Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Patent
1991-08-12
1994-08-23
Pascal, Leslie
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
359121, 359139, 359178, H04B 1020
Patent
active
053412320
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a star-shaped network for data transmission between stations comprising star couplers arranged at the branchings of the network.
BACKGROUND OF THE INVENTION
Networks for data communication may be equipped with passive and/or active star couplers between communication channels,
Passive star couplers are used in optical communication networks. A passive star coupler is defined as having no amplifying or regenerating components therefore needing no electrical energy. The power of the optical flow of data is split by optical means. A star coupler is provided with ports, each port is provided with an input and an output. The star coupler is provided with as many inputs as outputs.
Each single station of the network is connected by two light waveguides labeled LWL in the following, to the star coupler. One LWL is transporting data to be received while the other LWL is transporting data to be transmitted by the station. A pair of these LWLs is associated to a port of the star coupler. The number of ports of the star coupler and the number of stations of the network are the same. The signals having power P and supplied to the input of a port by a LWL are split into nearly equal amounts by the order of magnitude of P
(without considering internal coupling Losses) to the outputs of the star coupler. From the outputs the optical signals are transmitted on one of the n LWL to a receiver installed in one of the n stations of the network.
The output of that port whose input receives incoming signals is provided by the same amount of power as the outputs of all other ports, Star couplers of this type are designated "symmetrical" in the following if
1. The number of inputs is equal to the number of outputs, and
2. the optical power supplied to the input of any port X is split nearly equally among the outputs of all ports i.e. to the output of the port X too.
It is essential that the maximum working range of transmission i.e. the maximum distance between two stations, Lmax, depends on the number of ports of the star coupler, i.e. the number of stations of the network.
For optical data networks symmetrical active star couplers may be used too, the definition of symmetry mentioned above is equally valid. Such a star coupler is provided with n ports, each port being provided by one input (with an optical receiver) and one output (with an optical transmitter). Therefore the star coupler is provided with as many inputs as outputs. A star coupler as mentioned above is defined in accordance with the corresponding passive star coupler as a symmetrical active star coupler.
The star coupler as mentioned above is symmetrical because it is provided by as many inputs as outputs and because each output including the output of that port whose input receives the optical signals is fed by the same amount of signal power. The star coupler is active because all received optical signals are converted to electrical signals, regenerated with respect to Level and timing, fed to all outputs by an electronic circuit and retransferred at the outputs in optical signals and because electrical energy is required for these steps.
It is essential that the maximum working range of the network i.e. the maximum distance between two stations, Lmax, is independent of the number of ports of the star connector, i.e. the number of stations, if an active star coupler is used.
Networks may be provided with active and passive star couplers. Passive star couplers are safe against failure to a high degree.
However passive star couplers are suitable for networks with a limited range and number of stations only. Active star couplers are suitable for networks of very large working range and many stations.
Active star couplers are equipped with many optoelectronic converters and electronic circuits rendering them more expensive as compared to passive couplers in general. Moreover there are additional provisions necessary to increase safety against failure. On account of these disadvantages it is not reasonable for l
REFERENCES:
patent: 4516272 (1985-05-01), Yano
patent: 5073982 (1991-12-01), Viola
Licentia Patent-Verwaltung-GmbH
Pascal Leslie
LandOfFree
Star-shaped network for data communication between stations does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Star-shaped network for data communication between stations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Star-shaped network for data communication between stations will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-506760