Products Home / Optical Fiber & Fiber Patch Cables / Fluoride Optical Fiber / Multimode Fluoride Fiber Optic Patch CablesMultimode Fluoride Fiber Optic Patch Cables
- Multimode ZBLAN or InF3 Fluoride Fiber Patch Cables Manufactured In-House
- Transmissive in the UV, Visible, NIR, and MIR
- SMA905 or FC/PC-Compatible Connectors
- 1 m or 2 m Long
MF13L1
Ø100 µm InF3
FC/PC and SMA905 Connectors
MZ41L1
Ø450 µm ZBLAN
SMA905 Connectors
Included Caps
Included Caps
Fluoride Fiber Cross Section
(Not to Scale)
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Applications
- Spectroscopy
- Fiber Lasers
- Supercontinuum Light Sources
- Environmental Monitoring
- Surgical Lasers
- Chemical Sensing
- IR Imaging
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Click for Raw Data
Compared to standard silica glass fibers, Thorlabs' multimode
fluoride fibers are transmissive at much longer wavelengths.
Features
- Patch Cables Using Fluoride Fibers Manufactured at Thorlabs' Fiber Draw Facility:
- Fluorozirconate (ZBLAN)† for 285 nm - 4.1 µm
- Fluoroindate (InF3) for 310 nm - 5.5 µm
- Core Sizes:
- Ø100 µm, Ø200 µm, Ø450 µm, or Ø600 µm
for ZBLAN - Ø100 µm or Ø200 µm for InF3
- Ø100 µm, Ø200 µm, Ø450 µm, or Ø600 µm
- Vacuum-Compatible and Antireflection (AR) Ø100 µm Core InF3 Cable Available
- Compatible with Visible-Wavelength Alignment Beams
- Used in Spectroscopy, Environmental Sensing, and Medicine
- Low Fresnel Reflectance Losses: <4% per Face
- AR Coating for Any Wavelength Available by Contacting Tech Support
Our multimode fluoride fiber patch cables are designed for low-loss transmission in the mid-IR spectral range. They incorporate Thorlabs' multimode fluoride optical fibers, which 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 or 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 fluorozirconate (ZBLAN)† fiber patch cables have a transmission range of 285 nm - 4.5 µm, while our fluoroindate (InF3) patch cables have a transmission range of 310 nm - 5.5 µm. The graph to the right shows how the wavelength-dependent attenuation compares to a fused silica fiber.
The ends of each cable are terminated using metal ferrule connectors that are compatible with either SMA905-terminated or FC/PC-terminated components; SMA905 to SMA905, FC/PC-compatible to FC/PC-compatible, and FC/PC-compatible to SMA905 configurations are available (see the FC Connectors tab for information on the FC/PC-compatible connectors). We also offer a vacuum-compatible Ø100 µm core InF3 patch cable that is usable down to 1 x 10-8 Torr and has SMA905 connectors. Each cable includes two protective caps that shield the ferrule ends from dust and other hazards. Replacement CAPF (plastic) and CAPFM (metal) caps for FC/PC-compatible cables or CAPM (rubber) and CAPSM (metal) caps for SMA905-terminated cables are available separately.
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. Compared to unterminated fiber, the maximum power that these cables can withstand is limited by the connectors.
Thorlabs also offers bare fluoride fiber, single mode patch cables, and other fluoride fiber components. See the selection guide below for links to the main web presentation for each type of component.
† ZBLAN and ZrF4 are used interchangeably to refer to fluorozirconate glass.
