Variation of pulse delay with stress and temperature in jacketed and unjacketed optical fibres

The stability of optical-fibre delay lines is assessed by means of measurements of pulse transit times in unjacketed silica-based fibres. Data obtained for the effect of longitudinal stress and temperature are used to interpret the time delays found in jacketed fibres. It is shown that the application of close-fitting plastic cabling materials results in a residual fibre stress which is both temperature and humidity dependent.