All-fiber absolute temperature sensor using an unbalanced high-birefringence Sagnac loop.

Area of Science:

• Fiber optics
• Optical sensing
• Photonics

Background:

• Fiber optic sensors offer remote and precise measurement capabilities.
• Sagnac loop interferometers are sensitive to environmental changes.
• High-birefringence fibers enable enhanced sensing performance.

Purpose of the Study:

• To demonstrate a highly sensitive temperature sensor.
• To utilize a stress-induced high-birefringence-fiber Sagnac loop.
• To employ a Nd-doped-fiber amplified spontaneous emission source for sensing.

Main Methods:

• Implementing a Sagnac loop with high-birefringence fiber.
• Utilizing spectral domain analysis for temperature detection.
• Measuring resonant wavelength shifts and resonance separation changes.

Main Results:

• Achieved a relative temperature sensitivity of approximately -0.94 x 10(-3)/K.
• Demonstrated a wavelength-shift sensitivity of -1.00 nm/K at 1.065 microm.
• Obtained a resonance separation sensitivity of 0.006 nm/K, with temperature accuracy better than 1 degree C.

Conclusions:

• The developed sensor exhibits high sensitivity and accuracy for temperature monitoring.
• The Sagnac loop configuration effectively translates temperature variations into measurable spectral changes.
• This telemetric sensor is suitable for precise temperature measurements over a broad operational bandwidth.