Single Mode Fluoride Glass Optical Fiber
- Single Mode ZBLAN or InF3 Fluoride Fiber Manufactured In-House
- Transmissive from the UV to Mid-IR
- Single Mode Operation Over 2.3 - 4.1 µm or 3.2 - 5.5 µm
- Stable in Typical Lab Environments and Easy to Handle
Fluoride Fiber Cross Section
(Not to Scale)
- Fiber Lasers
- Supercontinuum Light Sources
- Environmental Monitoring
- Surgical Lasers
- Chemical Sensing
- IR Imaging
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Compared to standard silica glass fibers, Thorlabs' single mode
fluoride fibers are transmissive at much longer wavelengths.
- Fluoride Glass Fibers Manufactured at Thorlabs' Fiber
- Fluorozirconate (ZBLAN)† for 285 nm - 4.1 µm
- Fluoroindate (InF3) for 310 nm - 5.5 µm
- Single Mode Wavelength Range:
- 2.3 µm - 4.1 µm for ZLBAN
- 3.2 µm - 5.5 µm for InF3
- World-Class Attenuation, Strength, and Geometry Control
- Custom Core Sizes and Cutoff Wavelengths Available by Contacting firstname.lastname@example.org
Thorlabs' single mode fluoride glass fibers are manufactured in-house and have world-class purity, precision, and strength. For more information about fluoride glass and our manufacturing process, see the Manufacturing tab and our main fluoride fiber web presentation.
Fluoride fibers offer low attenuation in the mid-IR wavelength range, aided by an extremely low hydroxyl ion (OH) content. Our IRZS23 fiber is made from ZBLAN† (fluorozirconate) glass and is highly transmissive over the 285 nm - 4.1 µm range, with single mode operation from 2.3 µm to 4.1 µm. Our IRFS32 fiber is made from InF3 (fluoroindate) glass, is highly transmissive over the 310 nm - 5.5 µm range, and exhibits single mode operation from 3.2 µm to 5.5 µm. The graph to the right shows how the wavelength-dependent attenuation compares to that of a standard silica glass fiber.
The refractive index of fluoride glass is near that of silica. As a result, optical fibers manufactured using fluoride glass exhibit low return losses and Fresnel reflections at both fiber-air and fiber-silica interfaces. Graphs of refractive index, numerical aperture (NA), and attenuation can be seen in the Graphs tab.
Since fluoride glass is softer than standard silica glass, extra care should be taken while cleaning and handling. See the Handling tab for suggested procedures.
Thorlabs also manufactures multimode fluoride fiber. See the selection guide below for links to the main web presentation for each type of component we offer.
† ZBLAN and ZrF4 are used interchangeably to refer to fluorozirconate glass.
Custom Fluoride Fiber
If our standard offerings do not meet your needs, please contact us to discuss customization and potential fiber draws. Some of the many customization options we provide for fluoride fibers include:
- Hand-Selected Extra-Low-Loss Fibers to Meet Strict Attenuation Requirements
- Custom Core and Cladding Geometries
- Dual-Polymer Claddings Available
- Increased Power Handling Capabilities
Fluoride Fibers and Components
This tab contains plots of the typical attenuation, bend-induced attenuation, mode field diameter, dispersion, numerical aperture, and core and cladding refractive indices of our single mode fluoride fibers as a function of wavelength. Variations in these properties can occur between fiber draws. Please contact Tech Sales to discuss whether these fibers are appropriate for your application.
These graphs show the typical measured attenuation of our single mode fluoride fibers. The red shaded regions denote the range of single mode operation with guaranteed attenuation for each fiber, while the blue shaded regions denote the range of single mode operation without guaranteed attenuation. The peak just below the single mode cutoff wavelength is caused by attenuation of the second-order mode.
This data was obtained by measuring the attenuation of a bend-free 1 m length of fiber, and comparing with the attenuation of the same length when a single loop with the given radius was added. These graphs show the additional attenuation introduced by the loop. The red shaded regions denote the range of single mode operation with guaranteed attenuation for each fiber, while the blue shaded regions denote the range of single mode operation without guaranteed attenuation.
Mode Field Diameter
These graphs show the typical mode field diameter of our single mode fluoride fibers, calculated from the measured core diameter and calculated numerical aperture of each fiber. The blue shaded regions denote the range of single mode operation for each fiber.
These graphs show the typical chromatic dispersion of our single mode fluoride fibers, calculated from the refractive indices. The blue shaded regions denote the range of single mode operation for each fiber.
These graphs show the typical numerical aperture (NA) of our single mode fluoride fibers, calculated from the core and cladding refractive indices. The blue shaded regions denote the range of single mode operation for each fiber.
These graphs show the typical refractive indices of the core and cladding of our single mode fluoride fibers. The graphed data was obtained by fitting the Sellmeier equation to measured data. The Sellmeier equation and best-fit parameters for each fiber's core and cladding can be seen below each graph. The blue shaded regions in the graphs denote the range of single mode operation for each fiber.
|ZBLAN Sellmeier Coefficients
|InF3 Sellmeier Coefficients
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This diagram compares on-axis tension, which can be safely applied, to off-axis tension, which can induce unsafe curvature and damage the fiber.
