Dual-sensor technique for extending the dynamic range of a fiber-optic interferometric sensor

Area of Science:

• Optics and Photonics
• Sensor Technology
• Materials Science

Background:

• Fiber-optic sensors offer advantages in remote and harsh environment sensing.
• Achieving both high sensitivity and wide dynamic range in a single sensor remains a challenge.

Purpose of the Study:

• To develop a fiber-optic sensor system capable of simultaneously providing high sensitivity and a wide dynamic range.
• To demonstrate the effectiveness of using phase difference analysis for fringe order identification in interferometric sensors.

Main Methods:

• The sensor employs two fiber-optic interferometers with slightly different sensitivities.
• Phase difference between the outputs of the two interferometers is measured.
• A polarimetric temperature sensor is used as a demonstration, utilizing two different lengths of stress-induced birefringent fibers.

Main Results:

• The phase difference effectively disambiguates the fringe order from either interferometer.
• This method allows for accurate measurements across a broad range of conditions.
• Successful demonstration of a high-performance polarimetric temperature sensor.

Conclusions:

• The proposed dual-interferometer approach overcomes the limitations of single-interferometer systems.
• This technique enables the design of sensors with enhanced performance characteristics.
• The method is broadly applicable to various fiber-optic sensing applications requiring high sensitivity and wide dynamic range.