Multimode Magneto-Optical Fiber Based on Borogermanate Glass Containing Tb³⁺ for Sensing Applications.

Area of Science:

• Materials Science
• Optoelectronics
• Glass Science

Background:

• Developing rare-earth (RE) doped optical fibers with high Verdet constants for sensing applications faces challenges like precursor glass devitrification and poor optical quality.
• Silica-based fibers have limited Verdet constants, hindering their use in applications like Faraday rotators.

Purpose of the Study:

• To design, fabricate, and characterize a multimode magneto-optical fiber using Tb³⁺-containing borogermanate glass.
• To overcome devitrification issues in RE-doped glass precursors for improved optical fiber manufacturing.
• To assess the fiber's suitability for potential sensing applications by measuring its magneto-optical properties.

Main Methods:

• Fabrication of a core-cladding borogermanate fiber doped with Tb³⁺.
• Characterization using differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and viscosity measurements.
• Optical and magneto-optical property evaluation including M-lines spectroscopy, UV-Vis-NIR absorption, cut-back attenuation, and Verdet constant measurement.

Main Results:

• A multimode magneto-optical fiber with a 227 μm diameter was successfully fabricated.
• The fiber exhibited a numerical aperture (NA) of 0.183 and a minimum attenuation of 13 dB m^-1 at 1270 nm.
• A significant Verdet constant (V_B) of -6.74 rad T^-1 m^-1 was achieved at 1330 nm.

Conclusions:

• Borogermanate glass is a promising host for Tb³⁺ doping, enabling the fabrication of high-quality magneto-optical fibers.
• The developed fiber demonstrates potential for advanced sensing applications due to its high Verdet constant.
• This work addresses key challenges in RE-doped glass fiber production, paving the way for improved magneto-optical devices.