Double-polarization interferometer for digital force sensing by fiber tension bending

Area of Science:

• Optoelectronics
• Fiber optic sensing
• Mechanical engineering

Background:

• Fiber-optic sensors offer high sensitivity and immunity to electromagnetic interference.
• Accurate force measurement is crucial in various engineering applications.
• Traditional fringe counting in interferometric sensors can suffer from ambiguity.

Purpose of the Study:

• To investigate a fiber-optic interferometric force sensor with digital readout.
• To eliminate ambiguity in fringe counting using a novel method.
• To establish and experimentally verify the relationship between transverse force and fiber strain.

Main Methods:

• Development of a fiber-optic interferometric sensor.
• Implementation of the double-polarization method to resolve fringe counting ambiguity.
• Measurement of transverse force (F(t)) by quantifying tension-bending-induced fiber strain.
• Derivation of a theoretical strain-force characteristic.

Main Results:

• Successful elimination of fringe counting ambiguity using the double-polarization technique.
• Experimental verification of the derived theoretical strain-force characteristic.
• Demonstration of an F(t)(2/3) dependence of fiber strain on the applied transverse force.

Conclusions:

• The developed fiber-optic sensor provides an unambiguous digital readout for transverse force measurement.
• The double-polarization method effectively addresses fringe counting ambiguity in interferometric systems.
• The sensor's performance is validated by the experimentally confirmed F(t)(2/3) strain-force relationship.