Caption

Fibre optic laser unit. Coloured scanning electron micrograph (SEM) of a laser unit used in fibre optic communications. A human hair (orange) is shown for scale. Fibre optics carry information as pulses of laser light, and are far more efficient than electrical wires. The tiny laser here sends the pulses along the glass fibre optic cables. The yellow circle (upper centre) is the apparatus which actually focuses the light into the glass fibre. These components are found in practically every digital phone switch. Magnification: x25 at 5x7cm size.