Single fiber duplex optical transport
AssigneePivotal Decisions LLC
InventorsMichael H. Eiselt, Lara Garrett, Marvin R. Young
Life of this patent
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Abstract
The invention pertains to optical fiber transmission systems, and is particularly relevant to optical transport systems employing optical amplifiers. In particular the invention teaches an apparatus and method that allows cost effective co-directional operation of an optical amplifier to support full duplex traffic on a single fiber, and the design of an optical fiber transmission system based on this optical amplifier technology.
Claims48
An inline optical amplifier station for an optical system transporting a bidirectional optical signal comprising:
- A first optical coupler/decoupler for separating an unamplified eastbound signal from a first bidirectional signal and for combining an amplified westbound signal into the first bidirectional signal;
- A second optical coupler/decoupler for separating an unamplified westbound signal from a second bidirectional signal and for combining an amplified eastbound signal into the second bidirectional signal;
- A first variable optical attenuator connected to the unamplified eastbound signal and to an optical coupler;
- A second variable optical attenuator connected to the unamplified westbound signal and to the optical coupler;
- The optical coupler combining the unamplified eastbound signal with the unamplified westbound signal into a combined unamplified signal;
- The optical coupler operatively connected to an optical amplifier;
- The optical amplifier converting the combined unamplified signal into a combined amplified signal;
- and
- The optical amplifier operatively connected to an optical decoupler decoupling the combined amplified signal into the amplified eastbound signal and the amplified westbound signal.
A method for amplifying an eastbound signal and a westbound signal in a single fiber optical transport system comprising the steps of:
- isolating an unamplified eastbound signal;
- isolating an unamplified westbound signal;
- power matching the unamplified eastbound signal and the unamplified westbound signal;
- combining the power matched signals;
- amplifying the power matched signals;
- isolating an amplified eastbound signal;
- and
- isolating an amplified westbound signal.
In an A-Z/Z-A bi-directional optical transport system having segments comprising a plurality of ordered spans separated by and connected to a corresponding series of ordered bi-directional DCMs and terminated by a first and second co-directional DCM having A-Z and Z-A compensators, a method of correcting for the dispersion of the spans comprising the steps of:
- A. Adjusting each but the last of the co-directional DCMs to compensate for the dispersion of the corresponding previous span;
- B. Adjusting the last co-directional DCM to compensate for the dispersion of the corresponding previous span, plus the dispersion of the corresponding subsequent span, minus the average dispersion of all the spans;
- C. Adjusting the A-Z compensator of the second bi-directional DCM to compensate for the dispersion of the corresponding previous span;
- and
- D. Adjusting the Z-A compensator of the first bi-directional DCM to compensate for the average of the bi-directional DCMs, plus the average dispersion of all the spans.
In a bi-directional optical transport system consisting of segments having a series of ordered spans separated by and connected to a corresponding series of ordered bi-directional DCMs and terminated at a first and second co-directional DCM each having an A-Z and Z-A compensator, a method of correcting for the dispersion of the spans comprising the steps of:
- A. Adjusting each but the last of the co-directional DCMs and the A-Z compensator of the second bi-directional DCM according to the following equation:
- Dcomp=DN−1+CON−1−DUC
- Where:
- Dcomp is the dispersion value to be compensated;
- DN−1 is the dispersion value of the previous span;
- DUC is the per-span dispersion under-compensation;
- and
- CON−1 is the carry over dispersion value of the previous span;
- B. Adjusting the compensation of the last co-directional DCM according to the equation:
- 4 D ′ comp = ( D N - 1 ′ + D ′ N - 1 N ∑ i = 1 N D i ) + CO ′ N - 1
- Where:
- Dcomp′ is the dispersion value to be compensated;
- DN−1′ is the dispersion value of the previous span;
- CON−1′ is the carry over dispersion value of the previous span;
- N′ is the number of ordered spans in the segment;
- Di is the dispersion value of each ordered span in the segment;
- and
- C. Adjusting the compensation of the Z-A compensator of the first bi-directional DCM according to the equation:
- 5 D ″ comp = ∑ i = 1 N 1 D N + ∑ i = 1 N D compN + CO N + 1
- Where:
- Dcomp is the dispersion value to be compensated;
- D1 is the dispersion compensation value of the A-Z compensator of the first bi-directional DCM;
- D2 through DN are the dispersion compensation values of each co-directional DCM;
- DcompN is the dispersion of each span of the plurality;
- and
- CON+1 is the carry over from the co-directional DCM following to the last span of the segment.
In an A-Z/Z-A bidirectional optical transport system comprising ordered spans separated by and connected to a corresponding series of ordered bi-directional DCMs and terminated by a first and second co-directional DCM having A-Z and Z-A compensators, a method of correcting for the dispersion of the spans comprising the steps of:
- A. Adjusting each but the co-directional DCMs to compensate for the dispersion of the corresponding previous span;
- B. Adjusting the last co-directional DCM to compensate for the dispersion of the corresponding previous span, plus the dispersion of the corresponding subsequent span, minus the average dispersion of all the spans;
- C. Adjusting the A-Z compensator of the second bi-directional DCM to compensate for the dispersion of the corresponding previous span;
- and
- D. Adjusting the Z-A compensator of the first bi-directional DCM to compensate for the average of the bi-directional DCMs, plus the average dispersion of all the spans.
Dependencies are inferred from the claim text.