Custom Fluoride Patch Cables
If our standard offerings do not meet your needs, please contact us to discuss customization. Some of the many customization options we provide for fluoride patch cables include:
- Custom Options: Fiber Type, Length, Termination, and Tubing
- OEM Patch Cables: Designed for Application Requirements
- AR-Coated Patch Cables
- Ruggedized Cabling for Harsh Environments
| In-Stock Multimode Fiber Optic Patch Cable Selection Guide |
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| Silica (180 nm to 2.4 µm) |
| Fluoride (285 nm to 5.5 µm) |
Fluoride Fibers and Components |
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| Multimode ZBLAN Fiber Patch Cable Specifications | |||||||||
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| Item # Prefix | MZ11 | MZ12 | MZ13 | MZ21 | MZ22 | MZ41 | MZ42 | MZ61 | MZ62 |
| Connector Compatibilitya | SMA905 | FC/PC | FC/PC to SMA905 |
SMA905 | FC/PC | SMA905 | FC/PC | SMA905 | FC/PC |
| Jacket | FT030DF-B | Ø3.5 mm Stainless Steel |
Ø8.0 mm Stainless Steel |
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| Bare Fiber Item # | FZM10020 |
FZM20020 | FZM45020 | FZM60020 | |||||
| Transmission Rangeb | 285 nm - 4.5 µm | ||||||||
| Typical Attenuationc | 0.15 dB/m @ 2.5 µm | 0.2 dB/m @ 2.5 µm | |||||||
| Maximum Attenuationc | ≤0.2 dB/m (from 2.0 to 3.6 µm) |
≤0.25 dB/m (from 2.0 to 3.6 µm) |
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| NAd | 0.20 ± 0.02 @ 2.0 µm | ||||||||
| Typical Core Indexe | 1.495 @ 2.5 µm | ||||||||
| Core Diameter | 100 ± 7 µm | 200 ± 10 µm | 450 ± 15 µm | 600 ± 20 µm | |||||
| Cladding Diameter | 192 ± 2.5 µm | 290 ± 10 µm | 540 ± 15 µm | 690 ± 20 µm | |||||
| Coating Diameter | 275 ± 25 µm | 430 ± 25 µm | 650 ± 25 µm | 800 ± 40 µm | |||||
| Core/Cladding Concentricity | ≤2.5 µm | ≤3.0 µm | ≤5.0 µm | ≤10.0 µm | |||||
| Core Circularity | ≥95% | ≥95% | ≥95% | ≥95% | |||||
| Long-Term Bend Radiusf | ≥50 mm | ≥80 mm | ≥125 mm | ≥160 mm | |||||
| Short-Term Bend Radius | ≥29 mmg | ≥40 mm | ≥50 mmh | ≥140 mmh | |||||
| Operating Temperature | -40 to 85 °C | -55 to 90 °C | |||||||
| Bare Fiber End Face Imagei (Click for Scale) |
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| Multimode InF3 Fiber Patch Cable Specifications | |||||||
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| Item # Prefix | MF11 | MF12 | MF13 | MFV1 | MF11L1AR1 | MF21 | MF22 |
| Connector Compatibilitya | SMA905 | FC/PC | FC/PC to SMA905 |
SMA905 | SMA905 | FC/PC | |
| Jacket | FT030DF-B | Ø5.2 mm Stainless Steel |
FT030DF-B | FT030DF-B | |||
| Bare Fiber Item # | FFM10026 | FFH10026 | FFM20026 | ||||
| Transmission Rangeb | 310 nm - 5.5 µm | ||||||
| Typical Attenuationc | 0.1 dB/m @ 2.5 µm and 3.6 µm | 0.08 dB/m @ 2.5 µm and 3.6 µm | 0.1 dB/m @ 2.5 µm and 3.6 µm | ||||
| Maximum Attenuationc | ≤0.25 dB/m (from 2.0 to 4.6 µm) |
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| NAd | 0.26 ± 0.02 @ 2 µm | ||||||
| Typical Core Indexe | 1.487 @ 3.6 µm | ||||||
| Core Diameter | 100 ± 2.0 µm | 200 ± 10 µm | |||||
| Cladding Diameter | 192 ± 2.5 µm | 290 ± 10 µm | |||||
| Coating Diameter | 280 ± 15 µm | 287 ± 15 µm | 430 ± 25 µm | ||||
| Core/Cladding Concentricity | ≤2.0 µm | ≤3.0 µm | |||||
| Core Circularity | ≥95% | ≥98% | ≥95% | ||||
| Long-Term Bend Radiusf | ≥50 mm | ≥80 mm | |||||
| Short-Term Bend Radius | ≥29 mmg | ≥50 mmh | ≥25 mm | ≥40 mm | |||
| Operating Temperature | -40 to 85 °C | -55 to 75 °C | -40 to 85 °C | -40 to 85 °C | |||
| Bare Fiber End Face Imagei (Click for Scale) |
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This tab contains plots of the typical attenuation, numerical aperture, and core and cladding refractive indices of the multimode fluoride fibers that are used in our patch cables. Variations in these properties can occur between fiber draws. Please contact Tech Sales to discuss whether these patch cables are appropriate for your application.
Attenuation
These graphs show measured attenuation of our multimode fluoride fibers, from several independent fiber runs. The blue shaded regions denote the wavelength range with guaranteed attenuation performance for each fiber, which is represented by the dashed line.
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This data was taken from five independent runs of Ø450 μm core ZBLAN fiber, and is representative of all ZBLAN fibers with cores from Ø50 μm to Ø450 μm.
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This data was taken from four independent runs of Ø100 μm core InF3 fiber.
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This data was taken from five independent runs of Ø600 μm core ZBLAN fiber.
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This data was taken from five independent runs of Ø200 μm core InF3 fiber.
Numerical Aperture
These graphs show the typical numerical aperture (NA) of our multimode fluoride fibers, calculated from the core and cladding refractive indices.
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Refractive Indices
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.
Sellmeier Equation
| ZBLAN Sellmeier Coefficients | ||
|---|---|---|
| Coefficient | Core | Cladding |
| u0 | 0.5463 | 0.705674 |
| u1 | 0.7566 | 0.515736 |
| u2 | 1.782 | 2.204519 |
| u3 | 0.000 | 0.087503 |
| u4 | 0.116 | 0.087505 |
| u5 | 21.263 | 23.80739 |
| A | 0.9562 | 1 |
| InF3 Sellmeier Coefficients | ||
|---|---|---|
| Coefficient | Core | Cladding |
| u0 | 0.47627338 | 0.68462594 |
| u1 | 0.76936893 | 0.4952746 |
| u2 | 5.01835497 | 1.4841315 |
| u3 | 0.0179549 | 0.0680833 |
| u4 | 0.11865093 | 0.11054856 |
| u5 | 43.64545759 | 24.4391868 |
| A | 1 | 1 |
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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.
