Optical fibre switches have a broad range of applications such as optical fibre measurements/test, remote fibre monitoring, telecommunications, spectroscopy (including Raman and fluorescence), industrial production and process control and biomedical. They are used in data traffic routing, cross connects, sensing/monitoring systems, protection and bypass, in laboratories, manufacturing and R&D.
Optical fibre switches come in all shapes, sizes, colours and more. There are a range of technologies and techniques that need consideration when deciding what FO switch best meets application requirements. Fibre compatibility is vital to ensure minimal losses, this is just one of the many considerations for 1 X N, N X M configurations.
There are versions based on moving parts, repeatability and stability play a major part in their selection. Solid state non mechanical are well suited to specific higher switching speed applications. There are different technologies and techniques such as thermal activated, prism switched, optomechanical, magneto-optic, mechanical V grove alignment/stepper motor and more.
Most common switches are V groove alignment (direct fibre alignment), prism (micromechanical), beam steering techniques and MEMs, these are optomechanical. High speed switches have no moving parts and rely on organic materials in the light path, both electro-optic and magneto-optic technologies are used.
Important considerations when selecting switches in addition to switching time is interface/surface reflections (return loss) resulting from the light path components. Interfaces can be AR coated to reduce glass to air interfaces, other options are index matching, etc.