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Optical Switching
The rapid expansion
of optical communication has lead to the widespread adoption of wavelength
divisional multiplexing (WDM) as a method of expanding the capacity of existing fibre
networks. This technique involves launching a number of different wavelengths
down a single fibre creating the need for a number of components with the
ability to multiplex, demultiplex, switch, route, monitor and attenuate each
individual wavelength within the packet of wavelengths travelling down the fibre.
This places considerable pressure on the optical switching components needed to
process the channel.
To date all the
components have relied upon passive elements to handle the optical processing.
Active switching can be handled by converting light back in electrical signals
and processed much like a telephone exchange then re-launched. This technique is
expensive and performance limiting as the critical path is now determined by the
electronics rather than the optics.
The ideal solution is an optical switch (ASIL) that can differentiate wavelengths, switch multiple beams, has a low insertion loss, can switch at high speed and is rugged enough to be integrated into land or sea lines. There are number of specific areas that could benefit from such a device:
 | Add/Drop Multiplexing (ADM) This is the ability to add or drop certain wavelengths without having to separate all the wavelengths in the channel. Channel Monitoring | This involves monitoring of the power, signal-to-noise(SNR) and wavelength of the channel Protection switching | Is involved in rerouting channels in the event of a fibre cut. This is presently handled by providing two alternative paths per node, known as Synchronous Optical Networks (SONET) Cross connects | This is also known a free space switching where an array of input fibres can be cross-connected to an array of output fibres. |
DigiLens™ technology offers a combination of low scattering, high switching efficiency, large dynamic range, microsecond switching time, and a one step inexpensive manufacturing process enabling the expansion of the fibre capacity without the need to lay new fibre.
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