Storage
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.
Stripping
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 more TCW604 wipes with an appropriate solvent (see the text for examples).
B: Gently pass the fiber end face across the wet wipe.
Cleaning
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.
Cleaving
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.
FC-Terminated Fluoride Patch Cables have Flat-Polished Tips
Standard FC/PC Connectors have Domed Tips
When using standard silica fiber patch cables, FC/PC or FC/APC connectors are typically chosen because the PC and APC polishes provide domed tips that bring the cores of two mated patch cables into physical contact. This physical contact minimizes the connection loss at the cable-to-cable interface.
Since fluoride glass is softer than silica glass, the polishing procedures used for silica glass result in flat fiber tips. Depending upon the cable, the tip may also be slightly recessed with respect to the ferrule. Fluoride patch cable connectors are therefore neither FC/PC (where "PC" denotes Physical Contact) nor FC/APC (where "APC" denotes Angled Physical Contact). Hence, we denote these cables as either flat-polished FC or angle-polished FC.
The flat fiber tip does not affect applications where the fiber output is being coupled into free space. However, when making cable-to-cable connections with FC connectors, such as through a mating sleeve or a bulkhead, transmission losses can occur because the fiber cores may not be in physical contact. Because the gap between FC-terminated cables is smaller than the typical gap between SMA905-terminated cables (which use air-gap ferrules), these losses are usually negligible.
The images below show two- and three-dimensional representations of the tip of a finished fluoride patch cable.
True domed-top FC connectors are available with these fluoride fibers as a custom order. Please contach Tech Sales for more information.
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This image contains a two-dimensional surface profile of the tip of a Ø100 µm core, flat-polished FC fluoride patch cable. The X and Y axis units are displayed in microns. The dashed circles and lines are shown as a guide to the eye. The interface between the metal ferrule and the cable interior is visualized by a faint green circle inside the blue dashed circle. This data is representative of all our flat-polished FC fluoride fiber patch cables.
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This image contains a three-dimensional map of the tip of a Ø100 µm core, flat-polished FC fluoride patch cable. The dashed circles are shown as a guide to the eye. The interface between the metal ferrule and the cable interior is represented by the round depression between the black and blue circles. This data is representative of all our flat-polished FC fluoride fiber patch cables.
Thanks to their operation in the mid-IR wavelength range, these multimode fluoride fiber patch cables are ideal for a variety of applications that are unsuitable for silica fibers. Such applications include mid-IR spectroscopy, chemical sensing, and environmental monitoring, as well as mid-IR fiber lasers and supercontinuum light sources.
Mid-IR Applications
Because of their wide transmission range and flat attenuation, these patch cables are ideal for our Quantum Cascade Lasers (QCLs) and Interband Cascade Lasers (ICLs), which offer either broadband or single-wavelength emission in the MIR range. Because fluoride glass transmits down into the UV, visible light (such as that generated by fiber-coupled lasers) can be propagated along the same fiber as an alignment aid.
These fibers are also well matched to our SLS202La Stabilized Light Source, which provides a blackbody radiation spectrum that spans from the visible into the mid-IR. Our Ø100 µm core patch cables are recommended for use with our Optical Spectrum Analyzers. Other application examples are shown in the photos below.
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Fluoride patch cables can be connected to our MIR photodetectors using fiber adapters.
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The 310 nm - 5.5 µm wavelength range of InF3 patch cables makes them ideal for illumination applications that use our Stabilized Light Sources.
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In this setup, a ZrF4 patch cable is used to propagate mid-IR light into a sample chamber for gas-phase spectroscopy. (More information on the pictured setup is available here.)
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Total Internal Reflection in an Optical Fiber
Guiding Light in an Optical Fiber
Optical fibers are part of a broader class of optical components known as waveguides that utilize total internal reflection (TIR) in order to confine and guide light within a solid or liquid structure. Optical fibers, in particular, are used in numerous applications; common examples include telecommunications, spectroscopy, illumination, and sensors.
