30,000 Times More Accurate Measurements Thanks to Integrated Photonics

From the aerodynamics of aircraft wings to micro-vibrations in the high-tech industry: a wide range of industries have a pressing need for extremely accurate measurement systems. Technobis, based in Alkmaar, the Netherlands, develops just such measurement systems. Thanks to Integrated Photonics Technology, their measurement accuracy and reliability has increased considerably. It is now possible to take measurements just 50 nanoseconds apart, 400,000 times faster than a hummingbird’s wings, which flap 50 times per second.

Fibre optic sensors form the basis of integrated measurement equipment for instance incorporated in biopsy needles, aircraft and crash-dummies. As a fibre becomes stretched, it is possible to measure extremely accurately the change in wavelength (colour) of the light passing through it. Spectrometry and Interferometry are the physical concepts at the heart of the measurement equipment developed by Technobis to analyse the deformation of the optical fibres.

Technobis designs and builds technological platforms based on Photonic Integrated Circuits or optical chips. Previously the company worked with standard optical measurement systems. The disadvantage of these systems is that they are relatively large. While the ‘old’ solutions were a few square centimetres in size, the integrated photonics chip takes up just a few square millimetres. This compressed technology also allows for a much smaller chip casing while delivering far greater stability, both thermally and mechanically. This allows much smaller changes in wavelength to be measured, which would be undetectable to conventional measurement equipment.

Impressive improvements in measurement performance have been realised. Conventional measurement equipment is able to measure strain to an accuracy of 0.1%. With Integrated Photonics it is possible to take measurements 30,000 times more accurately. High-tech companies such as ASML have a pressing need for virtually vibration-free equipment which means that they have to use extremely sensitive sensor systems to achieve this. Thanks to the increased stability of Technobis’ measurement systems it is now possible to take wavelength shift measurements of less than a femtometer, i.e. measuring strain differences of less than a millimetre over 1000 kilometre. In addition, the equipment is much more precise in collecting falsifiable and verifiable measurements.

The system’s applications range is also vast in the field of extrinsic measurements. For aerospace and automotive industries it is of particularly importance taking measurements where little space is available, such as on the ribs of crash test dummies. At a speed of 20 kHz, it is possible to take a measurement every 50 microseconds. If a collision takes place in 20 milliseconds, the many measurements acquired will form a detailed impact and crash profile.

Damages and impact effects in composites structures in aerospace and space can now be made visible by taking high frequency measurements with devices that endure the strict environments. Composite material is light and strong but damage is often invisible externally. The frequency behaviour of the composite structure changes as it is damaged and is only measurable thanks to the small size and performance of Integrated Photonics. There is no practical and affordable solution thinkable with conventional equipment.

The shape definition and design of morphing structures can be measured by fibre optic sensing technology in aircraft wings, with the objective of improving the performance and maintenance of aircraft, to ultimately make flying itself more cost effective (better flight performance and lower maintenance costs). Measurement equipment for these applications must be as inexpensive and small as possible, while using as little power as possible. With the introduction of Integrated Photonics, operational and energy costs can be reduced by as much as a factor of 10 and the same applies to the dimensions of chip casings.

While applied Integrated Photonics Technology is a recent innovation, according to Technobis it is here to stay. Particularly since its possibilities are virtually unlimited in comparison with conventional solutions. Technobis is therefore focusing on the development and testing of various designs. This presents an opportunity for Technobis and the Netherlands as a whole to take the lead on the international stage… And continue to lead.

Source: Technobis group, RVO

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