Optical waveguides – Optical transmission cable
Reexamination Certificate
1999-06-24
2002-07-30
Font, Frank G. (Department: 2877)
Optical waveguides
Optical transmission cable
Reexamination Certificate
active
06427042
ABSTRACT:
The present invention relates to a method and an apparatus for providing a telecommunication service via optical fibre, and in particular to a method and an apparatus that may be used to provide a telecommunication service to customer premises cost-effectively at low penetrations using blown optical fibre.
BACKGROUND TO THE INVENTION
For many years there has been much interest in the telecoms industry in FTTH/SOHO (Fibre to the Home/Small Office/Home Office), as the alternate method of providing high bandwidth connections to customers. The majority of telecommunications operators have conducted field trials to establish the most appropriate optical technology to suit their requirements, and have also collaborated to determine specifications for potential products.
FIG. 1
shows a conventional method for distributing optical fibre cables to customers on a PON (Passive Optical Network) in the form of an overhead distribution network (
110
), where the end distribution fibre cables (sometimes known as lateral cables)(
112
c
) are supported on poles (
114
). Multi fibre cable (
112
a
) extends from the OLT (Optical Line Terminator) located in a central office via a FDI (Feeder or Fibre Distribution Interface), containing optical splitters, to the main distribution area. The network (
110
) is extended across the main distribution area using collector cables (
112
b
) and connected by splices at a main splice box (
50
) to the lateral cables(
112
c
).
At each pole (
114
) where there is a requirement for a connection to a customer premises (a customer ‘drop’) a fibre closure (or cable entry box) (
116
) is installed. This allows the lateral fibre cables (
112
c
) to be accessed so that a connection may be made to the relevant fibre drop cable (
118
) which connects the customer to the distribution network. Such a connection may consist of one or more fibres connected to an ONU (Optical Network Unit). The ONU is in turn connected to the apparatus requiring the broadband overlay services eg. a television (
132
) or a computer (
134
). Unused lateral cable ends may simply be blanked-off (
117
).
FIG. 2
shows in more detail the connection from the street distribution cable (
112
c
) to the customer's premises, in this instance a home. When connecting a fibre drop (
118
) to cables (
112
c
), the latter is normally ‘broken into’ through the use of a cable entry box (
120
). The optical fibres to be ‘dropped’ are separated from the main cable and cut and then spliced on to a tail cable (
122
). The tail cable (
122
) typically extends from the cable entry box to the splice box (
124
), which may also be pole mounted. In some instances the cable entry box is combined with the splice box.
When a new customer requires a drop, the fibre drop cable (
118
) is connected to the fibre distribution network at the splice box (
124
) as shown in FIG.
3
. An individual splice (
128
) is required for connecting each fibre drop cable to the respective fibre (
119
) of the tail cable. Seals (
126
) and blanking pieces (
130
) for unused fibre drop cable entry holes to the splice box, together with clamps (not shown) are used to ensure that the splice box is sealed from environmental conditions.
Connections to the network are normally made on a customer by customer basis. Splicing fibre cable is time consuming and requires a high craft skill base and is therefore relatively expensive. It is therefore expensive to provide the extensive network infrastructure over large areas so that individual customers may be easily connected to a local cable when required, e.g. providing the basic network to the street distribution level. Equally, connecting the customer's drop cable to the network requires a considerable amount of labour that also results in a high per-line cost. The costs are particularly significant at low customer penetrations, where the high upfront cost of installing the complete network infrastructure may only be shared across a few customers.
It is an object of the present invention to address at least one of the above-mentioned problems of the prior art. In particular, it would be desirable to address the problems associated with the high cost of the infrastructure and the time taken to connect customers to the network due to, for example, splicing at poles.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a method of provisioning for a telecommunications service via optical fibre to customers' premises, the method comprising;
a) installing a first optical fibre tube between a main distribution site (MDS) and a first-customer proximity site (CPS
1
) external to customer premises,
b) installing a first tube extension between the first tube at the CPS
1
and the first customer's premises,
c) installing an optical fibre along the first tube and the first tube extension, and
d) connecting the fibre at the MDS to make available the telecommunication service for the first customer.
Preferably, the installing of the fibre is selected from the group of blowing, pushing and pulling said fibre.
In another aspect, the present invention provides provisioning for a telecommunications service by the method of claim 4 or claim 5.
Preferably said first optical fibre tube is a multi bore tube, and said optical fibre is installed along a single bore of said multi bore tube.
The fibre connection at the MDS may be a splice.
Preferably, a second tube extension is installed, coupling between a further bore of the first tube and a second customer's premises,
optical fibre is installed along the second bore and the second tube extension, and the fibre is connected at the MDS to make available the telecommunications service for the second customer.
Preferably, a second multi bore optical fibre tube is installed between a MDS and a further customer proximity site (CPS
2
) external to customer premises,
a further tube extension is installed coupled between a bore of the second tube at the CPS
2
and a further customer's premises,
an optical fibre is installed along the bore of the second tube and the further tube extension, and
the fibre is connected at the MDS to make available the telecommunications service for the further customer.
In another aspect, the present invention provides an apparatus for use in a optical fibre ducting system, said apparatus comprising
a housing;
a first aperture in said housing, said first aperture being arranged to receive a multi-bore optical fibre duct comprising at least two bores;
at least two further apertures in said housing, said further apertures each being arranged to receive a respective optical fibre duct; and
at least one connection means for connection of an individual bore of said multi-bore duct to at least one of said respective fibre ducts.
This connecting apparatus removes the need to splice adjacent to the customer premises (eg. at the pole top), hence reducing the number of splice required and resulting in a save in costs.
Preferably, said apparatus further comprises at least one closure means, said closure means being arranged to be removably fitted to said housing such that when located on said housing said closure means seals one of said apertures for prevention of ingress of undesired substances into the housing.
Preferably, the apparatus further comprises at least one clamp for securely locating at least one of the said ducts to said housing.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying drawings.
REFERENCES:
patent: 5363432 (1994-11-01), Martin et al.
patent: 5696864 (1997-12-01), Smith et al.
Dyer Michael Philip
Dyke Peter John
Parry Mark James
Font Frank G.
Lee Andrew H.
Lee Mann Smith McWilliams Sweeney & Ohlson
Nortel Networks Limited
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