One of the more common glass (silica) optical fibers uses a structure known as a step-index fiber, which is shown in the image to the right. Step-index fibers have an inner core made from a material with a refractive index that is higher than the surrounding cladding layer. Within the fiber, a critical angle of incidence exists such that light will reflect off the core/cladding interface rather than refract into the surrounding medium. To fulfill the conditions for TIR in the fiber, the angle of incidence of light launched into the fiber must be less than a certain angle, which is defined as the acceptance angle, θacc. Snell's law can be used to calculate this angle:
where ncore is the refractive index of the fiber core, nclad is the refractive index of the fiber cladding, n is the refractive index of the outside medium, θcrit is the critical angle, and θacc is the acceptance half-angle of the fiber. The numerical aperture (NA) is a dimensionless quantity used by fiber manufacturers to specify the acceptance angle of an optical fiber and is defined as:
In step-index fibers with a large core (multimode), the NA can be calculated directly using this equation. The NA can also be determined experimentally by tracing the far-field beam profile and measuring the angle between the center of the beam and the point at which the beam intensity is 5% of the maximum; however, calculating the NA directly provides the most accurate value.
Number of Modes in an Optical Fiber
Each potential path that light propagates through in an optical fiber is known as a guided mode of the fiber. Depending on the physical dimensions of the core/cladding regions, refractive index, and wavelength, anything from one to thousands of modes can be supported within a single optical fiber. The two most commonly manufactured variants are single mode fiber (which supports a single guided mode) and multimode fiber (which supports a large number of guided modes). In a multimode fiber, lower-order modes tend to confine light spatially in the core of the fiber; higher-order modes, on the other hand, tend to confine light spatially near the core/cladding interface.
Using a few simple calculations, it is possible to estimate the number of modes (single mode or multimode) supported by an optical fiber. The normalized optical frequency, also known as the V-number, is a dimensionless quantity that is proportional to the free space optical frequency but is normalized to guiding properties of an optical fiber. The V-number is defined as:
where V is the normalized frequency (V-number), a is the fiber core radius, and λ is the free space wavelength. Multimode fibers have very large V-numbers; for example, a Ø50 µm core, 0.39 NA multimode fiber at a wavelength of 1.5 µm has a V-number of 40.8.
For multimode fiber, which has a large V-number, the number of modes supported is approximated using the following relationship.
In the example above of the Ø50 µm core, 0.39 NA multimode fiber, it supports approximately 832 different guided modes that can all travel simultaneously through the fiber.
Single mode fibers are defined with a V-number cut-off of V < 2.405, which represents the point at which light is coupled only into the fiber's fundamental mode. To meet this condition, a single mode fiber has a much smaller core size and NA compared to a multimode fiber at the same wavelength. One example of this, SMF-28 Ultra single mode fiber, has a nominal NA of 0.14 and an Ø8.2 µm core at 1550 nm, which results in a V-number of 2.404.
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Attenuation Due to Macrobend Loss
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Attenuation Due to Microbend Loss
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Beam profile measurement of FT200EMT multimode fiber and a former generation M565F1 LED (replaced by the M565F3) showing light guided in the cladding rather than the core of the fiber.
Sources of Attenuation
Loss within an optical fiber, also referred to as attenuation, is characterized and quantified in order to predict the total transmitted power lost within a fiber optic setup. The sources of these losses are typically wavelength dependent and range from the material used in the fiber itself to bending of the fiber. Common sources of attenuation are detailed below:
Absorption
Because light in a standard optical fiber is guided via a solid material, there are losses due to absorption as light propagates through the fiber. Standard fibers are manufactured using fused silica and are optimized for transmission from 1300 nm to 1550 nm. At longer wavelengths (>2000 nm), multi-phonon interactions in fused silica cause significant absorption. Fluoride glasses such as ZrF4 and InF3 are used in manufacturing Mid-IR optical fibers primarily because they exhibit lower loss at these wavelengths. ZrF4 and InF3 fibers have a multi-phonon edge of ~3.6 µm and ~4.6 µm, respectively.
Contaminants in the fiber also contribute to the absorption loss. One example of an undesired impurity is water molecules that are trapped in the glass of the optical fiber, which will absorb light around 1300 nm and 2.94 µm. Since telecom signals and some lasers operate in that same region, any water molecules present in the fiber will attenuate the signal significantly.
The concentration of ions in the fiber glass is often controlled by manufacturers to tune the transmission/attenuation properties of a fiber. For example, hydroxyl ions (OH-) are naturally present in silica and absorb light in the NIR-IR spectrum. Therefore, fibers with low-OH content are preferred for transmission at telecom wavelengths. On the other hand, fibers with high-OH content typically exhibit increased transmission at UV wavelengths and thus may be preferred by users interested in applications such as fluorescence or UV-VIS spectroscopy.
Scattering
For the majority of fiber optics applications, light scattering is a source of loss that occurs when light encounters a change in the refractive index of the medium. These changes can be extrinsic, caused by impurities, particulates, or bubbles; or intrinsic, caused by fluctuations in the glass density, composition, or phase state. Scattering is inversely related to the wavelength of light, so scattering loss becomes significant at shorter wavelengths such as the UV or blue regions of the spectrum. Using proper fiber cleaning, handling, and storage procedures may minimize the presence of impurities on tips of fibers that cause large scattering losses.
Bending Loss
Losses that occur due to changes in the external and internal geometry of an optical fiber are known as bending loss. These are usually separated into two categories: macrobending loss and microbending loss.
