Investigation of the loss modes induced in optical fibres during the cabling process

  • P. Sutton

    Student thesis: Master's Thesis


    The process of fibre optic telecommunication cable production is hampered by a number of cable induced sources of attenuation which act upon the fibres. The majority of fibres receive a "normal" or average set of attenuation inducements. Despite this, observations of process attenuation increments show that some fibres show a greater increase in attenuation than others. The same levels of inducements therefore lead to varying levels of attenuation. These observations suggest that fibres have varying inherent levels of resistance to the loss modes of the cable and that the degree of resistance could be related to the fundamental parameters of the fibres. This work is aimed at evaluating this possible link, firstly between the fibre parameters and a specific mode of loss known as "microbending", and subsequently upon the fibre parameters and the general "cable induced loss mode".

    As part of this research programme, a highly repeatable test was developed capable of inducing very pure microbends in fibre and a strong correlation was established between the parameters of fibres and their performance on the test. The test method was investigated by British Telecom., and the cabling industry and adopted as a reference test method for the measurement of fibre susceptibility to the microbend effect.

    The work was extended to the cabled fibre product and using the same regression techniques as in the first part of the work, a possible link between cabled fibre performance, microbend test results and fibre parameters was explored. While it is shown that there is some correlation, it became evident at this stage of the investigation, that other variables apart from fibre parameters were affecting cable performance.

    The overall project resulted in an increased level of awareness and understanding of cable induced loss modes in general and microbending in particular.
    Date of Award1991
    Original languageEnglish
    Awarding Institution
    • Polytechnic of Wales

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