fibre optic benefits

metal coated fibre

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Metal Coated Fibre

These high performance fibres use pure metals of copper, aluminium and gold to give higher temperature use, better hermeticity and higher strength than polymer coated fibres. Polymer coated fibres can operate at temperatures of up to 300oc, whereas metal coated fibres can withstand temperatures of up to 700oc for short periods, or 500oc for longer periods.

This compares well with gold coated fibres, but at a fraction of the cost.

The benefits of this fibre include;

  • Operates under high temperatures- 300oc for shorter periods, 500oc for longer periods
  • Can be made in long lengths (several km)
  • Comes in a wide variety of fibre types, including single mode, graded index and step index large core fibres in UV and IR grades of silica.

Single Mode Fibres

Available for 800nm and 1300-1550nm use (other wavelenths are available to order).

This type is particularly useful for high performance sensors.

Specification
Single Mode 800-125
Single Mode 1300-125
Operating Wavelength (nm)
800-900
1250-1600
Mode field diameter (µm)
7
9
Cut off wavelength (nm)
770
1170
Attention dB/km
8-12
4-5
Coating Diameter (µm)
165
165
N.A
0.1
0.1

Graded Index Fibres

In some cases, the fibre itself is the sensing element, for example, in distributed sensors like temperature and strain. The fibre coating usually determines the minimum and maximum operating temperatures of the sensors, by using ours fibres this can range from absolute zero right up to 500-700oc (by operating the fibre in an inert atmosphere, 700oc can be tolerated indefinately).

Fibre lengths can be used up to about 1km. A metal coating applied to a small diameter (125µm) increases the attenutation of the fiber, the thicker the coating the higher the loss. By controlling this coating thickness we can make a 50-125µm grade index fiber with attenuation of 10-15dB/km (at 1300nm). By increasing the cladding diameter of the fibre to 200um we can make a graded index fiber with an attenutation approximately 10x's lower (<1.5dB/km). This 50-200µm fiber can be connected to the industry standard 50-125 fiber using connectors with a 200µm bore, or the fibre can be supplied with a 50-125 pigtail (fusion spliced).

Specification
Graded Index 150-125
Graded Index 150-200
Core Diameter (µm)
50
50
Cladding Diameter (µm)
125
200
Coating Diameter (µm)
165
260
Attenution dB/km
12-15
<1.5
N.A
0.15
0.15

Multimode Fiber- Step Index

These are recommended for spectroscopy due to their very low flourescence. They can also be used in all UHV applications. We can offer vacuum feedthroughs using these fibres that are epoxy free. Epoxy free patchcords are available for internal vaccum chamber use.

The multimode step index silica-silica fibres have a pure silica core and dropped silica cladding.

Specification
 
Core Material
High purity synthetic silica
Cladding Material
Doped Silica
Numerical Aperture
0.22+0.02
Minimum bend radius (short term)
40x's fibre radius
Minimum bend radius (long term)
100x's fibre radius
Typical spot values of attenuation
248nm (KrF laser) 1.2dB/m 308nm (XeCL laser) 0.26dB/m
Operating Temperature
-270oc to +700oc
Max intensity of transmitted power
CW up to 100KW/CM2 for pulsed lasers (<1µS) 500KW/CM2
The UV Grade

High OH & will transmit light from 180-1200nm.

UV Specification UV200 UV400 UV600 UV1000
Core Diameter (µm)
200
400
600
1000
Cladding Diameter (µm)
212
424
636
1060
Coating Diameter (µm)
270
530
750
1320
The IR Grade

Low OH & will transmit light from 500-2600nm.

IR Specification IR200 IR400 IR600 IR1000
Core Diameter (µm) 200 400 600 1000
Cladding Diameter (µm) 212 424 636 1060
Coating Diameter (µm) 280 530 750 1320

For further information or to place an order please contact us on 01302 338210 or email us here.