Fiber Optic Sensor Patent Technology

Fiber optic sensor patents cover a wide range of technologies, including current and voltage sensing, shape sensing, distributed sensing systems, and lossy-mode-resonance-based environmental sensors.

Key Patented Technologies

1. Fiber-Optic Current and Voltage Sensors Patents like US20160377660A1 describe fiber optic sensors that use a cross-coupling element between a polarizing element and a sensing fiber to measure electrical currents or magnetic fields. These sensors rely on the Faraday effect, where a magnetic field induces circular birefringence in the fiber, and the phase delay of light is proportional to the current, number of fiber windings, and the Verdet constant, which is temperature- and wavelength-dependent . Sagnac-type interferometers with quarter-wave retarders are also employed to enhance measurement accuracy. 2. Shape Sensing Fibers European patent EP3627112A1 covers optical fibers for shape sensing, which include multiple fiber cores with different refractive indices and radii to separate temperature-induced and strain-induced signals. These fibers allow real-time 3D reconstruction of devices like catheters or guide wires, enabling navigation without X-ray imaging. Fiber Bragg gratings (FBGs) are often embedded to provide precise reflection signals for curvature, torsion, and common-mode effects . 3. Distributed Sensor Systems Fiber SenSys LLC holds patents for spatially distributed sensor systems, where optical transmitters and conduits interact with sensing elements along the fiber. These systems can detect the position of a sensor along the fiber by analyzing returned light, and pulsed optical signals are used to reduce false alarms. Circuitous fiber paths with multiple bends create detection zones for intrusion or environmental monitoring . 4. Environmental and Chemical Sensing US11668873B2 describes fiber optic sensors with lossy-mode-resonance (LMR) coatings on polished fiber ends. These coatings, such as tin oxide (SnO2), allow detection of moisture or gaseous parameters by analyzing wavelength attenuation in the reflected signal. Such sensors are useful for monitoring environmental conditions or chemical reactions .

Applications and Advantages

• Electrical Measurement: High-voltage and high-current monitoring using Faraday-effect-based sensors.
• Medical Devices: Real-time shape sensing for minimally invasive procedures.
• Security and Structural Monitoring: Distributed sensing for intrusion detection or structural health monitoring.
• Environmental Monitoring: Detection of moisture, gases, or chemical changes using LMR-coated fibers. Fiber optic sensors are valued for their small size, immunity to electromagnetic interference, multiplexing capability, and remote sensing potential. Patents in this field often focus on improving accuracy, temperature compensation, signal processing, and multi-parameter sensing . These patents collectively illustrate the breadth of innovation in fiber optic sensing, spanning electrical, mechanical, environmental, and biomedical applications.