Mid-infrared supercontinuum generation in fluoroindate fiber

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Mid-infrared (MIR) supercontinuum generation is crucial for spectroscopy and sensing.
• Fluoride-based fibers offer potential for MIR applications due to low optical loss.
• Existing fiber technologies face limitations in spectral broadening and power handling.

Purpose of the Study:

• To demonstrate MIR supercontinuum generation in a novel step-index fluoroindate-based fiber.
• To evaluate the performance of fluoroindate fibers for MIR light propagation and spectral broadening.
• To compare the supercontinuum generation capabilities with established ZBLAN fibers.

Main Methods:

• Fabrication of a step-index fluoroindate-based fiber with a large core.
• Characterization of the fiber's optical properties, including dispersion and loss in the MIR region.
• Generation of MIR supercontinua using ultrashort laser pulses from an optical parametric amplifier.
• Spectral analysis of the generated supercontinuum, focusing on spectral flatness and bandwidth.

Main Results:

• The fluoroindate fiber successfully guided multiwatt laser power over a broad spectral range.
• The fiber exhibited zero dispersion at 1.83 μm and low loss (0.1-0.8 dB/m) from 3.2 to 5 μm.
• A 20 dB spectral flatness supercontinuum was generated from 2.7 to 4.7 μm.
• This represents twice the spectral broadening achieved with ZBLAN fiber under similar conditions.

Conclusions:

• Fluoroindate-based fibers are highly effective for MIR supercontinuum generation and low-loss propagation.
• The demonstrated spectral broadening significantly surpasses that of ZBLAN fibers.
• These findings highlight the potential of fluoroindate fibers for advanced MIR photonic applications.