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The recommended procedure for removing tape from the bare fiber spools is shown in this image. The tape should be pulled parallel to the fiber when removing, while the other hand applies gentle force to stabilize the fiber.
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These images depict the recommended stripping procedure. A: Immerse the target fiber secion in stripping liquid.
B-C: Gently pinch the base of the soaked section with FSGT tweezers and pull toward the end of the fiber.
D: The coating should slide off, leaving a stripped section.
The material properties of fluoride glass differ from those of silica glass. This tab details recommended handling procedures for our fluoride fibers and patch cables.
Safety and Disposal
ZBLAN and InF3 glasses may present health risks. Information about the composition of our fluoride fibers is available from Tech Support upon request. When handling bare, stripped fluoride fiber, chemically resistant gloves such as our nitrile gloves should always be worn. Fiber shards generated from cleaving should be disposed of in a sharps container such as our FTDU fiber optic disposal unit.
Thorlabs will accept and dispose of any fluoride fiber or filled disposal units that you wish to discard. Please contact Tech Support before returning fiber or filled disposal units. If you wish to dispose of fiber locally, please follow all applicable local laws and regulations.
Because fluoride glass is softer than silica glass, exposed end faces are easily scratched during storage, and care should be taken to ensure that they are not exposed to mechanical abrasion. Storage under normal lab temperatures and humidities will not affect the integrity of the fiber. Prolonged, direct contact with liquid water or water vapor should be avoided.
Bending and Tension
Fluoride fiber is strong in tension, but can break easily if forces are applied off-axis or if it is bent to a small radius. These fibers should never be bent to smaller than their short-term bend radii. Moderate on-axis forces can be safely applied to the fiber, such as tension applied during spooling. The diagram to the right demonstrates safe on-axis tension and unsafe off-asix tension.
Our bare fluoride fibers ship on a spool, with their ends taped to the spool body. When removing the fiber, the tape should be pulled parallel to the fiber, as shown in the image to the top right.
For protection, our fluoride patch cables are jacketed with PVDF furcation tubing or stainless steel tubing that is stiffer than the jackets used in typical patch cables. As long as the jacket is not forced to bend below its specified minimum radius, the fiber will remain intact. For out patch cables with PVDF jackets, the tubing will become discolored if the bending limit is exceeded. Our patch cables with stainless steel tubing are designed so that the tubing mechanically limits the fiber to be unable to bend below its minimum radius.
Fluoride fibers are susceptible to damage when conventional mechanical stripping techniques are used, owing to the softness of the glass. Our FSGT Coating Stripping Tweezers can be used along with a chemical stripping agent to effectively strip these fibers without scratching or nicking the cladding.
To strip a fiber, the coating should first be exposed to a stripping liquid such as a paint stripper for three to five minutes. Placing the stripping liquid in a long vessel such as a syringe with a long tip is recommended to increase ease of application. If using a gel-type stripper, it can be applied manually to the exterior of the fiber. Note that the required soaking time will depend on the particuar stripping agent being used as well as the chemical composition of the coating. For example, if a dicholomethane (DCM) based stripping liquid is used, the required time may be shorter.
The coating on the section of the fiber soaked in stripping liquid will visibly swell, as seen in section B of the image to the right. A pair of FSGT tweezers can then be used to gently pinch the fiber in the soaked section, and pull toward the end of the fiber. Care should be taken to ensure that only moderate pressure is applied, or else the fiber may break. The soaked coating should slide off the end of the fiber, leaving the cladding exposed. If residue remains on the stripped section, it can be cleaned as detailed below.
Refer to any safety documentation for the chemical stripping agent before use.
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These images depict the recommended procedure for cleaning end faces with a solvent.
A: Wet a stack of five or mote TCW604 wipes with an appropriate solvent (see the text for examples).
B: Gently pass the fiber end face across the wet wipe.
Because fluoride glass is soft, end faces and stripped sections of our fluoride fibers and patch cables can be easily scratched during cleaning. If particulates are present on the glass surface, first try to remove them using compressed air. If compressed air is insufficient, then an appropriate solvent can be used with our TCW604 TechniCloth®† Lint-Free Wipes to clean the tip, as shown in the image to the left. Methanol and isopropanol are examples of appropriate solvents, while acetone is unsuitable. Wiping with a dry cloth is not recommended as it may scratch the surface.
Please note that Kimwipes®†† are extremely likely to scratch the fiber tip and should not be used.
Our fluoride fibers can be cleaved using a tension-and-scribe cleaver such as our Vytran® LDC401 large-diameter fiber cleaver. Note that cleaving these fibers may generate shards. Safety glasses and chemically resistant gloves should always be worn when cleaving.
†TechniCloth® is a registered trademark of the Illinois Tool Works, Inc. Corporation.
