Create an Account  |   Log In

View All »Matching Part Numbers

Your Shopping Cart is Empty

Fiber End Caps

  • End Caps with Diameter up to 8 mm
  • Available Uncoated or with 1064 nm VAR Coating
  • Larger Diameter Caps Have Taper or Stem for Splicing
  • Ideal for High-Power Coupling or to Protect Photonic Crystal Fiber


Ø1 mm End Cap


Ø1.5 mm End Cap


Ø5 mm End Cap with Taper,
1064 nm VAR Coating


Ø8 mm End Cap with Taper and Stem,
1064 nm VAR Coating

Application Idea

FEC8S-1064 End Cap Spliced onto a Ø400 µm Core Fiber
(Not Shown to Scale)

Related Items

Please Wait

Click to Enlarge
Image of an FEC5-1064 Ø5 mm end cap with tapered lead-in prepared for splicing in the GLZ4001EC CO2 End Cap Splicer.


  • Ø1 mm, Ø1.5 mm, Ø5 mm, and Ø8 mm UV Fused Silica Coreless End Caps
  • Tapered Lead-in Simplifies Splicing Fiber onto Large Diameter Caps
  • Versions with 1064 nm VAR-Coated Face to Reduce Back Reflections
  • >80% Clear Aperture with ≤5 arcsec Parallelism Between End Faces
  • Protect Fiber End Face by Reducing Energy Density at Air-to-Glass Interface
  • Ideal for High-Power Fiber Lasers and Amplifiers, Biomedical Imaging, and Protecting Photonic Crystal Fiber
  • Splice onto Optical Fiber Using Our Vytran® CO2 End Cap Splicer

Thorlabs' UV fused silica end caps range in size from Ø1 mm to Ø8 mm. End caps with a 5 mm or 8 mm cap diameter have either a stem or tapered lead-in on one end to simplify splicing them onto a fiber; they also include a 1064 nm antireflection coating on the side opposite the taper to reduce back reflections. Complete specifications along with profiles and dimensions are in the table below.

Each end cap is coreless (no waveguide) to allow the incoming light to expand evenly in the homogeneous material. When spliced onto a fiber, the end cap reduces the intensity at the air-to-glass interface of the fiber face to prevent potential damage from high-power sources, such as Q-switched lasers or fiber amplifiers. End caps can also be used to seal off the air holes in photonic crystal fiber to prevent water from entering.

Application Note
These caps can be spliced onto optical fiber using our Vytran® CO2 End Cap Splicer. The GLZ4001EC Splicer is an advanced splicer that is designed for splicing numerous types of fiber directly onto a large-diameter end cap. Utilizing a tapered lead-in allows end caps up to Ø9.5 mm to be spliced, as shown in the image to the right. Without a lead-in the maximum end cap diameter is 5 mm.

Click to Enlarge

Coupling Light into and Out of Standard Fiber vs. End-Capped Fiber
Item # Profile
(Click for Details)
Clear Aperture
(Both Ends)
Surface Flatness
(Both Ends)
Parallelism Substrate Dimensions (See Profile)
DCap LCap LStem θTaper
FEC1 N/A >80% ≤λ/4
(633 nm)
≤5 arcsec UV Fused Silica 1.0 mm 2.5 mm N/A
FEC15 1.5 mm 3.8 mm
FEC5-1064 1064 nm
V Coat
(R < 0.25%,
0° ± 5° AOI)
>80% ≤λ/4
(633 nm)
≤5 arcsec 5.0 mm 12.5 mm N/A 60°
FEC8S-1064 8.0 mm 20.0 mm 4.0 mm
  • The antireflection coating is deposited on the side opposite the taper.

Posted Comments:
No Comments Posted

Fiber End Caps

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
FEC1 Support Documentation
FEC1Fiber End Cap, Ø1.0 mm, Uncoated
FEC15 Support Documentation
FEC15Fiber End Cap, Ø1.5 mm, Uncoated
FEC5-1064 Support Documentation
FEC5-1064Fiber End Cap, Ø5.0 mm, Tapered End, 1064 nm VAR Coating
FEC8S-1064 Support Documentation
FEC8S-1064Fiber End Cap, Ø8.0 mm, Tapered End with Stem, 1064 nm VAR Coating
Log In  |   My Account  |   Contact Us  |   Careers  |   Privacy Policy  |   Home  |   FAQ  |   Site Index
Regional Websites:East Coast US | West Coast US | Asia | China | Japan
Copyright © 1999-2021 Thorlabs, Inc.
Sales: 1-973-300-3000
Technical Support: 1-973-300-3000

High Quality Thorlabs Logo 1000px:Save this Image