Macrobend loss is typically associated with the physical bending of an optical fiber; for example, rolling it in a tight coil. As shown in the image to the right, guided light is spatially distributed within the core and cladding regions of the fiber. When a fiber is bent at a radius, light near the outer radius of the bend cannot maintain the same spatial mode profile without exceeding the speed of light. Instead, the energy is lost to the surroundings as radiation. For a large bend radius, the losses associated with bending are small; however, at bend radii smaller than the recommended bend radius of a fiber, bend losses become very significant. For short periods of time, optical fibers can be operated at a small bend radius; however, for long-term storage, the bend radius should be larger than the recommended value. Use proper storage conditions (temperature and bend radius) to reduce the likelihood of permanently damaging the fiber; the FSR1 Fiber Storage Reel is designed to minimize high bend loss.
Microbend loss arises from changes in the internal geometry of the fiber, particularly the core and cladding layers. These random variations (i.e., bumps) in the fiber structure disturb the conditions needed for total internal reflection, causing propagating light to couple into a non-propagating mode that leaks from the fiber (see the image to the right for details). Unlike macrobend loss, which is controlled by the bend radius, microbend loss occurs due to permanent defects in the fiber that are created during fiber manufacturing.
Cladding Modes
While most light in a multimode fiber is guided via TIR within the core of the fiber, higher-order modes that guide light within both the core and cladding layer, because of TIR at the cladding and coating/buffer interface, can also exist. This results in what is known as a cladding mode. An example of this can be seen in the beam profile measurement to the right, which shows cladding modes with a higher intensity in the cladding than in the core of the fiber. These modes can be non-propagating (i.e., they do not fulfill the conditions for TIR) or they can propagate over a significant length of fiber. Because cladding modes are typically higher-order, they are a source of loss in the presence of fiber bending and microbending defects. Cladding modes are also lost when connecting two fibers via connectors as they cannot be easily coupled between optical fibers.
Cladding modes may be undesired for some applications (e.g., launching into free space) because of their effect on the beam spatial profile. Over long fiber lengths, these modes will naturally attenuate. For short fiber lengths (<10 m), one method for removing cladding modes from a fiber is to use a mandrel wrap at a radius that removes cladding modes while keeping the desired propagating modes.
Launch Conditions
Underfilled Launch Condition
For a large multimode fiber which accepts light over a wide NA, the condition of the light (e.g., source type, beam diameter, NA) coupled into the fiber can have a significant effect on performance. An underfilled launch condition occurs when the beam diameter and NA of light at the coupling interface are smaller than the core diameter and NA of the fiber. A common example of this is launching a laser source into a large multimode fiber. As seen in the diagram and beam profile measurement below, underfilled launches tend to concentrate light spatially in the center of the fiber, filling lower-order modes preferentially over higher-order modes. As a result, they are less sensitive to macrobend losses and do not have cladding modes. The measured insertion loss for an underfilled launch tends to be lower than typical, with a higher power density in the core of the fiber.
Overfilled Launch Condition
Overfilled launches are defined by situations where the beam diameter and NA at the coupling interface are larger than the core diameter and NA of the fiber. One method to achieve this is by launching light from an LED source into a small multimode fiber. An overfilled launch completely exposes the fiber core and some of the cladding to light, enabling the filling of lower- and higher-order modes equally (as seen in the images below) and increasing the likelihood of coupling into cladding modes of the fiber. This increased percentage of higher-order modes means that overfilled fibers are more sensitive to bending loss. The measured insertion loss for an overfilled launch tends to be higher than typical, but results in an overall higher output power compared to an underfilled fiber launch.
There are advantages and disadvantages to underfilled or overfilled launch conditions, depending on the needs of the intended application. For measuring the baseline performance of a multimode fiber, Thorlabs recommends using a launch condition where the beam diameter is 70-80% of the fiber core diameter. Over short distances, an overfilled fiber has more output power; however, over long distances (>10 - 20 m) the higher-order modes that more susceptible to attenuation will disappear.
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 Characteristics
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:
Click to Enlarge
A Thorlabs engineer mixes raw materials in our fluoride glass fabrication facility.
Click to Enlarge
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.
Click to Enlarge
These graphs show Thorlabs' steady improvement in the average attenuation of all fiber draws during the given year.
Technical Team
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:
Bare Fiber
|
Patch Cables
|
Click to Enlarge
Thorlabs' Fiber Draw Tower
| Posted Comments: | |
Jaya Sagar
(posted 2023-10-16 15:26:00.15) Hi, can you do this for a single mode fibre as well.
We need a vacuum compatible FC/PC patch cable single mode fibre for 785nm, 1m length. cdolbashian
(posted 2023-10-27 08:56:44.0) Thank you for reaching out to us with this inquiry. Unfortunately FC/PC connectors are not vacuum compatible. I have contacted you directly to discuss alternative options. Amirul Hasan
(posted 2023-05-26 18:37:53.113) Dear THORLABS,
I am looking for a multimode optical fiber of 3-5 meters in length, a core made of InF3 and size of 600 microns, and transmission in the wavelength band 2-5.2 microns.
