Bending-induced birefringence in single-mode fibers

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Optical fibers are crucial for modern communication.
• Bending optical fibers can alter their light-guiding properties.
• Internal stresses arise in bent fibers due to material deformation.

Purpose of the Study:

• To investigate the relationship between fiber bending and induced birefringence.
• To quantify the stress-induced birefringence in silica optical fibers.

Main Methods:

• Theoretical analysis of stress distribution in a bent optical fiber.
• Experimental measurement of birefringence at a specific wavelength (0.633 micrometers).

Main Results:

• Lateral internal stress in bent optical fibers induces birefringence (betab).
• The stress-induced birefringence in silica fibers was found to be betab = 7.7 x 10^7 r²/R² deg/m.
• The formula directly relates birefringence to fiber radius (r) and bending radius (R).

Conclusions:

• Fiber bending is a significant factor influencing optical fiber birefringence.
• The derived formula provides a quantitative tool for predicting birefringence in bent silica fibers.
• Understanding this phenomenon is vital for designing reliable optical fiber systems.