Bi-directional optical transmission system, and master and slave stations used therefor
First Claim
1. A system for bi-directional optical communications between a master station and a plurality of slave stations, wherein the master station and the slave stations are connected to each other via a single optical fiber, the master station transmits a downstream optical signal to each of the slave stations via the single optical fiber, and each of the slave stations transmits an upstream optical signal to the master station via the single optical fiber, the master station includes:
- a first electrical-optical converter for converting an electrical signal to the downstream optical signal;
a first optical-electrical converter for converting the upstream optical signal to an electrical signal; and
a first optical exchange element, provided between the single optical fiber, and the first electrical-optical converter and the first optical-electrical converter, for outputting the downstream optical signal supplied by the first electrical-optical converter to the single optical fiber and outputting the upstream optical signal transmitted through the single optical fiber to the first optical-electrical converter, and each of the slave stations includes;
a second electrical-optical converter for converting an electrical signal to the upstream optical signal;
a second optical-electrical converter for converting the downstream optical signal to an electrical signal; and
a second optical exchange element, provided between the single optical fiber, and the second electrical-optical converter and the second optical-electrical converter, for outputting the upstream optical signal supplied by the second electrical-optical converter to the single optical fiber and outputting the downstream optical signal transmitted through the single optical fiber to the second optical-electrical converter.
1 Assignment
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Accused Products
Abstract
An object of the present invention is to provide a bi-directional optical transmission system wherein a single optical fiber is shared by upstream and downstream systems, thereby eliminating the need for providing an additional optical fiber and reducing the number of maintenance operations. A master station 400 for outputting a downstream optical signal is connected via an optical transmission path 200 to slave stations 500a-500c each for outputting an upstream optical signal. The optical transmission path 200 includes a single optical fiber connecting at one end to the master station 400, and optical branching units 202a, 202b branching the single optical fiber for connection to the slave stations. The master station 400 includes an optical passive unit 405 which supplies an upstream optical signal coming through the single optical fiber only to an optical-electrical converter 404 and supplies a downstream optical signal output from an electrical-optical converter 403 only to the single optical fiber. Each slave station includes an optical passive unit 505 which supplies a downstream optical signal coming through the single optical fiber only to an optical-electrical converter 504 and supplies an upstream optical signal output from an electrical-optical converter 503 only to the single optical fiber.
181 Citations
44 Claims
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1. A system for bi-directional optical communications between a master station and a plurality of slave stations, wherein
the master station and the slave stations are connected to each other via a single optical fiber, the master station transmits a downstream optical signal to each of the slave stations via the single optical fiber, and each of the slave stations transmits an upstream optical signal to the master station via the single optical fiber, the master station includes: -
a first electrical-optical converter for converting an electrical signal to the downstream optical signal;
a first optical-electrical converter for converting the upstream optical signal to an electrical signal; and
a first optical exchange element, provided between the single optical fiber, and the first electrical-optical converter and the first optical-electrical converter, for outputting the downstream optical signal supplied by the first electrical-optical converter to the single optical fiber and outputting the upstream optical signal transmitted through the single optical fiber to the first optical-electrical converter, and each of the slave stations includes;
a second electrical-optical converter for converting an electrical signal to the upstream optical signal;
a second optical-electrical converter for converting the downstream optical signal to an electrical signal; and
a second optical exchange element, provided between the single optical fiber, and the second electrical-optical converter and the second optical-electrical converter, for outputting the upstream optical signal supplied by the second electrical-optical converter to the single optical fiber and outputting the downstream optical signal transmitted through the single optical fiber to the second optical-electrical converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A system for bi-directional optical communications between a master station and a plurality of slave stations located on a plurality of groups, wherein
a radio communications area of one group overlaps with another radio communications area of another group, the master station and each of the slave stations of a same group are connected to each other via a single optical fiber, the master station transmits a downstream optical signal to each of the slave stations of the same group via the single optical fiber, and each of the slave stations of the same group transmits an upstream optical signal to the master station via the single optical fiber, the master station includes, for each of the groups, a first electrical-optical converter for converting an electrical signal to the downstream optical signal; -
a first optical-electrical converter for converting the upstream optical signal to an electrical signal; and
a first optical exchange element, provided between the single optical fiber, and the first electrical-optical converter and the first optical-electrical converter, for outputting the downstream optical signal supplied by the first electrical-optical converter to the single optical fiber and outputting the upstream optical signal transmitted through the single optical fiber to the first optical-electrical converter, and each of the slave stations includes;
a second electrical-optical converter for converting an electrical signal to the upstream optical signal;
a second optical-electrical converter for converting the downstream optical signal to an electrical signal; and
a second optical exchange element, provided between the single optical fiber, and the second electrical-optical converter and the second optical-electrical converter, for outputting the upstream optical signal supplied by the second electrical-optical converter to the single optical fiber and outputting the downstream optical signal transmitted through the single optical fiber to the second optical-electrical converter.
