SWITCHING light pulses between different lines is a problem that has plagued telecommunications companies since they began using optical fibres. Currently, the only switches that can shuffle the connections are expensive and relatively unreliable.
But researchers at the University of Southampton think they may have cracked the problem by developing a simple and cheap way to change the light's course by reflecting it off sound waves.
Tim Birks and Philip Russell heat and stretch two optical fibres until their light-conducting cores fuse and form a narrow circular waist. Before and after the junction, the fibres remain independent.
Light travels down an optical fibre by bouncing from one side of the core to the other. The two fibres in the new device are "tuned" to carry signals travelling with slightly different angles of bounce, so light travelling up one fibre will not usually cross to the other. But by altering the ...
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