CONNECTION MEANS FOR OPTICAL FIBRES

Abstract: The present invention relates to an optical connection means arranged in order to rearrange and connect optical fibres connected to the connection means. In order to simplify handling of optical fibre ribbons, so-called fibre ribbons, an optical connection means with an integrated cross-connection (2) has been produced with which component optical fibres (3) connected to the component can be rearranged such as cross-connected and connected via an interface (4). With an optical cross-connection of the "sidings" type integrated with a so-called MT-connector interface from for example a four-fibre transmitter array and a four-fibre receiver array an eight-fibre MT-connector interface with alternate transmitter respective receiver fibres next to each other can be obtained.

Description: CONNECTION MEANS FOR OPTICAL FIBRES TECHNICAL FIELD The present invention relates to an optical connection means arranged to be able to rearrange and connect optical fibres connected to the connection means. STATE OF THE ART From EP - 0 458 608 Al is known a connecting means for optical fibres having an integrated optical circuit which permits a reconfiguration of an optical system in the connection means. DESCRIPTION OF THE INVENTION In order to simplify the handling of optical fibre ribbons, so called fibre ribbons, a component, an optical connection means, a so called MT-connector with integrated cross-connections has been developed, with which component optical fibres connected to the component can be rearranged e.g. cross-connected and connected via an interface. The invention will be described more closely with the help of preferred embodiments and with reference to the accompanying figures. Today developments are heading towards more cost effective solutions at the circuit board level, e.g. four transmitters such as laser transmitters or four receivers can be built together on a single chip, a so called array. Such chips in turn can be encapsulated in a single capsule and in this case a four channel array transmitter or receiver can be obtained well packaged for mounting on a circuit board. During allocation to a subscriber it is desirable to be able to draw out a fibre from each of a transmitter and a receiver and consequently to obtain a bi-directional two- fibre link where the transmitter fibre and receiver fibre lie immediately beside each other. In order to obtain this configuration a sort of optical cross coupling of the "sidings" type is required. With such a "sidings" integrated with a so-called MT-connector interface from for example a four-fibre transmitter array and a four-fibre receiver array an eight-fibre MT-connection interface can be obtained with alternating transmitter respective receiver fibres next to each other. The cross connecting itself - "sidings " - can either be integrated completely in the connector itself or can be inside a lengthened break protection in direct connection to the connector. DESCRIPTION OF THE FIGURES Figure 1 shows simplified, partially sectional, a connecting means according to the invention of the eight-fibre MT-connector type with an integrated cross-coupling and an integrated eight-fibre ribbon. Figure 2 shows simplified how the eight-fibre ribbon from the connector in Figure 1 is splitable to 2 x 4 fibre ribbons. Figure 3 shows simplified the MT-connector in Figure 1 from a second side. Figure 4 shows simplified an alternative embodiment of an eight-fibre MT- connector according to the invention with an integrated cross-connection and with an MT-connector interface at both ends. PREFERRED EMBODIMENTS The optical connection means 1 can, like in Figure 1 , be an eight-fibre MT- connector, essentially consisting of a plastic casing surrounding the rearranged optical fibres like the cross-connected optical fibres 2, and having the free optical fibre ends 3 of the optical fibres connected to the plastic casing on one side and an optical fibre interface 4 on the other side of the connection means. The optical fibre ribbon ends can consequently be connected to the optical fibre interface 4 on the connection means and reconfigured or cross-connected output optical fibres can be obtained from the connecting means. Figure 1 shows simplified how an eight-fibre MT-connector with the integrated optical cross-connection 2 can appear. The placement of the integrated cross- connection 2 depends on the existing space in the casing of the connector, if the cross-connection of the optical fibres is glued into the connector or if the connector is moulded directly onto the optical fibres and the cross-connection, but does not form any limitation and four- equally 12-optical fibres can be comprised in the concept according to the above. In the figure a break protection 5 connected to the MT-connector on the front side and an interface 4 with free optical fibre ends on the rear side are also shown. The connector also has parallel circular guide holes 6 and 7 for the accurate alignment and fastening of the connector with the guide pins on a contact connector. Figure 2 shows how the input eight-fibre ribbon has been divided into 2 x 4 fibres/four- fibre ribbons 8 and 9 where one of the four-fibre ribbons 8 is intended to be connected to a four-channel array receiver module and the other four-fibre ribbon 9 is intended to be connected to a four-channel array transmitter module. In figure 3 the MT-connector is shown from the other side 10 with the so called MT- 8 connector interface 4 where alternate fibres are transmitters and alternate fibres are receivers. Figure 4 shows an alternative embodiment of a connection means 1 1 according to the invention with an integrated cross-connection 13 and with MT-connection interfaces 14 and 15 at both ends. With this connection means a fibre ribbon with an MT-connection interface is connected to the connection means whereby the connected optical fibres will be cross-connected in the connection means and during connection to e.g. a four-channel transceiver capsule with an MT-8 interface dividing up into a transmitter side and a receiver side can be obtained. The connection means can be aligned with its guide holes 16 and 17 with guide pins/guide pegs and fastened onto e.g. the transceiver capsule with some type of snap fastening or metal plate or the like. A cross-connecting component according to the above with an MT-connector interface at each end and with integrated cross- connection can be manufactured through direct moulding of the connector body around the cross-connected fibres. The use of fibre ribbons in combination with ribbon welding and optical connection means simplifies the work considerably during the installation of fibre optical networks. It is especially important in access networks where the cost determines when the optical fibre can be drawn all the way home to the subscriber (FTTH, Fibre To The Home). It is therefore desirable to be able to retain the fibre ribbon undivided even during cross-connection or other rearranging of the optical fibres. The use of the optical connection means with fibre ribbons is advantageous when for example there is a requirement for cross-connection or other rearranging of signals from transmitter- and receiver arrays on an electronic board. An optical connection means according to the invention can be manufactured starting from a suitable number of fibre ribbons one end of which have been joined together, liberated and rearranged e.g. cross-connected. The joined-together and rearranged optical fibres are fixed in the connection means through for example baking- in in plastic, whereby the cross-sectional surfaces of the fibre ends in the interface form the optical interface of the fibre end surfaces of the connected fibre ribbons. A fibre organiser can be used to organise the optical fibres in the optical connection means. The cross-connection zone, mixing point or weave zone formed can then be encapsulated between two casings possibly filled with an elastic material. The invention is naturally not limited to the embodiments described above and shown in the drawings but can be modified within the scope of the accompanying patent claims.

