Distributed passive optical networks
View Patent ↗A passive optical network includes one or more multi-service terminals each having a housing and a plurality of ruggedized plug-receiving distribution ports accessible from outside the housing. The multi-service terminals also each include an optical power splitter or wave division multiplexer for splitting an optical signal and directing the split signal to the plug-receiving distribution ports. Some of the multi-service terminals provide a different power split ratio from others of the multi-service terminals.
1. A cascading distribution terminal arrangement comprising:
a first distribution terminal defining an interior, the first distribution terminal including an optical splitter arrangement disposed within the interior, the optical splitter arrangement including a 1-by-2 optical power splitter and a second optical power splitter having a higher split ratio than the 1-by-2 optical power splitter, a first output line of the 1-by-2 optical power splitter being routed to a first single-fiber ruggedized output port to be accessible from an exterior of the fiber distribution terminal, a second output line of the 1-by-2 optical power splitter being routed to the second optical power splitter, optical signals split by the second optical power splitter being routed to a plurality of single-fiber ruggedized output ports that are separate from the first single-fiber ruggedized output port, the single-fiber ruggedized output ports being accessible from an exterior of the fiber distribution terminal;
a second distribution terminal defining a ruggedized input port and a plurality of ruggedized output ports that are accessible from an exterior of the second distribution terminal; and
a cascade fiber routed between the first single-fiber ruggedized output port of the first distribution terminal and the ruggedized input port of the second distribution terminal.
2. The cascading distribution terminal arrangement of claim 1 , further comprising a plurality of subscriber fibers, each subscriber fiber being routed from one of the first and second distribution terminals to a respective subscriber location.
3. The cascading distribution terminal arrangement of claim 1 , wherein the second distribution terminal includes an optical power splitter having a same split ratio as the second optical power splitter.
4. A method of providing a distributed passive optical network comprising:
deploying a network framework at feeder locations and distribution locations within a geographical area on a first day, wherein deploying the network framework includes laying conduit between the feeder and distribution locations, routing optical fibers along the conduits between the feeder locations and the distribution locations, and storing ends of the optical fibers at respective handholes and/or pedestals, the ends being connectorized; and
subsequently incrementally installing distribution terminals on a second day that is after the first day, wherein installing the distribution terminals on a second day that is after optical fibers to the distribution terminals.
5. The method of claim 4 , wherein connecting the ends of the optical fibers to the distribution terminals comprises plugging the connectorized ends of the optical fibers into ruggedized adapters of the distribution terminals.
6. The method of claim 4 , wherein the conduits are laid in small bores through streets.
7. The method of claim 4 , further comprising routing a drop fiber through one of the conduits to one of the pedestals and/or handholes.
8. The method of claim 7 , wherein excess length of the drop fiber is stored in the pedestal and/or handhole.
9. The method of claim 7 , wherein a connectorized end of the drop fiber is initially stored in the pedestal and/or handhole during deployment of the network framework and is subsequently plugged into a respective one of the distribution terminals during installation of the distribution terminal.
10. The method of claim 4 , wherein subsequently incrementally installing distribution terminals comprises installing a drop terminal having a plurality of ports, wherein a first of the ports of the drop terminal receives optical signals having a first split ratio and wherein others of the ports of the drop terminal receive optical signals having a second split ratio that is higher than the first split ratio.
11. The method of claim 10 , wherein the first port of the drop terminal is a single-fiber port.
12. The method of claim 10 , further comprising an optical line routed from the first port to a handhole.
13. The method of claim 12 , wherein the optical line is routed beneath a street.
14. The method of claim 12 , further comprising subsequently installing a second terminal holding an optical splitter and coupling the optical line to an input of the optical splitter.
15. The method of claim 10 , further comprising subsequently upgrading the distributed passive optical network by replacing the drop terminal with a wave division multiplexer terminal.
16. A cascading distribution system comprising:
a feeder terminal housing a splitter arrangement in which a distribution fiber is split into at least two drop fibers;
a first distribution terminal having a ruggedized input port, a plurality of ruggedized output ports, and an optical power splitter arrangement, the ruggedized input port receiving a first of the at least two drop fibers from the feeder terminal, the optical splitter arrangement including a 1-by-2 optical power splitter and a second optical power splitter having a higher split ratio than the 1-by-2 optical power splitter, a first output line of the 1-by-2 optical power splitter being routed to a first single-fiber ruggedized output port to be accessible from an exterior of the first distribution terminal, a second output line of the 1-by-2 optical power splitter being routed to the second optical power splitter, optical signals split by the second optical power splitter being routed to a plurality of single-fiber ruggedized output ports that are separate from the first single-fiber ruggedized output port, the single-fiber ruggedized output ports being accessible from an exterior of the first distribution terminal;
a second distribution terminal having a ruggedized input port, a plurality of ruggedized output ports, and a third optical power splitter, the ruggedized input port receiving signals from the first single-fiber ruggedized output port of the first distribution terminal, the third optical power splitter having a common split ratio with the second optical power splitter of the first distribution terminal; and
a third distribution terminal having a ruggedized input port, a plurality of ruggedized output ports, and a fourth optical power splitter, the ruggedized input port receiving a second of the at least two drop fibers from the feeder terminal, the fourth optical power splitter splitting optical signals carried over the second drop fiber to the ruggedized output ports at a split ratio that is double the common split ratio of the second and third optical power splitters.