Produkter
Not exactly what you are looking for?
We offer standard force sensors but can also help you with a customized design or a complete measurement solution.
Fiber Optic Sensors: Precise Measurement With Maximum Flexibility
With fiber optic measurement solutions you can measure strain, pressure, displacement or temperature. Conventional electronic sensors are often hampered by distorting effects such as high voltage or EMV. This is where our systems come in: they open up new possibilities for reliable measurements, especially in the most challenging environments.
How does fiber optic WLPI technology work?
Fiber optic white light polarisation interferometry is a patented technology. It enables precise measurements in the most demanding applications. WLPI allows great flexibility in sensor design for reliable measurements even in the most challenging environments.
Fiber optic measuring systems comprise two main components: the fiber optic sensor and a signal processing unit. The fiber optic sensor consists of a sealed housing that contains the optical sensor element and an optical fiber, which serves different purposes depending on the technology used.
There are several fiber optic measuring procedures based on different properties of light (intensity, phase, polarisation, or spectrum). Depending on the procedure, variations in the designated measurement quantity causes one or more of these properties to change, so that the returning signal is altered.
Extrinsic and Intrinsic Sensors
光纤传感器s can be divided into two main categories: extrinsic and intrinsic sensors. They differ both in design and function, featuring specific properties that make them suitable for different applications.
In intrinsic sensors, the light conductor is an essential component of the measurement mechanism. The optical fiber is the sensor. Common examples of this category include sensors based on Fiber Bragg Grating.
Extrinsic sensors, on the other hand, are characterized by the sensitive component being separate from the optical fiber. The optical fiber merely transmits the light signal between the sensor unit and the evaluation electronics. Examples of extrinsic sensors include temperature sensors based on gallium arsenide crystals (GaAs) as well as the WLPI-based fiber optic sensors presented below.
Precise Optical Measuring Procedure
The signal evaluation unit feeds the light signal into the optical fiber, receives the reflected, altered signal, and processes it to output physical units of the measured quantity. The light source used can differ depending on the measuring procedure and technology.
Optical interferometry, which measures the phase modulation of light, is considered the most sensitive method of fiber optic measurement. An interferometer is a high-precision optical measurement device featuring two or more light beams that are guided on different paths through semi-transparent mirrors before being reflected and recombined by another set of mirrors. This results in an interference pattern which is determined by the difference between the optical paths taken by the individual beams before their recombination/superimposition.
Using interferometry lets you measure a physical quantity whenever variations in that quantity cause variations in the path length in the interferometer.
Laser vs. White Light
The lasers used as light sources in conventional fiber optic sensors led to issues with phase ambiguity due to their narrow bandwidth. This was due to the coherence length of the light source generally being larger than the difference in wavelength in the interferometer. As a result, possible applications for fiber optic sensors based on interferometry were limited. The solution to this problem lies in using a light source with a shorter coherence length and broader light spectrum.
This kind of interferometry is called white light interferometry or optical coherence tomography. The founders of Opsens are pioneers in white light interferometry for fiber optic measurements. They have refined this technology to commercial viability.