摘要 |
<p>Optical fibre cable comprising a tube (2) in which is inserted at least one optical fibre (3), and a mixture (11) composed of a water-mediated expanding powder and a material with a particle size less than that of the said water-mediated expanding powder is inserted in the said tube (2). The percentage of the said powder in the mixture is in an amount such as to block the flow of water to within a distance of less than about three metres from the point of ingress of the said water in twenty-four hours and such as to bring about an increase in attenuation in the said optical fibre, after it has been housed in the said cavity, of less than 0.02 dB/km.</p> |