Can you kindly let me know if it is available at the THORLAB?
Thank you
Amirul
Email id: amirul.itcc@iiap.res.in
Indian Institute of Astrophysics Bangalore cdolbashian
(posted 2023-06-01 04:03:42.0) Thank you for reaching out to us with this inquiry. At the time of posting this, we can only make up to 200um diameter InF3 fiber. I have reached out to you to discuss your application and potential alternatives. user
(posted 2021-03-11 12:01:48.627) Could I get the raw transmission(%/m) data of MF22L1? Its only uploaded about attenuation. YLohia
(posted 2021-03-12 03:39:17.0) The attenuation data can be converted to transmission data using the following calculation: 10^(-[insert dB/meter here]/10) * 100[to convert to %] = %/m Simon Hicks
(posted 2020-11-30 09:54:46.283) Hi, I need the bandwidth of the InF3 fibers, but they only seem to come with core diameters of 100 or 200um. Can you supply them with core diameters of 400 or 600um?
Thanks YLohia
(posted 2020-12-01 10:29:51.0) Thank you for contacting Thorlabs. Custom versions of these can be requested by emailing techsupport@thorlabs.com. We will discuss the possibility of offering this customization directly. michael.vollero
(posted 2018-11-28 14:57:41.78) What is the reason that the InF3 patch cables are only rated up to 90 degC? nbayconich
(posted 2018-12-04 02:58:40.0) Thank you for contacting Thorlabs. The temperature limitation of the patch cables will be limited by the furcation tubing, epoxy and connector ends. The bare InF3 fiber itself will typically have a lower operating temperature than bare silica fiber. I will reach out to you directly with more information. tarabrinmike
(posted 2018-08-13 15:31:05.613) Hello, how it's possible to launch over 2 W of MIR radiation of laser into fluoride fiber if connectors can handle only 300 mW? In that case core diameter doesn't matter YLohia
(posted 2018-08-13 04:11:04.0) Hello, unfortunately, it is not recommended to couple 2 Watts of power into connectorized fiber patch cables. We recommend cutting off the connector for high power coupling in this case. alan.marchant
(posted 2017-07-17 12:27:43.277) I'm confused by the bend curvature specifications. The minimum long-term bend radius for the 100 um core fibers are specified at 155 mm, much larger than for the 200 um core fibers (80 mm), defying intuition. Can you confirm or correct these values? To select the best fiber for my application, I need confidence in this specifications. tfrisch
(posted 2017-08-11 10:47:49.0) Hello, thank you for contacting Thorlabs. We are working on updating the bend radius specs since our initial values were quite conservative. 200um is the first to be corrected, and others will be listed as we gather data. patrick.nau
(posted 2014-10-31 15:56:57.697) Hi,
I want to use this fiber in combination with a DFB diode lase. Are these fibers also available with a FC/APC connector to reduce optical feedback?
Thank you very much jlow
(posted 2014-11-03 03:51:19.0) Response from Jeremy at Thorlabs: We do not have the FC/APC connector available for these multimode fiber because of the cladding size. However, we do have the angle polished FC available for single mode MIR fiber at https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_ID=7999. |
Zoom
Click for Details
Each fluoride patch cable is labeled with its
item #, key specifications, and batch number.
- Patch Cables Made from Thorlabs' Ø100 µm Core Multimode ZBLAN Fiber Manufactured In-House
- SMA905 or FC/PC-Compatible Connectors with Metal Ferrules
- 1 m or 2 m Long (Custom Lengths Available by Contacting Tech Sales)
- Stiff, Ø3.0 mm PVDF Furcation Tubing
- Two Protective Caps Included
- SMA905 Connectors: Stainless Steel Caps
- FC/PC Connectors: Plastic Caps
| Item # Prefixa |
Fiber | Transmission Rangeb |
Typical Attenuation |
Maximum Attenuation |
Core Diameter |
Cladding Diameter |
NAc | Bend Radius (Short Term/ Long Term) |
Connectors | Jacket | Operating Temperature |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MZ11 | FZM10020 | 285 nm - 4.5 µm | 0.15 dB/m @ 2.5 µm |
≤0.2 dB/m (for 2.0 - 3.6 µm) |
100 ± 7 µm | 192 ± 2.5 µm | 0.20 ± 0.02 @ 2.0 µm |
≥29 mmd / ≥50 mm | SMA905 | Blue PVDF (Ø3 mm) |
-40 to 85 °C |
| MZ12 | FC/PC-Compatiblee | ||||||||||
| MZ13 | FC/PC-Compatiblee to SMA905 |
Zoom
Click for Details
Each fluoride patch cable is labeled with its item #, key specifications, and batch number.
