LVF Catalog

Fluoride Glass Fibers

Fluoride glasses

Fluoride glasses

Learn more about our fluoride glass fibers specifications

Since the discovery of ZBLAN glasses in 1974, Le Verre Fluoré has worked to develop a large range of fluoride optical fibers, including ZrF4, InF3 and AlF3 based optical fibers, designed for mid-infrared applications.


Typical compositions for ZFG and IFG glasses are:

ZFG (Zirconium ZrF4 Fluoride Glass) = fluorozirconate fibers
53 ZrF4-20 BaF2-4 LaF3-3 AlF3-20 NaF

IFG (Indium InF3 Fluoride Glass) = fluoroindate fibers
40 InF3-20 ZnF2-20 SrF2-20 BaF2

They have the specificity to exhibit a high transparency from UV to mid-infrared : from 0.22 up to 7 µm and 0.255 up to 8 µm in case of ZFG and IFG (3 mm thick samples), respectively. (See figure below)

As a result, they totally cover the 3-5 µm atmospheric transparency window and partially covers the molecular fingerprinting region, paving the way to numerous passive and active applications.

Here are given some ZFG and IFG glass properties (see table) :

Glass transition temperature Tg (°C)
Density (
≈ 4.5
≈ 5.0
Refractive index nD
≈ 1.50-1.51
≈ 1.48-1.51
Non linear refractive index n2(x 10-20 m²/W)
≈ 2.1
≈ 3.2-4.3 [ref.]
Phonon energy (cm-1)
≈ 580
≈ 510

Below, the figure including arrows will enable you to appreciate fluoride properties compared to silica and chalcogenide glasses.