Products HomeUltra-High-Vacuum Fiber Feedthrough Flanges
- Fiber Feedthrough CF and KF40 Flanges for Ultra-High Vacuum
- SMA Terminated on Both Sides
- Available for 200 - 1200 nm, 400 - 2400 nm, or 0.3 - 5.5 µm
VC2H2S
CF Flange for
Ø200 µm SMA Fibers
Front
Back
VK4L4S
KF40 Flange for
Ø400 µm SMA Fibers
ADASMAV
Vacuum-Compatible Mating Sleeve
Application Idea
The MV11L05 Vacuum-Compatible Multimode Patch Cable connected to the VK4H1S Fiber Feedthrough KF40 Flange using the ADASMAV Vacuum-Compatible Mating Sleeve. The feedthrough can be can be mated to a vacuum system using a wing nut clamp and an O-ring carrier (not shown).
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| Fiber Feedthrough Common Specifications | ||
|---|---|---|
| Insertion Loss | ≤2.3 dB | |
| Max Optical Power | 1 W | |
| Leak Rate | ≤1 x 10-10 mbar⋅L/s (Helium Standard) | |
Features
- Quickly Connect SMA-Terminated Fibers to a Vacuum Chamber
- CF (Ø2.75") or KF40 (Ø2.17") Flange Options
- Hermetically Sealed Multimode Step-Index Fiber
- Ø100 µm, Ø200 µm, Ø400 µm, or Ø600 µm Core
- High OH (200 - 1200 nm), Low OH (400 - 2400 nm), or InF3 (310 nm - 5.5 µm)
- Compatible with Thorlabs' Vacuum-Compatible Multimode Fiber Optic Patch Cable
- Bake-Out can be Conducted at High Temperatures
- Up to 250 °C for High- and Low-OH Fiber
- Up to 90 °C for InF3 Fiber
- Vacuum-Compatible Mating Sleeve and Flange Mounting Components Sold Below
Thorlabs manufactures Ultra-High-Vacuum Compatible Fiber Feedthroughs for both CF Ø2.75" (DN40) and KF40 flanged systems. These feedthroughs allow for optical coupling into ultra-high-vacuum (UHV) systems using SMA905-terminated fiber patch cables and mating sleeves. Each fiber feedthrough incorporates a hermetically sealed step-index multimode optical fiber in a stainless steel shell, provides a low insertion loss of ≤2.3 dB, and can handle optical powers up to 1 W. The flanges are double vacuum bagged to help prevent contamination when transported into a cleanroom environment.
The fiber feedthroughs feature male SMA905 connectors on both sides; mating sleeves may be used to connect fiber patch cables. For the side of the feedthrough that is inside of the vacuum environment, the ADASMAV vacuum-compatible SMA-to-SMA mating sleeve, available below, can be used to connect a vacuum-compatible patch cable. Constructed using 304 stainless steel, this adapter is designed to be used within ultra-high vacuum systems. Feedthroughs with high- or low-OH fiber feature a Ø0.063" (Ø1.6 mm) hole through the body to serve as a vent, allowing trapped gas to escape. When using fiber patch cables in a vacuum environment, ensure that the cables are vacuum compatible. The mid-IR KF40 flange fiber feedthrough (Item # VK4F1S) has a 17.78" (451.6 mm) long, ruggedized, hermetic, permanently attached, InF3 multimode fiber cable ending in an male SMA905 connector on the side facing away from vacuum.
The high- and low-OH fiber feedthroughs have unique laser-welded joints that provide sturdier construction than traditional adhesives and greatly minimize leak rate. In addition, the locations of these laser welds and the hermetic glass-to-metal seal ensure that only external, easy-to-clean surfaces are directly exposed to the vacuum. Since there is no epoxy on the vacuum side of the feedthrough, there is minimal contamination and gas load on the vacuum system.
Thorlabs also sells additional high-vacuum CF components, KF16-, KF25-, and KF40-flanged components and accessories, as well as an extended line of vacuum-compatible parts.
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This attenuation data was calculated as a function of wavelength for the fibers used in the UHV high-OH fiber feedthrough CF and KF40 flanges.
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This attenuation data was calculated as a function of wavelength for the fiber used in the MIR fiber feedthrough KF40 flange.
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Click for Data
This attenuation data was calculated as a function of wavelength for the fibers used in the UHV low-OH fiber feedthrough CF and KF40 flanges.
| Posted Comments: | |
Sebastian Schäfer
(posted 2025-05-22 08:42:18.02) Can you also offer KF40 flanges with FC/PC connectors on both sides? EGies
(posted 2025-05-22 06:24:36.0) Thank you for contacting Thorlabs. I have reached out to you directly regarding this custom request. Slawomir Prucnal
(posted 2024-03-06 07:42:54.937) Good Afternoon,
we are constructing the vacuum chamber for optical measurements. I am very limited with the space and we need vacuum port for optical fiber. We bought already PAF2S-A4A and now we have to take fiber out of the vacuum. One option could be VC2H6S - Fiber Feedthrough for Ø2.75" CF Flange, High OH, Ø600 µm Core, 200 - 1200 nm, 0.22 NA, SMA but the CF 40 flange is a bit to big for us. Is it possible to have a smaller flange CF/KF25 or KF16?
