Widely tunable third-harmonic generation in a tellurite microstructured optical fiber

Area of Science:

• Materials Science
• Nonlinear Optics
• Optical Fiber Technology

Background:

• Microstructured optical fibers (MOFs) offer unique light-matter interaction properties.
• Tellurite glasses exhibit high nonlinear optical coefficients, making them promising for nonlinear applications.
• Third-harmonic generation (THG) is a key nonlinear optical process for frequency conversion.

Purpose of the Study:

• To design and fabricate a novel tellurite microstructured optical fiber (TMOF).
• To investigate widely tunable third-harmonic generation (THG) in the fabricated TMOF.
• To elucidate the underlying mechanism of THG in the TMOF.

Main Methods:

• Fabrication of a tellurite glass microstructured optical fiber (76.5TeO2-6Bi2O3-11.5Li2O-6ZnO, mol. %).
• Characterization of the TMOF's optical loss at 1550 nm (~0.2 dB/m).
• Pumping the TMOF with an optical parametric oscillator (OPO) across a wavelength range of 1700–2700 nm to achieve THG.

Main Results:

• Achieved widely tunable THG spanning from approximately 567 nm to 902 nm.
• Demonstrated efficient THG through high nonlinearity and high pump power, rather than phase-matching.
• Investigated the THG signal pattern to understand the generation mechanism.

Conclusions:

• The developed tellurite microstructured optical fiber is suitable for widely tunable nonlinear optical frequency conversion.
• The high nonlinearity and pump power are the dominant factors for THG in this TMOF.
• This work provides a new platform for exploring nonlinear optical phenomena in tellurite-based optical fibers.