ECOC 1975 - ECOC 2013

194
CONNECTIONS FOR OPrICAL CABLES: DESIGN AND MEASUREMENTS
G Le Noane and R Bouillie
Various connedions problems are to be solved for optical fibre systems purposes.
On the complete system diagram, we can number three connexions types
:
a) - Connection between opto-electronical components and the fibre ends
or an "extremity" cable. It must be collapsible;
b) - Conne±ion between this extremity cable and the optical cable. It
must also be collapsible ;
c) - Connedion between optical cables themselves. They can be fixed or
collapsible.
a) and b) cases suppose to resolve a certain amount of problems such as losses,
reliability, etc •.• but as these conne±ions are a small number, these
problems are not very important, and mean performances can be sufficient. But
in the c) case, the connation number may be great, and the loss problem becomes
the most important.
If we assume cable lenghts to be about .5 km, we can obtain between 10 and
20 connectors between repeaters. System considerations limit to 10 dB total
conne±ion losses, so each cable to cable connexion must be less than 0.5 dB.
From this first assumption, we have made different connector types.
Extremity connectors
We present two of them, for light emitting diodes and photo detectors. Some
experiments have led us to the conclusion that dry connectors are the best
matched to As Ga component life time.
Their principle is displayed on the fig. 2. Losses of 17 dBm have been performed
repetitivily between L.E.D. and CORNING Silica fibres.
We have looked after the best matching lens to connect strip laser diodes to
large core Corning fibres. SELFOC lenses or plastic lenses are used, and the
loss can fall down to less than 1. dB.
Cable connections
A first study allows to realize the junction by fusing the fibre glass into
various small furnaces, Temperature, geometrical arrangement, fusing conditions
are tested.
A second one deals with a collapsible connector, using the automatic x - y
positioning obtained by an elastomer compression to ensure the 2 positioning
we prepare the end surface by using various saws or by polishing.
G. LE NOANE - R. BOUILLIE with the "Centre National d'Etudes des Telecommunications".