How AP Sensing is making cities smarter with fiber optic sensor technology

This interview with Bernhard Weihermüller (MBA 1995) was conducted by Katja Breitinger (MBA 2005) and originally published in Europolitan magazine in German.

Europolitan: How did the high-tech company AP Sensing come into being and what does it do today?
Bernhard Weihermüller: AP Sensing originated with Hewlett Packard. HP first began to develop electrical measuring instruments that were used in medical technology and chemical industries, among others. When fiber optics arrived in telecommunications, HP consequently developed optical metrology as well.The group spun off its metrology division in 1999 to form a new company, Agilent Technologies. Agilent Technologies' core business is chromatographs and spectrometers - in other words, medical products. 

For the area of fiber optic sensor technology in infrastructure projects, the best development opportunities were seen in an independent company. Clemens Pohl, one of the founders and the CEO of AP Sensing, established the fiber optic sensing business at Agilent Technologies, and spun off AP Sensing as a separate company in 2007. Today, AP Sensing is the global market leader in the increasingly important niche of fiber optic temperature and vibration measurement. 

Europolitan: How can you imagine these sensors? Are they small transmitters that are attached everywhere?
Bernhard Weihermüller: We are not talking about point sensors here, but about spatially distributed sensing over very long distances, where optical fibers act as sensors. The application is seemingly simple, but requires a lot of experience and expertise; the technology behind it is a small miracle.

AP Sensing has specialized in the two technologies of fiber optic temperature and vibration measurement. In both cases, an optical fiber is connected to a transmission and evaluation unit. The optical fiber itself is the sensor, it can be over 100 kilometers long, like a very long thermometer or a giant ear trumpet. The systems are used, for example, in the Eurotunnel, the Bosporus Tunnel or the Metrolines in New York City and Singapore. If there is a fire in the tunnel, the location and temperature are detected and an alarm is triggered. Since we know how fast light travels through the fiber, we know the location of the fire, because our technology allows us to determine exactly where a fault or fire is occurring, just like radar.

The interaction of the components can also explained with the image of a human body: A nerve conveys an impulse to the brain, and does so with varying intensity and with precise localization. The body parts themselves, in this case the urban infrastructure such as roads or subway tunnels, power grids and gas or water pipes, are not capable of doing this - unless they are are equipped with a sensor system (nervous system). AP Sensing's solutions thus consist of the sensor cables (nerves), the actual measuring instruments (brain) and corresponding software (intelligence). 

Europolitan: This sounds pretty simple at first, but it is certainly not. How does the technology work exactly and what is the crux of the matter?
Bernhard Weihermüller: The technique is based on various effects of quantum physics. As laser pulses are sent through the optical fiber, an interaction occurs between the electromagnetic wave of the light and the vibrations of the molecules in the fiber. The incident light beam is then scattered in all possible directions and as a response light comes back with altered wavelengths, this is the so-called Raman scattering. On the one hand, the temperature in the fiber can be determined from this.

On the other hand, acoustic events can be determined from other scattering components (the so-called Rayleigh scattering) when a leak occurs in a pipeline or an excavator impacts the earth or concrete with its shovel. The acoustic waves then travel through the soil and pass through the optical fiber.

The pattern of the backscattered light changes - an interference occurs, which is detected by measuring instruments. Now the signals have to be processed in a way the employees in the control center can understand them. The measuring instruments or the software evaluate the incoming signals and the software can graphically display the point of interference as well as further information, e.g. "excavator alarm" at the fault location.

The measurements generate vast amounts of data. In order to reliably distinguish whether, for example, a cow is walking over the cable hidden in the ground or an excavator is digging dangerously close to the cable, machine learning is utilized. It is now crucial to have the appropriate machine learning algorithms and to train the system during commissioning so that it functions reliably.

Europolitan: That sounds like quite a lot of physics. How are these principles translated into products?
Bernhard Weihermüller: Of course, the whole thing is a multi-stage process. The first step is to understand the market in detail and determine the specific needs. Based on this, we then develop platform solutions for the respective applications. Through conversations with the customer, the project-specific requirements are determined and documented. Based on these specifics, the optimal solution for the customer is selected. Depending on the customer's needs, data can be transmitted to a control center via defined interfaces, for example, or the customer is provided with a PC with the appropriate software. The final product is then installed at the customer's site, put into operation, extensively tested and handed over to the customer after approval.


Europolitan: This is all quite complicated ... You are responsible for the marketing department - how did you find AP Sensing and how long did it take you to understand what is being done here? And which colleagues do you work together with?
Bernhard Weihermüller: In the context of a professional reorientation, I was looking for a role in which I could combine my knowledge and experience as an engineer and as a marketing manager. Equally important to me is a healthy corporate culture which allows employees a great deal of creative freedom and is not primarily driven by short-term quarterly figures, but pursues a long-term and sustainable strategy.

The technology is absolutely exciting. As an engineer, I was enthusiastic about it right from the start and I am constantly learning. However, I also have a lot of respect for my colleagues who tirelessly develop solutions in a very complex environment and communicate on equal footing with both customers and less technically-oriented colleagues. AP Sensing employs people from around a dozen and a half different nations - Serbia, Canada, the USA, Russia, and India, for example. Our open-plan office creates a real sense of togetherness. Even collaboration with our CEO Clemens Pohl who also sits in the open-plan office, is generally possible within a very short time. For him it was important to him to create a working environment in which every employee sees their contribution and feels valued. Earning money at AP Sensing should be fun.

Europolitan: Where do you develop and produce? And how are the systems built on site?
Bernhard Weihermüller: The complete device development and part of the software development with machine learning take place in Böblingen. Production is right next door. This is an electrostatically protected area, so you shouldn't go in with normal street shoes, for example. The production area doesn't look particularly impressive - there are gray boxes the size of a microwave, some open, some closed. The production is a manufactory, each device is adapted to the special requirements and the customer's wishes and then, of course, extensively tested.

For example, control cabinets are currently being fitted in the so-called integration room, where a water pipe monitoring system for Neom City in Saudi Arabia is in the works. At the same time, the measuring instruments for a refrigerated high-bay warehouse in Singapore are being worked on. In the aisle, several two-meter-high wooden crates are ready for transport. They are destined for a power cable monitoring project in Bahrain. Working closely with customers, AP Sensing often has a Factory Acceptance Test (FAT) and a Site Acceptance Test (SAT) after installation at the customer's site.

Europolitan: What are the plans for the future? How will the company develop further? 
Bernhard Weihermüller: AP Sensing systems are increasingly used in renewable energy applications. For electromobility and the expansion of renewable energies, strong and stable transmission grids are essential, and we see an increasing demand in the future. Another future market is rail network monitoring. We are conducting research into this together with Deutsche Bahn. We want to be able to tell you exactly where a train is and how fast it is moving, down to the last decimal place. This will allow trains to run more densely and the rail network to be better utilized. We are certainly not running out of ideas. I am looking forward with great confidence and estimate that AP Sensing's sales will double in five years. 

Originally published in Europolitan by the ESB Reutlingen Alumni e.V., Edition 04/2022
Read the original (German) here or visit the ESB Alumni website here.