Abstract

There is increasing evidence that absorption loss between 1 and 1.6 μm is not negligible in OH free single mode fibres [1]. However, the absorption loss contribution to total attenuation in optical fibres has become difficult to assess with the achievement of lower losses. There are a nunber of reports [2-5] on methods of measurement, with one achieving a loss of less than one dB/km using a calorimetric method. We present a novel calorimetric technique, using a pyroelectric sensor material, polyvinylidene fluoride (PVF₂), which has the advantage of having a large pyroelectric coefficient and can be shaped to ideally suit this application. Using this material it is possible to measure sub-dB/km absorption losses with increased sensitivity with a few hundred milliwatts of laser power.