- Patch Cables Made from Thorlabs' Ø200 µm Core Multimode ZBLAN Fiber Manufactured In-House
- SMA905 or FC/PC-Compatible Connectors with Metal Ferrules
- 1 m or 2 m Long (Custom Lengths Available by Contacting Tech Sales)
- Stiff, Ø3.0 mm PVDF Furcation Tubing
- Two Protective Caps Included
- SMA905 Connectors: Stainless Steel Caps
- FC/PC Connectors: Plastic Caps
| Item # Prefixa |
Fiber | Transmission Rangeb |
Typical Attenuation |
Maximum Attenuation |
Core Diameter |
Cladding Diameter |
NAc | Bend Radius (Short Term/ Long Term) |
Connectors | Jacket | Operating Temperature |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MZ21 | FZM20020 | 285 nm - 4.5 µm | 0.15 dB/m @ 2.5 µm |
≤0.2 dB/m (for 2.0 - 3.6 µm) |
200 ± 10 µm | 290 ± 10 µm | 0.20 ± 0.02 @ 2.0 µm |
≥40 mm / ≥80 mm | SMA905 | Blue PVDF (Ø3 mm) |
-40 to 85 °C |
| MZ22 | FC/PC-Compatibled |
Zoom
Click for Details
Bottom View of Fiber End
Click for Details
Top View of Fiber End
Each fluoride patch cable is engraved with its item # and key specifications. The batch number is given on a separate white sleeve.
- Patch Cables Made from Thorlabs' Ø450 µm Core Multimode ZBLAN Fiber Manufactured In-House
- SMA905 or FC/PC-Compatible Connectors with Metal Ferrules
- 1 m Long (Custom Lengths Available by Contacting Tech Sales)
- Ø3.8 mm Stainless Steel Jacket with Minimum Bend Radius of 50 mm
- Two Protective Caps Included
- SMA905 Connectors: Stainless Steel Caps
- FC/PC Connectors: Plastic Caps
| Item #a | Fiber | Transmission Rangeb |
Typical Attenuation |
Maximum Attenuation |
Core Diameter |
Cladding Diameter |
NAc | Bend Radius (Short Term/ Long Term) |
Connectors | Jacket | Operating Temperature |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MZ41L1 | FZM45020 | 285 nm - 4.5 µm | 0.15 dB/m @ 2.5 µm |
≤0.2 dB/m (for 2.0 - 3.6 µm) |
450 ± 15 µm | 540 ± 15 µm | 0.20 ± 0.02 @ 2.0 µm |
≥50 mmd / ≥125 mm |
SMA905 | Stainless Steel (Ø3.8 mm) |
-55 to 90 °C |
| MZ42L1 | FC/PC-Compatiblee |
Zoom
Click for Details
Bottom View of Fiber End
Click for Details
Top View of Fiber End
Each fluoride patch cable is engraved with its item # and key specifications. The batch number is given on a separate white sleeve (not shown).
- Patch Cables Made from Thorlabs' Ø600 µm Core Multimode ZBLAN Fiber Manufactured In-House
- SMA905 or FC/PC-Compatible Connectors with Metal Ferrules
- 1 m Long (Custom Lengths Available by Contacting Tech Sales)
- Ø8.0 mm Stainless Steel Jacket with Minimum Bend Radius of 140 mm
- Two Protective Caps Included
- SMA905 Connectors: Stainless Steel Caps
- FC/PC Connectors: Plastic Caps
| Item #a | Fiber | Transmission Rangeb |
Typical Attenuation |
Maximum Attenuation |
Core Diameter |
Cladding Diameter |
NAc | Bend Radius (Short Term/ Long Term) |
Connectors | Jacket | Operating Temperature |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MZ61L1 | FZM60020 | 285 nm - 4.5 µm | 0.2 dB/m @ 2.5 µm |
≤0.25 dB/m (for 2.0 - 3.6 µm) |
600 ± 20 µm | 690 ± 20 µm | 0.20 ± 0.02 @ 2.0 µm |
≥140 mmd / ≥160 mm |
SMA905 | Stainless Steel (Ø8.0 mm) |
-55 to 90 °C |
| MZ62L1 | FC/PC-Compatiblee |
Zoom
Click for Details
Each fluoride patch cable is labeled with its item #, key specifications, and batch number.
- Patch Cables Made from Thorlabs' Ø100 µm Core Multimode InF3 Fiber Manufactured In-House
- SMA905 or FC/PC-Compatible Connectors with Metal Ferrules
- Stocked in 1 m and 2 m Lengths
- Custom Lengths Available by Contacting Tech Support
- Stiff, Ø3.0 mm Plastic Jacket
- Two Protective Caps Included
- SMA905-Terminated Cables: Stainless Steel Caps
- FC/PC-Compatible Cables: Plastic Caps
| Item # Prefixa |
Fiber | Transmission Rangeb |
Typical Attenuation |
Maximum Attenuation |
Core Diameter |
Cladding Diameter |
NAc | Bend Radius (Short Term/ Long Term) |
Connectors | Jacket | Operating Temp. |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MF11 | FFM10026 | 310 nm - 5.5 µm | 0.1 dB/m @ 2.5 µm and 3.6 µm |
≤0.25 dB/m (for 2.0 - 4.6 µm) |
100 ± 2.0 µm | 192 ± 2.5 µm | 0.26 ± 0.02 @ 2.0 µm |
≥29 mmd / ≥50 mm | SMA905 | Blue PVDF (Ø3 mm) |
-40 to 85 °C |
| MF12 | FC/PC-Compatiblee | ||||||||||
| MF13 | FC/PC-Compatiblee to SMA905 |
Zoom
Click to Enlarge
Bottom View of MFV1L1 Fiber End
Click to Enlarge
Top View of MFV1L1 Fiber End
Each fluoride patch cable is engraved with its item # and key specifications. The batch number is given on a separate white sleeve.