Best regards,
Slawomir cdolbashian
(posted 2024-03-18 12:23:38.0) Thank you for reaching out to us with this inquiry! You are correct that we do not have anything that would exactly meet your needs at this time. I have contacted you directly with some options regarding your application and the need for custom sized flange. Mike Cook
(posted 2023-05-16 05:38:58.32) The pdf drawing of this part shows a weep hole on the atmosphere side. Is this a mistake on the drawing? jdelia
(posted 2023-05-17 10:56:38.0) Thank you for contacting Thorlabs. We can confirm that the weep hole is on the correct side, and this is not a mistake on the drawing. I have also reached out to you directly to discuss this further. |
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Figure G1.1 Ultra-High Vacuum Fiber Feedthrough CF Flange Cross-Section
- Construction Enables use at Vacuum Pressures Down to
1 x 10-10 Torr - Mates to Ø2.75" (DN40) CF Flanges
- Hermetically-Sealed Fiber Tip Limits Virtual Leaks
- 304 Stainless Steel Construction for High Durability and Low Outgassing
- Laser Welded Body; Adhesive-Free on Vacuum Side
- CF Flange Mounting Hardware Pack and Copper Gaskets Sold Below
Our Ultra-High-Vacuum-Compatible Ø2.75" (DN40) Fiber Feedthrough CF Flanges allow for optical coupling into ultra-high-vacuum (UHV) systems using SMA905-terminated fiber patch cables and mating sleeves. Constructed using 304 stainless steel, every feedthrough is designed to be used within UHV systems down to 10-10 Torr.
The CF-style flange utilizes a knife-edge mechanism to create an airtight seal when used properly with a copper gasket (sold below). Six 1/4" (M6) through holes allow the these fiber feedthroughs to be bolted onto any standard DN40 CF flange. As the bolts of the mating pair are tightened, the knife edge bites into the copper gasket, deforming it. The compressed copper fills all the machining marks and surface defects, which yields a leak-tight seal. Please note that the copper gasket and bolts must be purchased separately.
Note: Mounting hardware and CF flange copper gasket seals are not included.
| Item # | Fiber Core | Fiber | Wavelength Range | NA | Maximum Temperature |
|---|---|---|---|---|---|
| VC2H1S | Ø100 µm | High OH | 200 - 1200 nm | 0.22 ± 0.02 | 250 °C |
| VC2L1S | Low OH | 400 - 2400 nm | |||
| VC2H2S | Ø200 µm | High OH | 200 - 1200 nm | ||
| VC2L2S | Low OH | 400 - 2400 nm | |||
| VC2H4S | Ø400 µm | High OH | 200 - 1200 nm | ||
| VC2L4S | Low OH | 400 - 2400 nm | |||
| VC2H6S | Ø600 µm | High OH | 200 - 1200 nm | ||
| VC2L6S | Low OH | 400 - 2400 nm |
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Click to Enlarge
Figure G2.1 This cross-section illustrates the interior of our UHV high- and low-OH fiber feedthrough KF40 flanges.
- Construction Enables use at Vacuum Pressures Down to 1 x 10-8 Torr
- Mates to KF40 (Ø2.17") Flanges
- Hermetically-Sealed Fiber Tip Limits Virtual Leaks
- 304 Stainless Steel Construction for High Durability and Low Outgassing
- Laser Welded Body on High- and Low-OH Fiber Feedthroughs
- High-OH and Low-OH Fiber Feedthroughs Adhesive-Free on Vacuum Side
- KF40 Flange-Centering O-Ring Carrier and Wing Nut Clamp Sold Below
Our Ultra-High-Vacuum-Compatible Fiber Feedthrough KF40 Flanges allow for optical coupling into ultra-high-vacuum (UHV) systems using SMA905-terminated fiber patch cables and mating sleeves. Constructed using 304 stainless steel, every feedthrough is designed to be used within UHV systems down to 10-8 Torr. Referred to as NW, QF, or DN flanges, KF flanges are ideal for quickly assembling vacuum systems due to their ease of use, maintenance, and reusability. The MIR fiber feedthrough (Item # VK4F1S) has a 17.78" (451.6 mm) long, ruggedized, hermetic, permanently attached, InF3 multimode fiber cable ending in a male SMA905 connector on the side facing away from vacuum.
