High accuracy calibration method for 3D curve reconstruction based on a twisted multicore fiber

Area of Science:

• Fiber optics sensing
• Optical measurement systems
• Metrology

Background:

• Accurate three-dimensional (3D) curve reconstruction is crucial for various applications.
• Existing methods using twisted multicore fiber (MCF) face challenges in calibration accuracy.
• Precise calibration is needed to decouple fiber parameters and improve reconstruction fidelity.

Purpose of the Study:

• To propose and experimentally validate a high-accuracy calibration method for 3D curve reconstruction using a twisted MCF.
• To decouple and calibrate key parameters of the twisted MCF: core spacing, core azimuth, and twist bias.
• To evaluate the improvement in 3D curve reconstruction performance after applying the proposed calibration.

Main Methods:

• Development of a calibration approach based on amplitude, phase, and period information from strain curves.
• Experimental investigation of a 3D curve reconstruction system utilizing a twisted MCF and optical frequency domain reflectometry (OFDR).
• Systematic evaluation of reconstruction accuracy before and after the proposed calibration procedure.

Main Results:

• The calibration method successfully decoupled and calibrated the core spacing, core azimuth, and twist bias of the twisted MCF.
• After calibration, the average tip position error in 3D curve reconstruction was significantly reduced.
• For a 25 cm reconstruction length, the error decreased from 28.12 mm to 2.50 mm.

Conclusions:

• The proposed high-accuracy calibration method effectively improves 3D curve reconstruction performance based on twisted MCF.
• The decoupling of MCF parameters using strain curve information is a viable approach for enhancing metrology.
• This advancement offers a more precise tool for applications requiring accurate 3D shape sensing.