Anglia Instruments Ltd

Fibre Optics

Fibre Optics

The use of fibre optics as light guidance allows a great modularity and flexibility in the setup of an optical measurement system.

Optical fibres can be made of many materials, such as plastic, glasses and silicates (SiO2). For high quality fibre optics, as used in spectroscopic applications, synthetic fused silica (amorphous silicon dioxide) is used, that can be intentionally doped with trace elements to adjust the optical properties of the glass.

The basic principle of light transport through an optical fibre is total internal reflection. This means that the light within the numerical aperture of a fibre (NA = input acceptance cone) will be reflected and transported through the fibre. The size of the numerical aperture depends on the materials used for core and cladding.

Two basic types of silica fibres can be distinguished - singlemode and multi-mode, depending on the propagation state of the light, travelling down the fibre.

For most spectroscopic applications multi-mode fibres are used. Multi-mode fibres can be divided into 2 subcategories, step-index and graded-index. A relatively large core and high NA allow light to be easily coupled into the fibre, which allows the use of relatively inexpensive termination techniques. Step-index fibres are mainly used in spectroscopic applications.

Graded-index multimode fibres have a refractive index gradually decreasing from the core out through the cladding. Since
the light travels faster in material with lower refractive index, the modal dispersion (amount of pulse-spreading) will be less. These graded-index fibres are mainly used in telecommunication applications, where bandwidth at long distance (2-15 km) plays an important role.

In the 'Fibre Optic Properties' and 'Probe Properties' sections below, some basic fibre optic components and properties are presented.

Fibre Optic Properties
Fibre Optic Properties
The use of fibre optics as lig...
Probe Properties
Probe Properties
All our fibre optic cables and...
Fibre Optic Cables
Fibre Optic Cables
Fiber optic cables can be made...
Reflection Probes
Reflection Probes
The FCR-7xx200-2 is a standard...
Reflection Probes with Reference
Reflection Probes with Referen...
The FCR-14xx200-2-REF is a spe...
Reflection Probes with Small Tips
Reflection Probes with Small T...
The FCR-7xx200-2-1.
Reflection Probes for Powders & Thick Fluids
Reflection Probes for Powders ...
The FCR-7xx200-2-45 is a refle...
Industrial Reflection Probe for Powders & Thick Fluids
Industrial Reflection Probe fo...
The FCR-7xx200-2-45-IND is a h...
Mini Transmission Immersion Probe
Mini Transmission Immersion Pr...
The Mini Transmission Dip Prob...
Industrial Fluorescence Probe
Industrial Fluorescence Probe
For fluorescence applications,...
Micro Transmission Immersion Probe
Micro Transmission Immersion P...
The Micro Transmission Dip Pro...
Transmission Immersion Probe
Transmission Immersion Probe
The transmission dip probe is ...
Transmission Immersion Probe with Variable Pathlength
Transmission Immersion Probe w...
The transmission dip probe wit...
Transmission Immersion Probe with Disposable Tip
Transmission Immersion Probe w...
For absorption measurements in...
Solarisation Resistant Fibres for DUV Applications
Solarisation Resistant Fibres
Most spectroscopic application...
Fibre Optic Sleeves
Fibre Optic Sleeves
For different applications, we...
Fibre Optic Connectors
Fibre Optic Connectors
SMA connectors We supply al...