Mid-IR SM Patch Cables


Mid-Infrared Optical Fiber and Fiber Patch Cables

  • Single Mode, Multimode, Doped, and High-Power Options
  • Transmissive from the UV up to 5.5 µm
  • Stable in Typical Lab Envionments and Easy to Handle
  • Return Loss Less Than 4% per Face


  • Offered Connectorized or as Bare Fiber
  • Available Configurations:
    • Single Mode
    • Multimode
    • Doped
    • High Power Screened
  • Indium Fluoride (InF3) and Zirconium Fluoride (ZrF4) Fibers
  • Transparent in the UV, Visible, Near Infrared, and Mid-IR Spectral Ranges
  • Core Sizes Optimized for Single Mode or Multimode Applications
  • Numerical Apertures Ranging from 0.10 to 0.35
  • Low Return Losses: <4% per Face

With the acquisition of IRphotonics' iGuide™ products, Thorlabs is pleased to extend its family of fiber products into the mid-infrared spectral region. These fibers, based upon zirconium fluoride (ZrF4) and indium fluoride (InF3) host glasses, feature excellent mechanical flexibility, good environmental stability, and high transmission over the 300 nm - 4.5 µm spectral range or 300 nm - 5.5 µm spectral range, respectively. Like the rest of our fiber selection, fluoride fibers can be provided in a range of core diameters, cutoff wavelengths, and numerical apertures, suiting a variety of applications.

These fibers offer a flat attenuation curve in the MIR wavelength range (see graph at right), aided by an extremely low hydroxyl ion (OH) content. They are fabricated using a patented technique that provides world-class purity, dimensional control, and strength. This technique gives us excellent control over the fibers' optical and mechanical properties, allowing lengths of hundreds of meters to be drawn. The fluoride fiber is stable under typical environmental conditions and humidity.

We are currently moving the fluoride fiber processes and equipment from IRphotonics to our facility in Newton, New Jersey. During this transition, a limited amount of bare fiber is available, and patch cables can be manufactured upon request. Thorlabs will be adding standard patch cables, hermetically sealed patch cables, and other items to its stock of MIR products in the coming months. We will also be able to provide custom fluoride fibers, both doped and undoped.



  • Chemical Sensing
  • Spectroscopy
  • Mass Spectrometry
  • Remote Sensing
  • Dermatology
  • General Surgery
  • Industrial & Scientific Diagnostics
  • Fiber Lasers
  • Amplifiers
  • Mid-IR Laser Delivery
  • Supercontinuum Sources
  • Aerospace
  • Defense
  • Infrared Countermeasure (IRCM) Systems


Single Mode MIR Fiber and Fiber Patch Cables
Fiber TypeSM Operating WavelengthaCore DiameterbAttenuationcNAbLong-Term Bend RadiusShort-Term Bend RadiusTensile StrengthOperating Temperature
ZrF4 2.0 to 4.5 µm 6 to 9 µm <0.2 dB/m
(from 1.3 to 3.8 µm)
0.10 to 0.35 ≥50 mm ≥10 mm ≥50 kpsi -62 to 90 °C
InF3 2.0 to 5.5 µm 10 to 17 µm <0.45 dB/m
(from 1.5 to 4.9 µm)
0.20 to 0.30 ≥40 mm ≥10 mm ≥50 kpsi -62 to 90 °C
  • Several SM operating wavelength ranges and cutoff wavelengths are offered. The best choice depends upon your range of interest. 
  • The core diameter and NA depend upon the SM operating wavelength range and cutoff wavelength. Other core diameters and NAs may be available through custom runs.


Multimode MIR Fiber and Fiber Patch Cables
Fiber TypeOperating WavelengthCore DiameterAttenuationaNALong-Term Bend RadiusTensile StrengthOperating Temperature
ZrF4 0.3 - 4.5 µm Six Choices from 85 to 600 µm;
See Table Below
<0.2 dB/m
(from 1.3 to 3.8 µm)
0.20 ± 0.02 ≥50 mm ≥50 kpsi -62 to 90 °C
InF3 0.3 - 5.5 µm 100 µm <0.45 dB/m
(from 1.5 to 4.9 µm)
0.20 to 0.30 ≥40 mm ≥50 kpsi -62 to 90 °C



Doped MIR Fiber and Fiber Patch Cables
Fiber TypeAvailable Dopants and CodopantsOperating WavelengthCore DiameterCore / Cladding OffsetCoating / Cladding OffsetNALong-Term Bend RadiusShort-Term Bend RadiusTensile StrengthOperating Temperature
ZrF4 or
Dy, Er, Ho, Nd, Pr, Sm, Tm, or Yb 0.3 - 4.5 µm ≤20 µm ≤1 µm ≤5 µm 0.20 ± 0.02 ≥50 mm ≥10 mm ≥50 kpsi -62 to 90 °C



High-Power-Screened MIR Fiber and Fiber Patch Cables
Fiber TypeOperating WavelengthAttenuation (Typ.)Core DiameterShort-Term Bend RadiusNAOperating Temperature
ZrF4 0.3 - 4.5 µm From 2.5 to 3.2 µm: ≤0.1 dB/m
At 633 nm: ≤0.3 dB/m
100 ± 5 µm 2.5 cm 0.20 ± 0.02 -62 to 90 °C
450 ± 15 µm 10 cm
600 ± 15 µm 30 cm

Our high-power-screened MIR fiber features a dual cladding for higher power handling. The primary cladding is glass, and a secondary, low-index polymer cladding is within the acrylate coating. The peak power density of the fiber depends upon launch conditions and laser specifications, including wavelength, pulse energy, pulse duration, repetition rate, and beam diameter.


Our Mission is to accelerate the advancement of optical technology for precision measurements and their applications from the table tops of research laboratories to standard use in communication and high technology industries. Our aim is to serve our customers. Our hope is to create a place for highly skilled people in an open environment

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