By Bengt O. Hallberg

In 1987, BOH Optical AB was a global leader in WDM technology, working in collaboration with Nokia in Finland and NKT in Denmark.

Catch-22

Letter from Televerket (the Swedish Telecommunication Authority) dated October 27, 1987. I will quote the concluding paragraph (translation from Swedish): “Since the Televerket Group currently lacks sufficient expertise to manufacture this type of equipment, the Televerket Group is unlikely to be suitable as the industrial partner BOH Optical requires. I would therefore encourage you to contact Ericsson.”

I found myself in a Catch-22 situation. In the monopolized Swedish market of the time, with only two players—Televerket, the operator and developer of cellular telecommunications systems; and Ericsson, the manufacturer—I was back where I started in 1981. That was when my doctoral studies were interrupted because Ericsson lost interest in the WDM technology. Funding for the project at IOF was then cut off.

U.S.

By 1988, the only remaining option was to go to the United States. All doors were closed in Sweden. Do you remember Dr. Michael Salour, my colleague who tragically passed away in a plane crash in 2023? I mentioned him in a previous blog post. At that time, he was constantly evolving his business in Carlsbad, California. He wasn't the only one; other high-tech companies had also established themselves there and were growing.

There were vacant premises and laboratory facilities next to his business. I began planning to relocate BOH Optical AB’s operations there. I had a post office box with a U.S. address for the company in nearby La Jolla. This was important in this context. A local contact handled the collection of mail.

I arranged my children's schooling, and I looked into job opportunities at an architecture firm for my wife. As for housing, I was quite familiar with the area. In the early 1980s, I helped a colleague who was working with Dr. Salour and his wife find a house to buy in the area.

As fiber optics were developed for telecommunications, the personal computer market evolved alongside them. Around this time, Americans established their dominance in the computer industry in other parts of California. A similar situation occurred in Sweden in the cellular telephony sector.

IBM computers ran Microsoft software, while Apple’s Macintosh offered an alternative. Apple’s design was based on an all-in-one, well-functioning, proprietary solution, while IBM’s was open. I purchased both types of computers for my company. The first Macintosh was released in 1984. It was intuitive to use, and only a few hours of training were needed to get started. IBM’s solution, on the other hand, was significantly more complicated. Windows 1.0, which improved accessibility, was released at the end of the following year. However, it did not improve accessibility to the same extent as the Macintosh.

In the first half of 1988, I had to make a crucial decision about moving to the U.S. with my family—my wife and our three children, the youngest of whom was only three years old. I had inherited a house in the Stockholm archipelago in 1986, so even if we sold our Stockholm home, we would still have had a permanent residence in Sweden. Unfortunately, my wife didn’t want to take a chance on living in the U.S., so she said no.

Between 1976 and 1986, all of our grandparents had passed away. This included my father and mother-in-law. My wife’s cousin, with whom she had spent a lot of time growing up, died young, leaving behind a husband and three children. It hit my wife hard. My father-in-law’s cousin, who was like a brother to him, also passed away.

Despite these losses, we had our children, enjoyed our jobs, and relaxed together on weekends in the archipelago. Those were the positive aspects of our lives back then. After twenty years together, we went through perhaps the worst period of our lives up to that point. I thought a change of scenery would help.

I don’t blame my wife. She was a pioneer as a female construction engineer in the 1960s and had an interesting job at an architecture firm. She was also one of the first to learn CAD drafting.

On Hold

The only option left was to put the WDM project on hold. It turned out that the market for such systems didn’t take off until well into the 1990s—more than a decade later. A quick online search revealed that global revenue for fiber-optic WDM technology is estimated to reach around USD 15 billion in 2026. However, it is unclear whether this figure includes wavelength-stabilized TX units. This translates to significantly higher revenues for fiber-optic systems with WDM.

The NMT cellular telephone system, developed by Televerket, took three decades to be ready for public launch. It launched in Sweden and Norway in 1981 and in Denmark and Finland the following year. If my WDM projects had received comparable resources over the course of a decade, they could be world-leading today.

Before concluding the discussion on Sweden's overlooked WDM breakthrough, I would like to acknowledge the individuals and teams who contributed to the development of these systems in various ways or had a professional interest in them. They are:

• Jan-Erik Falk, engineering technician specializing in precision mechanics
• Jean-Pierre Laude, Jobin-Yvon, representative, mux/demux units for the drop/insert system
• Leif Stensland, KTH/IOF, group leader, R&D fiber optics
• Martin Kull, KTH, master's thesis in connection with BOH Optical AB, later Ph.D.
• NKT Electronics team including: Erik Hornung, and Frits Thaulow
• Nokia team including: Gunnulf Mårtenson, Leif Wikberg, and Rune Udd
• Palle Jeppesen, Ph.D. and professor, Danish University of Technology, facilitator BOH and NKT
• Rune Lidholt, Ph.D., Holtek Optronics AB, fiber-optic connectors
• Stefan Johansson, Ph.D., KTH/IOF, group leader, R&D holographic gratings
• Sten Hugo Rislund, BOH Optical AB, electronics design engineer
• Sven Ingemar Ragnarsson, Swedish National Board for Technical Development, program officer, funding
• Televerket team including: Lars Egnell, Ph.D., Lars-Erik Eriksson, Ph.D., Mathias Grönberg, and Olle Blomdin

Lastly, I would like to acknowledge all the contributors subordinate to or collaborating with the aforementioned individuals with whom I did not work directly on the project.

