A few years ago, Micron Optics responded to a request from the FAA to create a fiber optic (FO) version of an embedded strain sensor for asphalt pavement. They were looking for a sensor that reduces cabling runs and is not susceptible to interference from lightening or other electrical noise.

The standard asphalt strain sensor at the time was an 8-inch long H-Bar gage based on electrical resistance foil strain gages. Micron Optics modified its os3600 gage to mimic the traditional gage and worked with the FAA to install two such gages and two FBG temperature sensors.

The results were interesting. The FO gages measured strains side-by-side with the electrical resistance H-Bar gages. The FO strain measurements tracked the expected values, and they exhibited no noise in the measured signal. (Noise was an ever present problem with the electronic gages.) After a few passes of the paver, one of the fibers was broken and two of the four sensors were lost. The quick prototype did not go far enough to protect the fiber, but still the fundamental performance was promising.

Fast forward to a few weeks ago- Applied Geomechanics (AGI), a key Micron Optics integrator with both FO experience and a long history with (and provider for) the standard H-Bar strain gages, installed several types of FO gages in another FAA test. Results were very good. The new FO sensor design allowed for placement in between layers of hot mix asphalt during construction as well as surface embedment in both asphalt and concrete surfaces. All sensors survived installation compaction and rolling and were immediately used for data collection.

The bottom line is that AGI will be moving forward with their customers in using FO gages for long term pavement studies for roads, bridge decks and runways. Read the full case study “Fiber Optic Sensing Solutions for the FAA Case Study” on AGI’s website.

We are frequently asked, “Why is Micron Optics’ swept laser (SL) technology so prevalent in the marketplace?”

Micron Optics’ patented, SL technology is built upon the highest performing and reliable optical-scanning technology known today: the Fiber Fabry-Perot Tunable Filter (FFP-TF). Its simple and elegant design allows our lasers to:
• scan wider (up to 360nm)
• tune faster (up to 100KHz)
• probe deeper (signal-to-noise ratio exceeds 75dB)

It is important to note that this is a swept, not tunable, laser. The swept laser scans the optical spectrum continuously, effectively providing infinite optical resolution; whereas a tunable laser scans in discrete wavelength steps. There is nothing to wear out in the Micron Optics SL design – no gears or motors. It is inherently rugged; in fact, it has survived shock tests to well over 3000 g’s!

This superior optical performance translates to valuable measurement performance characteristics like large sensor capacity (the wider the scan range, the more sensors can be monitored), fast sampling rates, high accuracy (a verifiable, NIST traceable 1pm) and long-term reliability.

Micron Optics’ SL technology is ever-improving too. Our Product Development team is devoted to constant design enhancements and reliability improvements. Micron Optics’ SL technology simply provides more capable, more versatile, and more reliable lasers than other designs.

NI Week is National Instruments’ annual worldwide conference on measurement and automation. In this forum, NI announces its most exciting new products. In this year’s keynote, NI announced in spectacular fashion their first FBG interrogator instrument — the PXIe-4844.

This new interrogator is a result of a deep engineering collaboration between Micron Optics and NI. It combines several important technologies and capabilities:

1) Micron Optics’ world leading swept laser optical sensor interrogation technology
2) Micron Optics’ patented, NIST traceable wavelength calibration technology
3) NI’s rugged and versatile PXI Express instrumentation platform
4) NI-OSI Explorer for configuration and NI-OSI LabVIEW Driver Software for application development in NI LabVIEW
5) NI’s worldwide sales, marketing and support organization to promote FOS solutions

NI and Micron Optics share a similar vision for FOS applications. That is, the unique advantages of fiber sensors will complement, and in some cases will work side by side with, conventional electrical based sensors. Broader availability and awareness of FOS interrogators and sensors surely help engineers and scientists solve measurement problems that may have been unsolvable until now.

Of course we’re pleased that NI chose Micron Optics to design and build the core of their interrogator, but perhaps it’s even more important that this large, well respected and influential company is investing in introducing FOS to thousands of new users. We think that all users, manufacturers, and sellers of FOS technologies will benefit by NI’s bold entry into this technology.

Previously in this blog, and elsewhere, we’ve extolled the virtues of FBGs — like their small size, immunity to EMI, and resistance to corrosive environments.  In a recent paper in the Journal of Power Sources, Nigel A. David and a team from the University of Victoria, Canada have demonstrated the importance of each of these FBG sensor characteristics for their application.  David and his colleagues are interested in polymer electrolyte membrane fuel cells.  These are thin, flat structures that have an electrochemically active environment inside.  David et al detail how others have tried electrical and infrared optical techniques to characterize the performance of PEMs and how these methods come up short.  David concludes that using embedded FBG sensors “reliably measure[s] temperature dynamically with a relative resolution of less than 0.2 DEG C,” and is an inexpensive approach that may prove useful for understanding current distribution across the PEM cell.

FBG measurements in this study involved both Micron Optics instrumentation and sensors, specifically the sm130 Optical Sensor Interrogator and os1100 FBGs.  See the full paper at: Science Direct