There are many methods for terminating fibre optic cables. Choosing the right method depends on application, engineers experience, cost and also personal preference. Here is an outline of the most popular methods.
Epoxy Polish
The original fibre termination process which involves gluing the
connector
onto the fibre and then polishing the connector end face to achieve a good finish. Either heat cure or anaerobic cold cure epoxy can be used and almost all available connector styles can be terminated with this method. Epoxy polish connectors can also be fitted to the widest variety of fibre from 250µm up to 3mm jacketed fibre and are able to withstand many diverse environmental conditions making epoxy polish a very robust and versatile termination method. However, although not difficult to terminate, some training is required and they are more suited to the high volume user with a stable work force as it is experienced engineers that consistently provide the best termination. Probably the cheapest method once an initial set of tools has been purchased as connectors tend to cost pence as opposed to pounds with the required consumables, epoxy, polishing papers (or lapping films ) etc. also being very in-expensive. You can acquire everything you need in kits like the OPT-HEATKIT
and OPT-COLDKIT.
Provide a very low-loss termination.
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Pre-Loaded Epoxy – 3M Hot Melt
3M Hot Melt is a widely used fibre termination method that uses a connector pre-loaded with adhesive providing a convenient and fast termination. Connectors still require polishing so some degree of training is required but this is a far simpler method for polishing connectors, requiring fewer consumables. If a mistake is made during termination then the epoxy can be re-heated in order for the fibre to be re-positioned reducing the amount of scrapped connectors. Connectors are slightly more expensive but consumable costs are reduced with fewer connector styles available and generally only suitable for 900µm and 2/3mm jacket fibres. Provide a low-loss termination.
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Crimp
With this termination method, connectors are crimped onto the fibre and then polished to achieve the desired finish. This style of termination is very quick and can be performed by in-experienced engineers. Designed to be used almost anywhere, no power is needed and with systems like the 3M Crimplok performance meets the requirements of TIA 568B standards. For further information please Click Here for further information.
Crimp – No Polish
This is by far the easiest and fastest method for terminating connectors onto fibres. The termination is performed by crimping the fibre into a connector which has a pre-polished stub of fibre in the ferrule eliminating the need for any polishing. Only a few simple tools are required and engineers can become proficient at terminating in a very short period of time. Kits are available from Tyco Electronics in the form of their Lightcrimp+ system and from 3M with their No Polish Connector (NPC). No consumables or power are required and the termination can be carried out almost any where including confined spaces. Well suited for companies performing a limited amount of fibre terminations with no dedicated fibre engineers. Only the most common connectors are available and they tend to be very expensive. However, when all installation costs are taken in to consideration, due to the speed with which they can be terminated, costs per installed connector may be cheaper.
Mechanical Splice
Normally used for quick fix repairs and temporary installations, mechanical splices are used for joining two fibres together. Very simple to use requiring few tools and almost no training, two cleaved fibres are mated together in a clamping device to complete the termination. Splices can usually be re-used but cost is very high. Some methods, like
3M
Fibrlok, use a jig to help in the termination, others like
Tyco Electronics Corelink system is more of a manual process.
Fusion Splice
Fusion splicers are used to join fibre cables together or connect
‘pigtails’,
normally a 1/1.5m length of buffered fibre factory terminated with a
connector
for minimum loss, to provide the least possible loss within a fibre optic infrastructure. Most modern fusion splicers, like those from
Furukawa,
are fully automatic, providing an excellent loss with minimal fibre preparation, therefore requiring very little training for the engineer. Probably the best method for terminating singlemode fibres due to the exceptionally low losses that are required. Most machines are portable and light weight and can be battery operated enabling them to be used in the field. The best fusion splicers use a core to core alignment system which physically aligns the core of the fibre ensuring minimal loss during the termination process. Cladding alignment is the next most common method, but as it aligns the 125µm cladding of the fibres, a higher loss should be expected. Fusion splicers are very expensive costing several thousand pounds so they are really only practical for those terminating fibre everyday, however, hiring them for individual jobs could prove very cost effective.
