Fiber optic transmission with fiber amplifiers and supervisory signals
First Claim
1. A method of providing supervisory signals to amplifiers of a fiber optic system, the fiber optic system carrying traffic signals at one or more traffic signal carrier wavelengths from a first terminal station of the fiber optic system, wherein the traffic signals are amplified by the amplifiers so that the traffic signals are maintained in strength along the fiber optic cable system for detection at a second terminal station, characterized in that a carrier wavelength different from the one or more carrier wavelengths used for the traffic signals is employed to carry a supervisory signal but no traffic signals, wherein the fiber optic system is adapted such that the supervisory signal is amplified such that the supervisory signal is maintained in strength along the fiber optic system by the same the amplifiers amplifying the traffic signals, and wherein supervisory information is provided on its carrier wavelength by modulation at a frequency substantially lower than that of a traffic bit rate for detection by detectors located at the amplifiers.
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Accused Products
Abstract
Methods of providing supervising signals to amplifiers of a fiber optic system are described. In the system, traffic signals are carried at one or more traffic signal carrier wavelengths and are amplified by the amplifiers so that they are maintained in strength. Supervisory signals are provided either at two different carrier wavelengths, or at a single carrier wavelength which is, although different from the traffic signal carrier wavelengths, such that the supervisory signal is maintained in strength by the same amplifiers. Supervisory information is provided on the supervisory signal by modulation at a frequency substantially lower than that of a traffic bit rate for detection by detectors located at the amplifiers. A fiber optic system is also described which is adapted to utilize this method.
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Citations
20 Claims
- 1. A method of providing supervisory signals to amplifiers of a fiber optic system, the fiber optic system carrying traffic signals at one or more traffic signal carrier wavelengths from a first terminal station of the fiber optic system, wherein the traffic signals are amplified by the amplifiers so that the traffic signals are maintained in strength along the fiber optic cable system for detection at a second terminal station, characterized in that a carrier wavelength different from the one or more carrier wavelengths used for the traffic signals is employed to carry a supervisory signal but no traffic signals, wherein the fiber optic system is adapted such that the supervisory signal is amplified such that the supervisory signal is maintained in strength along the fiber optic system by the same the amplifiers amplifying the traffic signals, and wherein supervisory information is provided on its carrier wavelength by modulation at a frequency substantially lower than that of a traffic bit rate for detection by detectors located at the amplifiers.
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9. A fiber optic system comprising:
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a first terminal station (1);
a second terminal station (2) connected to the first terminal station by fiber optic cable (5);
means for providing traffic signals (1, 2, 7, 8) at one or more traffic signal carrier wavelengths at the first terminal station (1);
means for providing at the first terminal (1) a supervisory signal (3, 4, 5, 6) at a non traffic carrying carrier wavelengths different from the one or more traffic signal carrier wavelengths and for modulating that carrier with the supervisory signal; and
the fiber optic cable (5) comprises a plurality of amplifiers (11), the amplifiers of the plurality of amplifiers being adapted to maintain in strength along the fiber optic system both the traffic signals (1, 2, 7, 8) and the supervisory signal, and wherein the amplifiers (11) have associated therewith detectors (17a, 17b) adapted to detect supervisory information provided by modulation of the supervisory signal at a frequency significantly lower than that of a traffic signal bit rate. - View Dependent Claims (10, 11, 12, 19, 20)
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Specification