Telecommunications
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| Typical telecommunications components |
Ceramic materials are used in a wide range of applications in this industry. The main use of zirconia is for ceramic ferrules and ceramic sleeves for connecting fibre optic cables.
The excellent surface finishes and strengths which are attainable with TZP’s has led to their use in optical fibre technologies where they are used as split coupling devices for optical fibres.
In parallel with the injection moulding technology which has been developed to produce such components, diamond finishing techniques have also been improved to allow tolerances of 1 micron to be achieved on a repeatable basis.
Why Zirconia?
Zirconia ceramic ferrules offer distinct advantages:
- chip and crack free
- smaller grain sizes achieve smoother finishes
- thermal expansion coefficient closer to that of the fibre
- a high modulus of elasticity and high impact resistance.
For more information on Ceramic Ferrules call us on 01270 501 000 or email us at info_crewe@coorstek.com
Ceramic Ferrules
Single mode connectors have ferrules which align the fibre cladding to the centre axis of the ferrule to within 1 – 2 micron. To achieve this, the connector hole diameter is carefully matched to the actual fibre diameter ( e.g. hole size 124, 125, 126 microns ). Alternatively, a larger hole with some form of active alignment procedure is used.
Single mode connectors tend to be expensive to manufacture and time consuming to assemble.
Multi mode connectors have ferrules with a 128 micron hole for nominally 125 micron fibre, so they are relatively easy to make and assemble.
Some multi-mode ferrules are made of plastic or stainless steel which can provide adequate tolerances for multi-mode application. However, neither of these are suitable for test leads due to increased wear and generally worse tolerances.
The manner in which the ferrule is polished is critical to return loss performance of single mode connectors.
A “flat polish” connector will cause around -14.7 dB return loss unmated, and up to -11.7 dB mated. ( e.g. two reflections ). A “PC” or “physical contact” connector will cause around -14.7 dB return loss unmated, and between -30 and -60 dB mated.
The mated performance is highly variable between polishing procedures (and operator experience), and also very sensitive to dirt and wear. Therefore, the so-called “super PC” or “ultra PC” polish connectors need constant measurement to verify their achieved performance. Also, their poor unmated performance limits their effectiveness in many applications.
Improvements can be achieved by using “APC” or “angled physical contact” polish connectors, which offer better than 60 dB return loss in all circumstances ( unless the fibre tip is dirty ).
For more information on Ceramic Ferrules call us on 01270 501 000 or email us at info_crewe@coorstek.com
Alignment Sleeve
The alignment sleeve is located in the through connector and is used to align the ends of 2 ferrules so that the cores of the 2 fibres are aligned.
Alignment sleeves for single-mode fibre are generally made from beryllium copper or ceramic.
Whereas under ideal conditions ceramic sleeves provide lower loss performance, the beryllium copper sleeves tend to be more forgiving of tolerance variations when mating connectors between different manufacturers. Metal alignment sleeves can bend and then cause poor performance.
For more information on ceramic sleeves call us on 01270 501 000 or email us at info_crewe@coorstek.com
