Nonlinear resolution enhancement of an FBG based temperature sensor using the Kerr effect

Area of Science:

• Photonics and Optical Sensing
• Nonlinear Optics
• Fiber Optic Sensors

Background:

• Fiber Bragg Gratings (FBGs) are widely used in sensing applications.
• Enhancing the resolution of FBG-based sensors is crucial for precise measurements.
• All-optical signal processing offers potential for improved sensor performance.

Purpose of the Study:

• To demonstrate a novel all-optical signal processing technique for enhancing the resolution of fiber optical sensors.
• To investigate the application of the Kerr effect in nonlinear fibers for signal processing.
• To improve the distinguishability of central wavelength shifts in FBG-based sensors.

Main Methods:

• Generating an FBG reflection spectrum signal using a tunable laser.
• Launching the FBG signal and a fixed-frequency pump laser into a highly nonlinear fiber.
• Utilizing the Kerr effect to generate frequency sidebands and filtering specific orders (e.g., n=-4) to narrow the signal spectrum.

Main Results:

• Achieved a maximum resolution enhancement factor of 3.35 by extracting the n=-4 order sideband.
• Successfully applied the resolution enhancement technique to an FBG-based temperature sensor.
• Demonstrated that the potentiation effect reduces signal spectral width, improving wavelength shift detection.

Conclusions:

• The proposed all-optical signal processing method effectively enhances fiber optical sensor resolution.
• This technique offers a versatile approach applicable to existing fiber-based sensors and optical systems.
• The Kerr effect-induced sideband filtering provides a powerful tool for improving measurement precision in optical sensing.