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29. A master station for bi-directional optical communications with a plurality of slave stations,
the master station being connected to each of the slave stations via a single optical fiber, the master station transmitting a downstream optical signal to each of the slave stations via the single optical fiber, and receiving an upstream optical signal transmitted from each of the slave stations via the single optical fiber, and the master station comprising: -
an electrical-optical converter for converting an electrical signal to the downstream optical signal;
an optical-electrical converter for converting the upstream optical signal into an electrical signal;
an optical exchange element provided between the single optical fiber, and the electrical-optical converter and the optical-electrical converter, for outputting the upstream optical signal supplied by the electrical-optical converter to the single optical fiber and outputting the downstream optical signal transmitted through the single optical fiber to the optical-electrical converter;
a signal level adjusting circuit for adjusting an amplitude of an electrical signal, and outputting the amplitude-adjusted electrical signal;
a delay adjusting circuit for adjusting a phase of the electrical signal output from the signal level adjusting circuit, and outputting the phase-adjusted electrical signal; and
a combiner for combing the electrical signal output from the delay adjusting circuit and the electrical signal output from the optical-electrical converter. - View Dependent Claims (30, 31)
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32. A slave station for bi-directional optical communications with a master station,
the slave station being connected to the master station via a single optical fiber, the slave station receiving a downstream optical signal transmitted from the master station via the single optical fiber, and transmitting an upstream optical signal to the master station via the single optical fiber, and the slave station comprising: -
an electrical-optical converter for converting an electrical signal to the upstream optical signal;
an optical-electrical converter for converting the downstream optical signal into an electrical signal;
an optical exchange element provided between the single optical fiber, and the electrical-optical converter and the optical-electrical converter, for outputting the upstream optical signal supplied by the electrical-optical converter to the single optical fiber and outputting the downstream optical signal transmitted through the single optical fiber to the optical-electrical converter;
a signal level adjusting circuit for adjusting an amplitude of an electrical signal, and outputting the amplitude-adjusted electrical signal;
a delay adjusting circuit for adjusting a phase of the electrical signal output from the signal level adjusting circuit, and outputting the phase-adjusted electrical signal; and
a combiner for combing the electrical signal output from the delay adjusting circuit and the electrical signal output from the optical-electrical converter. - View Dependent Claims (33, 34)
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35. A system for bi-directional optical communications between a master station and a plurality of slave stations, wherein
the master station and the slave stations are connected to each other via a single optical fiber, the slave stations are assigned different wavelengths of downstream optical signals transmitted from the master station to the slave stations, the slave stations are assigned different wavelength of upstream optical signals transmitted from the slave stations to the master station, the master station transmits the downstream optical signals to the respective slave stations via the single optical fiber, and the slave stations respectively transmit the upstream optical signals to the master station via the single optical fiber, the master station includes: -
a plurality of first electrical-optical converters, provided correspondingly to the slave stations, each for converting an electrical signal to a downstream optical signal having a wavelength assigned to a corresponding slave station;
a plurality of optical-electrical converters, provided correspondingly to the slave stations, each for converting an upstream optical signal supplied by a corresponding slave station to an electrical signal; and
a wavelength multiplexer/demultiplexer for wavelength-multiplexing the downstream optical signals supplied by the first electrical-optical converters and outputting a multiplexed signal to the single optical fiber, and for wavelength-demultiplexing the upstream optical signals transmitted through the single optical fiber and outputting optical signals correspondingly in wavelength to the first optical-electrical converters, and each of the slave stations includes;
a second electric-optical converter for converting an electrical signal to an upstream optical signal having a wavelength assigned to the slave station;
a second optical-electrical converter for converting the downstream optical signal to an electrical signal; and
an optical add/drop unit, provided between the single optical fiber, and the second electrical-optical converter and the second optical-electrical converter, for outputting the upstream optical signal supplied by the second electrical-optical converter to the single optical fiber and outputting only a downstream optical signal having a wavelength assigned to the slave station from out of the downstream optical signals transmitted through the single optical fiber to the second optical-electrical converter. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44)
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Specification