Optical phase fluctuations thermally induced in a single-mode optical fiber

Area of Science:

• Optics and Photonics
• Fiber Optics
• Thermal Physics

Background:

• Thermal fluctuations in optical fibers can impact signal integrity.
• Understanding these fluctuations is crucial for sensitive measurements.
• Single-mode optical fibers are widely used in telecommunications and sensing.

Purpose of the Study:

• To derive mathematical expressions for thermally induced optical phase and frequency fluctuations.
• To experimentally measure these fluctuations and compare them with theoretical predictions.
• To determine the minimum detectable temperature change using optical phase shifts.

Main Methods:

• Derivation of mathematical models for optical phase and frequency fluctuations.
• Mach-Zehnder interferometry for measuring optical phase and temperature fluctuations.
• Experimental validation against theoretical predictions at a wavelength of 0.6328 microm.

Main Results:

• Mathematical expressions were derived relating fluctuations to fiber length, thermal coherence length, and frequency.
• Experimental measurements of optical phase and temperature fluctuations showed good agreement with theory.
• A minimum detectable temperature change of 10(-5) K was achieved.

Conclusions:

• The derived mathematical expressions accurately describe thermal fluctuations in optical fibers.
• Mach-Zehnder interferometry is a viable method for measuring these phenomena.
• Laser frequency stability is critical for achieving high sensitivity in temperature measurements.