- Made from Thorlabs' Ø100 µm Core Multimode InF3 Fiber Manufactured In-House
- Hermetically Sealed Multimode Step-Index Fiber
- Construction Enables use at Vacuum Pressures Down to
1 x 10-8 Torr - SMA905 Connectors with Metal Ferrules
- Stocked in 1 m Lengths
- Ø5.2 mm 304 Stainless Steel Jacket
- Two Protective Caps Included
To complement the MFV1L1 patch cable, we also offer a KF40 flange fiber feedthrough that uses Ø100 µm InF3 multimode fiber (Item # VK4F1S). The two can be mated using a vacuum-compatible SMA mating sleeve, such as the ADASMAV.
| Item #a | Fiber | Transmission Rangeb |
Typical Attenuation |
Maximum Attenuation |
Core Diameter |
Cladding Diameter |
NAc | Bend Radius (Short Term/ Long Term) |
Connectors | Jacket | Temp. Rating |
Temp. Ramp |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MFV1L1 | FFH10026d | 310 nm - 5.5 µm | 0.08 dB/m @ 2.5 µm and 3.6 µm |
≤0.25 dB/m (for 2.0 - 4.6 µm) |
100 ± 2.0 µm | 192 ± 2.5 µm | 0.26 ± 0.02 @ 2.0 µm |
≥50 mme / ≥50 mm |
SMA905 | Ø5.2 mm Stainless Steel Interlock Tubing |
90 °Cf 75 °Ce |
10 °C / minute (Max) |
Zoom
Click to Enlarge
Each fluoride patch cable is labeled with its item #, key specifications, and batch number.
- Made from Thorlabs' Ø100 µm Core Multimode InF3 Fiber Manufactured In-House
- Antireflection Coated on Both Ends for 4.0 - 4.6 µm
- <0.50% Average Reflection Loss
- SMA905 Connectors with Metal Ferrules
- Stocked in 1 m Lengths
- Custom Lengths Available by Contacting Tech Support
- Stiff, Ø3.0 mm Plastic Jacket
- Two Protective Caps Included
| Item #a | Fiber | Transmission Rangeb,c |
Typical Attenuation |
Maximum Attenuationb |
Core Diameterb |
Cladding Diameterb |
NAb,d | Bend Radiusb (Short Term/ Long Term) |
Connectors | Jacket | Operating Temp. |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MF11L1AR1 | FFH10026e | 310 nm - 5.5 µm | 0.08 dB/m @ 2.5 µm and 3.6 µm |
≤0.25 dB/m (for 2.0 - 4.6 µm) |
100 ± 2.0 µm | 192 ± 2.5 µm | 0.26 ± 0.02 @ 2.0 µm |
≥25 mm / ≥50 mm | SMA905 | Blue PVDF (Ø3 mm) |
-40 to 85 °C |
Zoom
Click for Details
Each fluoride patch cable is labeled with its item #, key specifications, and batch number.
- Patch Cables Made from Thorlabs' Ø200 µm Core Multimode InF3Fiber Manufactured In-House
- SMA905 or FC/PC-Compatible Connectors with Metal Ferrules
- Stocked in 1 m and 2 m Lengths
- Custom Lengths Available by Contacting Tech Support
- Stiff, Ø3.0 mm Plastic Jacket
- Two Protective Caps Included
- SMA905-Terminated Cables: Stainless Steel Caps
- FC/PC-Compatible Cables: Plastic Caps
| Item # Prefixa |
Fiber | Transmission Rangeb |
Typical Attenuation |
Maximum Attenuation |
Core Diameter |
Cladding Diameter |
NAc | Bend Radius (Short Term/ Long Term) |
Connectors | Jacket | Operating Temperature |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MF21 | FFM20026 | 310 nm - 5.5 µm | 0.1 dB/m @ 2.5 µm and 3.6 µm |
≤0.25 dB/m (for 2.0 - 4.6 µm) |
200 ± 10 µm | 290 ± 10 µm | 0.26 ± 0.02 @ 2.0 µm |
≥40 mm / ≥80 mm |
SMA905 | Blue PVDF (Ø3 mm) |
-40 to 85 °C |
| MF22 | FC/PC-Compatibled |
Multimode Patch Cables