr. Mensah set out to duplicate the mixing process in the lab.

In his second year at Air Products he entered his findings in the annual competitive worldwide research forum and won a spot in this prestigious program. His presentation, judged by company-wide executives, won the second place award. In his lab simulations, he had developed an innovative approach by capturing on video the high speed mixing process using transparent wall mixers. He injected blue dyes in the polymer to simulate the catalyst during the reaction. Dr. Mensah detected that mixing was achieved through primarily Strauss secondary flows developed at the leading edge of the mixer blades. The center of the vortices in the secondary flows could trap poorly mixed reactants which were subsequently pushed on to the moving belt, leading to inconsistencies in the PVOH slab as well as plant problems and stoppages downstream.

Dr. Mensah solved this major industrial problem at the Polyvinyl Alcohol manufacturing plant at Paducah, Kentucky by changing blade configuration and notch depth, leading to a total redesign of the high speed thin film industrial mixers. He increased notch depth in the blades to enhance the mixing process. These changes led to increased plant efficiencies with no further process stoppages. The findings were published in the Chemical Engineering Communication Journal in 1985.

In the early eighties, Corning Glass Works was seeking an engineer to help increase manufacturing rates of their fiber optics plant. Dr. Mensah was hired to investigate this problem at their prestigious Sullivan Park Research Center in Corning, New York, where fiber optics was invented.

Dr. Mensah made history when he developed a system that increased manufacturing speeds from 2 meters a second to 20 meters a second, receiving an important patent that placed Corning Glass Works and the US in a leading role in fiber optics manufacturing. He received the Corning Glass Works Individual Outstanding Contributor Award for his innovations in fiber optics manufacturing process, including a $10,000 cash prize. A series of patents followed before he moved to AT&T Bell Laboratories where he continued his cutting edge research, this time, on the use of fiber optics to guide smart missiles, FOG-M. He received three additional patents on this technology.

Mentors and Role Models

Other Research Interests

In addition to fiber optics technology, Dr. Mensah has worked on thin film technology, most notably superconductors for space communication for NASA. He has recently designed and commissioned a state of the art radio frequency (RF), sputtering system, under ultra high vacuum, for making solid state rechargeable batteries for next generation cell phones. These findings were published in the proceedings of the Material Research Society Conference in Boston, 1995.

In the advanced composites area, Dr. Mensah has worked with the Department of Defense to develop new filament wound composite structures to replace gun barrels on new army tanks to reduce their weight. He published the Finite Element Analysis of these structures, focusing on the hoop stresses generated, the heat transfer, and the axial temperature profiles along the barrel during firing of the ballistics, in the proceedings of the Army Workshop in New Orleans, 1994.

Dr. Mensah has also worked with the Department of Energy, through a CRADA at Oak Ridge National Laboratories, on developing fiber optics-based sensors for intelligent highway traffic management.

Dr. Mensah and his team are working on the use of carbon nanotubes as reinforcement materials in next generation composite structures for novel supersonic missiles, a project under Contract from the US Air Force. These new missiles will exhibit advanced capabilities that will revolutionize current warfare. Applications of these new materials for space based structures, including satellites, are also envisaged.

Current Industry Contributions: Georgia Aerospace Corporation

Dr. Mensah's work in fiber optics guided missile technology made it easy for him to move into the Aerospace Industry. His expertise in materials, polymers and composites formed the foundation for his work in this field.

As founder and president of Georgia Aerospace, a company specializing in the manufacture and testing of novel composite structures for stealth aircraft, Dr. Mensah is in his element by bringing innovations to this new area. He is applying chemical engineering principles to design and develop structures for space launchers, satellite structures and advanced aircraft. New materials including nano-structural composites are being developed by his team at Georgia Aerospace for the US Air Force.

People he has admired throughout his career include Dr. Peter Schultz, one of the original inventors of fiber optics in Sullivan Research Park in Corning, who believed Dr. Mensah could solve the large scale fiber optics manufacturing problem and encouraged him until he developed the now famous Mensah Coating System at Corning. The device was installed on all fiber optics draw and coating towers in the manufacturing facility within a 100 million dollar plant. The plant went on to see an immediate speed increase by 10 times without glass breakage. Several other patents followed after this historic development.

Dr. Mensah wants to be remembered by his ability to bring all resources to bear on this worldwide manufacturing problem and impressively solving it in only six months. He is happy to bring so much joy to grandparents everywhere who can now download pictures of their grandchildren on the internet thanks to the wonders of fiber optics and his innovations in the field.

Advice to Young Chemical Engineers

• Luck is when preparation meets opportunity
• Excel in math and engineering courses
• Find mentors who can advise and help you in your career
• Gain industrial experience while going to school
• People skills are very important at all stages of your career
• Develop an understanding of the many new areas of science and engineering such as Nanotechnology (for example).

My participation in the American Institute of Chemical Engineers has helped me to develop leadership skills while finding mentors who were helpful to my career. Serving on the Board of Directors taught me how senior executives deal with tough problems.

I recommend participation at all levels by young engineers in the Institute from presenting papers to chairing sessions. Working in the emerging technology area and serving on the New Technology Committee kept me abreast of new developments in the field of chemical engineering.

The New Technology Committee and emerging technology areas must have active participation to help keep AIChEs programs relevant and keep AIChE at the forefront of chemical engineering innovation. For me, a new area of concern is the push into bio-energy with investors like Sir Richard Branson investing $3 billion in this area rather than investing in a new refinery. The alternative energy area deserves serious attention and could be made into a wholly new division, or at least operate on a separate platform like the nanotechnology area. The United States government's interest in this area, as well as the new tax subsidies for bio-fuels as an alternative to high carbon based fuel costs and environmental concerns (global warming), warrants that AIChE take a deeper look into this important area.

Select Publications by Dr. Mensah

1. T.O. Mensah et al, Radiation Effects on Optical Fibers; Proceedings of the European Conference on Optical Fibers , ECOC, Helsinki, 1987
2. T.O. Mensah; Enhancement of Strauss Secondary Flow Mixing in Thin Film Commercial Reactors, Chemical Engineering Communication Journal, 1985
3. T.O. Mensah et al, Analysis (Finite Element) of Composite Overwrap, Filament Wound Structures, Proceedings, Army Research Workshop Conference, New Orleans, September, 1994
4. T.O. Mensah et al, Optical Properties of Epitaxial PLT Thin Films, Proceedings of Material Research Society, Annual Conference, Boston, 1995
5. T.O. Mensah, Editor, Superconductor Engineering, AIChE Symposium Series Book Volume 88, No. 287, 1992
6. T.O. Mensah, Editor, Fiber Optics Engineering, AIChE Symposium Series, Book Volume 283, 1987
7. T. O. Mensah, US Patent number 5,035,169 Guided Vehicle System
8. T.O. Mensah, US Patent number 4,531,959, Method and Apparatus for Coating Optical Fibers
9. T.O. Mensah, US Patent number 4,636,405, Curing Apparatus for Coated Fiber
10. T.O. Mensah, US Patent number 5,064,490, Methods of Providing an Optical Fiber Package
11. T.O. Mensah, US Patent number 4,792,347, Method for Coating Optical Waveguide Fiber
12. T.O. Mensah, US Patent number 4,692,615, Apparatus for Monitoring Tension in a Moving Fiber by Fourier Transform Analysis
13. T.O. Mensah, US Patent number 4,955,688, Optical Fiber Package and Methods of Making

This profile was written by Dr. Thomas Mensah