Optical fiber specklegram sensor for multi-point curvature measurements

Area of Science:

• Optics
• Fiber Optics
• Sensor Technology

Background:

• Existing shape sensing technologies often involve complex setups or computationally intensive processing.
• There is a need for straightforward, cost-effective curvature sensors for applications like medical probes and soft robotics.

Purpose of the Study:

• To develop and characterize a multi-point curvature sensor utilizing optical fiber specklegrams.
• To demonstrate the sensor's capability for accurate shape prediction in 2D and 3D space.

Main Methods:

• A reflection-type probe using an ordinary multimode optical fiber excited with visible light.
• Discretization of the fiber into segments with joints to simplify specklegram analysis.
• Correlation analyses of specklegrams to determine curvature without deep learning.

Main Results:

• Linear sensor response with a resolution of approximately 1.3 degrees for single curvatures.
• Shape prediction in a plane showed maximum errors of ~3.5 degrees (angular) and ~5.4 mm (linear).
• Spatial curvature tests yielded errors below 2.3 degrees.

Conclusions:

• The proposed optical fiber specklegram sensor offers a feasible and straightforward alternative to existing shape sensors.
• The system's simplicity and accuracy make it suitable for applications in medical devices and soft robotics.
• This method avoids complex processing, enhancing its practical applicability.