Zhe Zhang, Min Zhou, Chao Wang, Yingying Wang · 7 authors
A new approach to conquer the thermal phase drift of an optical fiber Fabry-Perot interferometer (FPI) sensor is proposed and experimentally demonstrated. By employing a hollow-core anti-resonant fiber (HC-ARF) and optimizing the fusion splicing (includes mode field adaptation) between the lead-in single-mode fiber (SMF) and the HC-ARF, a high spectral resolution ( λ /Δ λ ≈ 3.8 × 10 4 ) optical fiber air-cavity FPI sensor with a fringe visibility higher than 7 dB is constructed. To eliminate the thermal phase drift (i.e. temperature crosstalk) of the sensor that originates from the intrinsic thermal expansion effect of the silica material of the HC-ARF, the FPI air cavity is connected to the external environments, by which the effect of air expelling from the cavity with temperature increasing can well compensate the temperature-induced cavity elongation. As a result, the thermal phase drift of the FPI is reduced to zero at a temperature range of ∼ 80–110 °C and within the temperature range of 40–80 °C, the thermal phase drift is still halved compared with the sealed FPI cavity. The nearly zero thermal phase drift of a FPI at such a temperature range has never been achieved before, to our best knowledge. As a proof of concept, a temperature-immune fiber-optic strain sensor is demonstrated. This work offers a new and efficient approach to eliminate the thermal phase drift (i.e. temperature crosstalk) of a fiber-optic device, which may significantly improve the measurement accuracy and detection limit of fiber-optic FPI sensors. Furthermore, the principle and schema can be generalized to a wide variety of fiber-optic devices.
Florian M. Arnold, Gordon Lemme, M Hess, S Witt · 5 authors
Abstract The effort for checking and correcting the spatial movement accuracy of a processing machine with 5 axes is very high. Calibration and recalibration must be carried out directly on the machine by the machine supplier or a company specializing in this. This is associated with high personnel and long machine downtimes. These constraints can be improved by using modern methods. A consistent approach of an AR-supported measurement procedure for the preparation and execution of a required measurement run and the execution of the calibration itself as a digital service is presented. This enables rapid execution by the machine operator himself using a DoubleBallBar measurement system without the need of the presence of the machine manufacturer. The determination of the calibration parameters on the basis of the measurement data is then carried out by the machine manufacturer and provided as a service. The basis for such a secure and auditable service is a digital service platform. This serves as an intermediary between the user and the machine manufacturer and uses distributed ledger technology. The approach presented is the subject of current development work.