These KF flanges are ISO-standardized vacuum fittings that can be mated to a vacuum system using a wing nut clamp and an O-ring carrier (sold below). The angled sides of the wing nut clamp compress the O-ring between the flanges, quickly creating a vacuum seal. The wing nut clamp, which has M5 x 0.8 threads, requires only hand tightening, allowing parts to be quickly swapped in and out of a KF-flanged system. Please note that the O-ring carrier and wing nut clamp must be purchased separately.
| Item # | Fiber Core | Fiber | Wavelength Range | NA | Maximum Temperature |
|---|---|---|---|---|---|
| VK4H1S | Ø100 µm | High OH | 200 - 1200 nm | 0.22 ± 0.02 | 250 °C |
| VK4F1S | InF3 | 310 - 5500 nm | 0.26 ± 0.02 | 90 °C (Bake Out); 75 °C (Operating) | |
| VK4L1S | Low OH | 400 - 2400 nm | 0.22 ± 0.02 | 250 °C | |
| VK4H2S | Ø200 µm | High OH | 200 - 1200 nm | ||
| VK4L2S | Low OH | 400 - 2400 nm | |||
| VK4H4S | Ø400 µm | High OH | 200 - 1200 nm | ||
| VK4L4S | Low OH | 400 - 2400 nm | |||
| VK4H6S | Ø600 µm | High OH | 200 - 1200 nm | ||
| VK4L6S | Low OH | 400 - 2400 nm |
Zoom| Vacuum Compatibility Specifications | |
|---|---|
| Vacuum Compatibility as Packageda | 10-10 Torr |
| Materials | 304 Stainless Steel |
| Preparation and Packaging | Chemically Cleaned and Double Vacuum Bagged |
- Air-Spaced SMA to SMA Mating Sleeve for Ultra-High-Vacuum Applications
- Constructed from 304 Stainless Steel
- <1.5 dB Insertion Loss (Typical Loss for a Pair of Ø200 µm Core Multimode Fibers)
- Double-Bagged for Cleanroom Environments
- Compatible with Thorlabs' Vacuum-Compatible Multimode Fiber Optic Patch Cables
Thorlabs' ADASMAV Mating Sleeve is a vacuum-compatible version of the ADASMA SMA to SMA Mating Sleeve. Constructed using 304 stainless steel, this adapter is designed to be used within ultra-high vacuum systems (>10-10 Torr) and features a Ø0.063" (Ø1.6 mm) vent hole in the side to allow trapped gases to escape (see Figure 490A). Unlike the standard version, the ADASMAV is only compatible with SMA905-style connectors. A 304 stainless steel washer and nut are included for custom mounting.
Many of our patch cables can be special ordered for vacuum use. Contact Tech Support for details.
Vacuum Compatibility Information
Our vacuum-compatible adapter is chemically cleaned and prepared for vacuum applications before packaging. It is compatible directly out of the packaging with vacuum environments down to 10-10 Torr. With additional cleaning and processing, it can be used at even lower pressures, only limited by the outgassing rate of the stainless steel. The material properties of the stainless steel and the cleaning methods completed by the end user should be used to determine the appropriateness of these products and materials in a specific vacuum system. Please note that using caps or panels not rated for vacuum applications with the ADASMAV is not recommended.
We also offer other vacuum-compatible components which may be used in vacuum applications.
Zoom| Item # | Included O-Ring Dimensions | ||
|---|---|---|---|
| OD | ID | Thickness | |
| KF40CR-F | 2.05" | 1.65" | 0.20" |
- KF40CR-F Centering O-Ring Carrier for KF40 Flanges
- Holds O-Ring in Place Between KF Flanges
- Creates Vacuum Seal When Compressed Against KF Mating Surfaces
- Includes Fluorocarbon O-Ring
- KF40WNC Wing Nut Clamp for KF40 Flanges
- Secures Two KF40 Flanges Separated by an O-Ring
- Fast Hand Tightening; No Tools Required
Thorlabs offers a centering O-ring and a wing nut fastening clamp for mating KF40 flanges to a vacuum system. The angled sides of the wing nut clamp compress the O-ring between the flanges, quickly creating a vacuum seal. The wing nut clamp, which has M5 x 0.8 threads, requires only hand tightening, allowing parts to be quickly swapped in and out of a KF-flanged system.
For best performance, a very thin coating of vacuum grease should be applied to the O-ring before installation. This should be done by hand while wearing gloves, leaving just enough grease to cause the O-ring to shine. The O-ring and its mating surfaces should be visually inspected before installation to ensure there is no debris which may impede proper contact and cause a leak. O-rings should be regularly inspected to spot dry rot, cracking, tearing, or accumulation of debris from normal operation. Replace any O-ring that is suspected of causing a leak. Additionally, be aware that under vacuum pressure, the KF connection may undergo additional compression, causing the wing nut clamp to loosen. Some additional tightening may be performed, but be careful not to overtighten the clamp, as the wing nut may become difficult to remove or jammed when the system returns to atmospheric pressure. Do not remove a wing nut clamp while a system is under vacuum.
We also offer KF16 wing nut clamps and O-rings, as well as KF25 wing nut clamps and O-rings.
Ultra-High-Vacuum Fiber Feedthrough Flanges