††Kimwipes® is a registered trademark of the Kimberly-Clark Corporation.
View our recorded webinar, in which we highlight our manufacturing techniques, the history of fluoride fiber R&D, and the state of fluoride fiber technology today and in the future.
Thorlabs manufactures ZBLAN zirconium fluoride (ZrF4) and indium fluoride (InF3) fibers at our vertically integrated fiber draw facility. The facility handles raw materials, glass preforms, fiber draw, and patch cable production, all in the same location. By controlling the process from start to finish, Thorlabs can ensure fibers consistently meet world-class specifications, including low attenuation, high mechanical strength, and precise geometry control.
The facility, located in Newton, NJ, USA, is well-equipped for high-volume manufacturing and is capable of producing many kilometers of fiber with consistent performance. In addition, because the fiber stays within Thorlabs' facilities from start to finish, the manufacturing process can be adjusted to accommodate unique custom orders or R&D needs.
Fluoride fibers are ideal for transmission in the mid-IR wavelength range, and Thorlabs' fibers feature low attenuation over this range as a result of stringent manufacturing processes yielding an extremely low hydroxyl ion (OH) content. Fluoride fibers also have lower refractive indices and lower chromatic dispersion when compared to other fibers that offer transmission in the mid-IR range, such as chalcogenide glass fibers. Thorlabs' tightly controlled processes mitigate scattering and point defects in the fiber, as well as eliminate micro-crystallization in the glass matrix.
Fluoride Fiber Characterization and Testing
In addition to manufacturing fiber, Thorlabs offers testing and characterization services for our fiber products. We precisely measure the properties of each drawn fiber to ensure that it meets our high standards of quality. Extensive testing also provides feedback for our fiber draw team, enabling tight control of each step in the manufacturing process. Customers can request custom testing of any Thorlabs-manufactured fiber, which is then provided with the shipped fiber. Testing of third-party fiber samples provided by customers is also available upon request.
Available tests and services include:
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A Thorlabs engineer mixes raw materials in our fluoride glass fabrication facility.
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A Glass Drop During the Fiber Draw Process
- Spectral Attenuation Measurement
- UV / Visible / NIR / MIR Wavelength Range
- SM or MM Fiber and Bulk Glass
- SM Fiber Cutoff Wavelength Measurement
- Fiber NA Measurement
- Fiber Glass / Coating Geometry Measurement
with Sub-µm Accuracy
- MIR High-Power Screening for MM Fibers
- Fiber Tensile Strength Testing
- Defect / Break Analysis
- Degree of Cure Testing for Fiber Coatings
Request testing for Thorlabs or third-party fibers by
contacting Tech Sales.
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These graphs show Thorlabs' steady improvement in the average attenuation of all fiber draws during the given year.
Thorlabs' team of MIR fiber researchers and engineers has many years of experience in fluoride glass research and development, production, and fiber draw. Their knowledge and expertise have resulted in consistent improvement in the quality of our fluoride fiber. See the graphs to the left for the progression of our fluoride fiber performance.
Custom Fluoride Fiber and Patch Cables
If our standard offerings do not meet your needs, please contact Tech Support to discuss customization and potential fiber draws. Some of the many customization options we provide for fluoride fibers and patch cables include:
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Thorlabs' Fiber Draw Tower
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The left image shows the intensity profile of the beam propagated through the fiber overlaid on the fiber itself. The right image shows the standard intensity profile of the beam propagated through the fiber with the MFD and core diameter called out.
Definition of the Mode Field Diameter
The mode field diameter (MFD) is one measure of the beam width of light propagating in a single mode fiber. It is a function of wavelength, core radius, and the refractive indices of the core and cladding. While much of the light in an optical fiber is trapped within the fiber core, a small fraction propagates in the cladding. The light can be approximated as a Gaussian power distribution as shown to the right, where the MFD is the diameter at which the optical power is reduced to 1/e2 from its peak level.
Measurement of MFD
The measurement of MFD is accomplished by the Variable Aperture Method in the Far Field (VAMFF). An aperture is placed in the far field of the fiber output, and the intensity is measured. As successively smaller apertures are placed in the beam, the intensity levels are measured for each aperture; the data can then be plotted as power vs. the sine of the aperture half-angle (or the numerical aperture for an SM fiber).
The MFD is then determined using Petermann's second definition, which is a mathematical model that does not assume a specific shape of power distribution. The MFD in the near field can be determined from this far-field measurement using the Hankel Transform.
Due to the fluoride fiber manufacturing process, Thorlabs is not able to guarantee the availability of long continuous fibers. If your order is for 20 m of fiber or more, you may be
shipped multiple shorter fibers, with a minimum length of 10 m each. If you require a longer continuous fiber, please contact email@example.com. Please note that orders for
a continuous length longer than 35 m will be subject to a surcharge.
Fibers with specific attenuation requirements, as well as bend radius proof testing, can also be requested. Please note that our fluoride fibers will typically ship within two days,
but special orders may be subject to longer lead times.