Multimode Graded-Index

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Multimode Graded-Index



Multimode Graded-Index

Our graded index fibre optic feedthroughs are constructed with 62.5/125µm core/clad graded-index multimode fibres, they are designed for vacuum applications requiring fibre optic connection from inside a vacuum system to external equipment. The fibre is hermetically sealed into a stainless steel shell using the latest in glass bonding technology and terminates on both vacuum and air side with standard SMA 905 terminations.
Ultra High Vacuum polyimide buffered optical fibres are available to meet the demands of UHV environments.
All of our optical fibre is constructed as a core-cladding composite. The core, or the filament that guides the light consists of a thin strand of high transmission fused silica. The cladding consists of an outer layer of doped, lower refractive index fused silica. This two layer design tightly confines the light to the central core of the fibre which in turn delivers a maximum amount of light at the far end. We also closely control the fibre diameter during the drawing process, allowing the fibre to centre well in connectors and boast a low loss rate.

Graded-Index multimode fibre is a great choice for bridging the gap between singlemode and step-index multimode fibres, giving up some bandwidth for ease of termination and light launch.
Lower cost than singlemode.
Primarily used for data communication.
Less useful for power delivery applications.
Recommended for Graded-Index applications requiring medium distance (2-15km) fibre lengths.

UHV compatible construction

62.5µm core / 125µm clad fibre
SMA 905 connector interface
High temperature rated 250°C
ConFlat® compatible flange mounts
KF compatible flange mounts
Polyimide / aluminium buffered vacuum rated optical cables

Materials St.St., Glass, Quartz
Vacuum Range
CF Flanged : atm to 1×10-10Torr
KF Flanged : atm to 1×10-8Torr
Temperature Range*
CF Flanged : -269 to 250°C
KF Flanged (Viton® seals) : -29 to 150°C
Vacuum Cables : -65 to 200°C
Air cables : Up to 80°C
Thermal Gradient : 25°C/min (max)
Optical Fibre
Operating wavelength : 800nm to 1300nm (optimised for both wavelengths)
Bare fibre : Pure fused silica core
Cladding : Fluorine doped silica
Buffer : Polyimide
Fibre profile : Graded-index multimode
Numerical aperture : 0.27±0.02 or 31.3°
Fibre Bend Radius:
Short term 400 x core diameter
Long term 8400 x core diameter
Attenuation @ 850nm : ≤3.0dB

Attenuation @ 850nm : ≤0.8dB
Power  :  <1W

* - Assembly rating is reduced to that of the lowest rated

Product CodeFig. No.No. F/TFibre Dia.FlangePriceQuantityPDF & STP
FOA-GI62.5-16CF 1 1 62.5µmDN16CF £541
FOA-GI62.5-40CF 1 1 62.5µm DN40CF £550
FOA-2GI62.5-40CF 1 262.5µm DN40CF £966
FOA-GI62.5-16KF 2 1 62.5µm DN16KF £529
FOA-GI62.5-40KF 2 1 62.5µm DN40KF £543
    FOA-2GI62.5-40KF 2 262.5µm DN40KF £961
    FOA-GI62.5-B 31 62.5µm Bolt £433
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