Bi-directional optical transmission using dual channel bands
First Claim
1. A system for bi-directional transmission of optical signals over a single optical medium coupled between at least two nodes, said system utilizing a first optical transmission band for signals traveling in a first direction and a second optical transmission band for signals traveling in a second direction, said system comprising:
- at least a first combiner/separator unit at a first of said two nodes, said first combiner/separator including an input port, an output port and a bi-directional input/output port for coupling to said single optical medium, a first optical filter within said first combiner/separator unit coupled to each of said ports therein, said first optical filter being substantially transmissive to optical signals of said first band entering said input port and exiting on said bi-directional input/output port and said first optical filter being substantially reflective for signals of said second band entering said bi-directional input/output port and exiting on said output port; and
at least a second combiner/separator unit at a second of said two nodes, said second combiner/separator including an input port, an output port and a bi-directional input/output port coupled to said optical medium, a second optical filter within said second combiner/separator unit coupled to each of said ports therein of said second combiner/separator unit, said second optical filter being substantially transmissive to optical signals of said second band entering said input port and exiting on said bi-directional input/output port and said second optical filter being substantially reflective for signals of said first band entering said bi-directional input output port and exiting on said single direction output port,wherein said first optical filter and said second optical filter are in an alternating arrangement.
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Accused Products
Abstract
A bi-directional optical transmission system according to the present invention provides transport of x optical channels over n nodes. The system supports two-way transport of the x channels over a single fiber connecting each of the nodes in sequence. The system is advantageous in that only two optical transmission bands are utilized in order to achieve minimal loss in the separation of bands. The use of only two bands permits the utilization of low-loss wide band thin film optical filters to combine and separate the signals at each node. A reflection port of this filter is used to carry oppositely directed signals of the second band from the bi-directional fiber to an optical amplifier for the second band. An alternate arrangement of the optical filters in the two separate bands is chosen to maximize the optical performance of the overall system and significantly reduce insertion losses.
38 Citations
26 Claims
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1. A system for bi-directional transmission of optical signals over a single optical medium coupled between at least two nodes, said system utilizing a first optical transmission band for signals traveling in a first direction and a second optical transmission band for signals traveling in a second direction, said system comprising:
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at least a first combiner/separator unit at a first of said two nodes, said first combiner/separator including an input port, an output port and a bi-directional input/output port for coupling to said single optical medium, a first optical filter within said first combiner/separator unit coupled to each of said ports therein, said first optical filter being substantially transmissive to optical signals of said first band entering said input port and exiting on said bi-directional input/output port and said first optical filter being substantially reflective for signals of said second band entering said bi-directional input/output port and exiting on said output port; and at least a second combiner/separator unit at a second of said two nodes, said second combiner/separator including an input port, an output port and a bi-directional input/output port coupled to said optical medium, a second optical filter within said second combiner/separator unit coupled to each of said ports therein of said second combiner/separator unit, said second optical filter being substantially transmissive to optical signals of said second band entering said input port and exiting on said bi-directional input/output port and said second optical filter being substantially reflective for signals of said first band entering said bi-directional input output port and exiting on said single direction output port, wherein said first optical filter and said second optical filter are in an alternating arrangement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for bi-directional transmission of optical signals over a single optical fiber, said system including at least two nodes having said optical fiber coupled therebetween, said system utilizing only two distinct optical transmission bands, a single one of said bands for transmission of said optical signals in one of two directions, the other of said bands for transmission of said optical signals in the opposite direction, said system comprising:
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at least a first and second combiner/separator unit, at least one combiner/separator unit located at each of said two nodes, each said combiner/separator unit including an input port, an output port and a bi-directional input/output port for coupling to said single optical fiber, an optical filter within said combiner/separator units coupled to each of said ports, each said combiner/separator unit operable to direct optical signals entering said input port through said optical filter to said bi-directional input/output port and to reflect optical signals entering said bi-directional input/output port off of said optical filter to said output port; said optical filter in said first combiner/separator unit being substantially transmissive to a first of said two bands and substantially reflective to optical signals in said second band traveling in an opposite direction; said optical filter in said second combiner/separator unit being substantially transmissive to signals in said second band and substantially reflective for signals of said first band traveling in an opposite direction; and said first and second combiner/separator units being alternately coupled within said bi-directional transmission system such that pairs of said first and second combiner/separator units are utilized in combination, said bi-directional ports of said combiner/separator units being coupled to one another, wherein said optical filter in said first combiner/separator unit and said optical filter in said second combiner/separator unit are in an alternating arrangement. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for bi-directional transmission of optical signals over a single optical fiber coupled between two nodes, said method utilizing only two distinct optical transmission bands, a single one of said bands for transmission of said optical signals in one of two directions, the other of said bands for transmission of said optical signals in the opposite direction, said method comprising:
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providing at least a first and second combiner/separator unit, at least one combiner/separator unit located at each of said two nodes, said combiner/separator units each including an input port, an output port and a bi-directional input/output port for coupling to said single optical fiber, an optical filter within said combiner/separator units coupled to each of said ports, each of said combiner separator units operable to direct optical signals entering said input port through said optical filter to said bi-directional input/output port and to reflect optical signals entering said bi-directional input/output port off of said optical filter to said output port, said optical filter in said first combiner/separator unit being substantially transmissive to a first of said two bands and substantially reflective to optical signals in said second band traveling in an opposite direction, said optical filter in said second combiner/separator unit being substantially transmissive to signals in said second band and substantially reflective for signals of said first band traveling in an opposite direction; and alternately coupling said first and second combiner/separator units within said bi-directional transmission system such that pairs of said first and second combiner/separator units are utilized in combination, said bi-directional ports of said combiner/separator units being coupled to one another, wherein said optical filter in said first combiner/separator unit and said optical filter in said second combiner/separator unit are in an alternating arrangement. - View Dependent Claims (18)
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19. Apparatus, comprising:
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means for filtering, and means for transmitting a first signal in a first signal band from a first path onto an optical medium via said means for filtering, said means for filtering being substantially transmissive to signals in said first signal band and substantially reflective to signals in a second signal band received from said optical medium onto a path separate from said first path, wherein said means for filtering is adapted to be coupled in an alternating arrangement to a second means for filtering, said second means for filtering being substantially transmissive to said signals in said second signal band and substantially reflective to said signals in said first signal band. - View Dependent Claims (20, 21, 22, 23)
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24. Apparatus for use in a communication system of a type in which optical signals in a first signal band are transported in one direction along an optical transport medium and signals in a second signal band are transported in the opposite direction of said optical transport medium, said apparatus comprising:
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a first signal path, a second signal path, different from said first path, and an optical filter that allows the signals traveling in said one direction to flow from said first path onto said transport medium and that reflects the signals traveling in said opposite direction onto said second path, wherein said optical filter is adapted to be coupled in an alternating arrangement to a second optical filter, said second optical filter allows said signals in said second signal band to flow onto said transport medium and reflects said signals in said first signal band. - View Dependent Claims (25, 26)
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Specification