Kurt Katzeff of Televerket signed the letter that halted the WDM project in Sweden. I will leave it to journalists and historians to investigate the background of that unfortunate decision.

One positive development in this context was a letter dated December 29, 1987, from Rune Udd, head of transmission systems at Nokia Telecommunications. They were prepared to continue supporting BOH Optical AB at the same level as before. Nokia offered to share their expertise and production knowledge to continue building complete systems.

Ernst Alexanderson

Later, I read about another Swede from the Royal Institute of Technology (KTH) who was several generations ahead of me in the telecommunications industry. Ernst Alexanderson (1878–1975) earned his Master of Science in Electrical Engineering in 1900. He immigrated to the United States in 1901 and found employment at General Electric before working at the Radio Corporation of America.

He made significant contributions to the development of wireless telecommunications and television. Alexanderson focused particularly on transmitters for the wireless systems. Does that sound familiar?

We were both working with photons. He worked with long wavelengths for radio, and I worked with the infrared range for fiber-optic WDM technology. Although there were already manufacturers of passive multiplexers and demultiplexers for fiber optics, none of them were producing complete systems close to being mass-produced. As far as I know, my company, BOH Optical AB, was the first in the world to achieve this.

I think Alexanderson enjoyed being at the forefront of a high-tech field that was right on trend. He wasn’t following in others’ footsteps, but rather, he had others following in his. Reaching his level requires a combination of many positive qualities. A broad, high-level knowledge of STEM is essential.

It also takes preserving the creativity with which we are born and having a strong personal drive and courage to take on challenges and venture into the unknown. By deciding to move to the U.S. the year after graduating from KTH, he clearly demonstrated his possession of these qualities.

Unfortunately, he passed away in 1975, the year before I started working on my fiber optics thesis at KTH to earn my Master of Science in Engineering Physics. It would have been wonderful to travel to the U.S., meet him, and hear him talk about his life and achievements. He is one of the many people Swedes should be proud of and honor in public forums, not just in closed STEM circles.

He lived and worked in the New York–New Jersey area, undoubtedly the right place to be at that time. For example, Thomas Alva Edison moved his laboratories to West Orange, New Jersey, in 1887. Then, in 1925, Bell Telephone Laboratories was established in Murray Hill, New Jersey. It was still one of the world's leading scientific research institutions in the 1980s.

I got to know several of the scientists there early on. They participated in the Advanced Study Institute on Fiber and Integrated Optics in Cargèse from June 23 to July 1978. Many of the world’s leading scientists gathered there to give lectures and discuss their research. For me, it was an important milestone in my career.

Alexanderson also made groundbreaking contributions to the development of television. This occurred in the 1920s. However, it wasn't until 1950 that KTH in Stockholm began conducting practical experiments to develop the technology and meet Sweden's needs. Hans Werthén (1919–2000), who had an Master of Scince in Electrical Engineering from KTH, spearheaded the effort with his colleagues. Werthén later served as chairman of Ericsson’s board of directors from 1981 to 1990.

Alexanderson’s contributions demonstrated the importance of colleges and universities in providing the best possible foundation for scientific education and research. Very few educated individuals possess the talent and drive to be the first to take the leap into the unknown without following in others' footsteps.

The next most important group is those who closely followed in his footsteps, build on his work, and help bring his findings to fruition. When science is transformed into products, collaboration between academics and skilled craftsmen ensures its realization. After the products are in place, the salespeople make sure they reach the users who need them.

Seamless Progressions

For the entire chain to function seamlessly, there must be uninterrupted funding for each link. It is also important that each link has qualified representatives who understand their role in the bigger picture and can take the lead within their scope. In the U.S., for example, the entire chain functioned effectively, leading to success.

Unfortunately, a crucial link was missing in Sweden for the WDM project. The part of the chain that had been created remained inactive for over a decade until someone else took over, added the missing link, and reaped the rewards.

A Bright Future Was Possible

Had the project continued, the collaboration between Nokia and BOH Optical could have resulted in a world-leading position in this field. This would have complemented Nokia's subsequent successes in the cell phone industry.

Although I didn’t reap the rewards when WDM became a key technology and gained widespread acceptance, I’m gratified to have helped establish the concept in Sweden, Denmark, and Finland. I was likely the first in the world to develop systems close to mass production in 1985 and 1987, respectively.

Next Blog

My next blog post is scheduled to be published on Tuesday, April 28, 2026. It is the first in a new series focusing on pivotal moments in the development of fiber-optic communication in Sweden and around the world since 1988.

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