Before purchasing a fusion splicer/welder, the customer should necessarily determine the tasks to be performed. This refers, among others, to the average number of splicing operations on a monthly or annual basis, the number of splices done during one installation, and finally the kind of the networks (building, metropolitan, internal LANs, CCTV systems etc.).
Depending on the answers to the above questions, the customer can choose a more or less advanced model of a fusion splicer. One of the most important processes carried out by the splicer is the positioning of the fibres before the welding process. According to this criterion, splicers can be divided into three groups:
Splicers based on cladding alignment - this is the most economical option; the splicer adjusts the mutual positions of their cladding (the standard diameter is 125 μm) to minimize the difference. Theoretically, such a method of positioning results in a weld having a slightly larger attenuation compared to other solutions, especially in the case of fibres of poor quality, where the core is not placed centrally with respect to the cladding. In practice, however, the fibres sold today are of high quality and in most cases the parameters of the splices performed with this method do not differ from results achieved with the use of other methods.
Splicers with aligning geometric core positions - this method is used by the majority of splicers and many manufacturers and retailers wrongly describe them as devices with aligning (actual) core positions; the core geometry is obtained by optical means (visible light). The intensity of light in the fibre decreases as a function of depth, and with a given sensitivity and simple image analysis, it is possible to determine the approximate positions of fibre cores. This method has been optimized for good quality fibres, where the geometric position of the core is equivalent to its real position. When the core is embedded eccentrically, the parameters of the splice can be worse than in the case of fibre cladding alignment.
Splicers with alignment of (real) core positions - it is the most professional and at the same time the most expensive solution. The devices using this method can automatically recognize the type of welded fibres and arrange them according to their real cores. Such welds are characterized by the best performance parameters. The welding machines utilizing this method are several times more expensive than devices based on the previous solutions.