| Paper | Title | Page |
|---|---|---|
| TUPB35 | Velocity of Signal Delay Changes in Fibre Optic Cables | 248 |
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Most timing systems used for particle accelerators send their time or reference signals via optical single mode fibres embedded in cables. An important question for the design of such systems is how fast the delay changes in the fibre optic cable take place, subject to the variation of the ambient air temperature. If this information is known, an appropriate method for delay compensation can be chosen, to enable a phase stabilised transmission of the timing signals. This is of interest particularly with regard to RF synchronisation applications. To characterise the velocity of the delay change, the delay behaviour after a sudden temperature change will be described. When trying to determine the step response, two problems occur. On the one hand, the material parameter of the coating, necessary for the calculation, is typically unknown. On the other hand, the measurement of the step response under realistic conditions is very laborious. Thus in this presentation it will be shown how the step response and, accordingly, the velocity of the delay change in a fibre optic cable can be calculated by means of theoretical considerations, utilizing the typical geometry of fibre optic cables. |