Claims: CLAIMS 1. Optical connection means arranged in order to be able to rearrange and connect optical fibres connected to the connection means, characterised in that the rearranging, for example a cross-connection (2,13) is integrated with the connection means (1, 11) in its casing wherein the first optical fibres connected to the connection means are rearranged such as cross-connected with the connection means before connection to other optical fibres. 2. Optical connection means according to claim 1, characterised in that an outgoing optical fibre interface (4, 15) is arranged on the output side like an MT-connection interface. 3. Optical connection means according to claim 1, characterised in that an input optical fibre interface (14) is arranged on the input side like an MT-connection interface. 4. Optical connection means according to claim 1, characterised in that both on the input side and the output side are arranged optical fibre interfaces (14, 15) of MT- connector interface type. 5. Optical connection means according to any of the claims 1-5, characterised in that the rearranged such as cross-connected optical fibres (2, 13) are glued fast into the connection means. 6. Optical connection means according to any of the claims 1-5, characterised in that the rearranged such as cross-connected optical fibres (2, 13) are moulded into the connection means.

Inventors: ENGSTRAND JAN-AAKE, MOLL HANS-CHRISTER, ENGSTRAND, JAN-AAKE, MOLL, HANS-CHRISTER
Applicants: ERICSSON TELEFON AB L M, TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Application year: 1998
Main classification: G02B6
IPC codes: G02B6