Optical: systems and elements – Optical amplifier – Correction of deleterious effects
Reexamination Certificate
1998-07-15
2001-08-07
Moskowitz, Nelson (Department: 3662)
Optical: systems and elements
Optical amplifier
Correction of deleterious effects
C359S199200, C359S341200, C359S341300
Reexamination Certificate
active
06271962
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system of controlling a wavelength division multiplexed optical amplifier and a method of its operation, and more particularly, to a system of controlling a wavelength division multiplexed optical amplifier for supervising the state of the optical multiplexer and controlling an amplification factor using a supervising channel and a control method for.
2. Description of the Related Art
With the development of the erbium doped fiber amplifier, a type of optical amplifier, enormous growth in the optical transmission field was achieved. Also, with the development of a wavelength division multiplexed system which can transmit four through sixteen channels at the same time as well as a single channel, came the development of a wavelength division multiplexed fiber amplifier (WDM-EDFA).
In general, in the WDM-EDFA, amplification gain must be uniformly maintained at each wavelength since more than four channels must be uniformly amplified at the same time, unlike the case of a single channel, the current of a pump laser diode must be controlled so that there is little change in the amplification gain according to changes in the number of channels (add/drop).
In a conventional optical amplifier control system, the amplification gain is controlled by optical filtering each wavelength or reading channel information sent from the supervising channel to a switching station or a relay station. However, the system structure becomes complicated in order to filter on each wavelength. Accordingly, costs inevitably increase and the volume of the WDM-EDFA increases. Also, there is a technical problem in that filtering should be correctly performed for an interchannel space of 0.8 nm.
To solve the above problem, the supervising channel multiplexed data channels are extracted at the same time by an optical divider. The supervising channel is optically filtered from the extracted 10% of the signal and then examined. However, in such a case, 10% signal loss occurs and it becomes very difficult to input information on the state of the WDM-EDFA to the supervising channel. Namely, synchronization between the WDM-EDFA and a switching system, a multiplexer (MUX), and a demultiplexer (DEMUX) becomes necessary.
SUMMARY OF THE INVENTION
To solve the above problem(s), it is an objective of the present invention to provide a wavelength division multiplexed optical amplifier control system by which it is possible to transfer the state of an optical amplifier to a switching station or a relaying station through a supervising channel and to control the amplification gain of each optical amplifier.
It is another objective of the present invention to provide a system of controlling a wavelength division multiplexed optical amplifier by which it is possible to perform remote supervision and remote control through a shorter path by linking adjacent optical amplifiers and a method control.
To achieve the first objective, there is provided a wavelength division multiplexed optical amplifier controlling system, comprising an optical exchange system for generating and interpreting a supervision channel optical signal, multiplexing the supervision channel and data channels comprised of a plurality of optical signals having different wavelengths, and transmitting and receiving the multiplexed channels and a plurality of optical amplifying portions located on a transmission path connected to the optical exchange system, for performing amplification so as to have even gain with respect to predetermined wavelength range which the data channel optical signal have according to the supervision channel optical signal information, and inserting the state information thereof into the supervision channel when the optical exchange system requests the state information thereof.
To achieve the second objective, there is provided a method for controlling and supervising the optical amplifying portion in the optical exchange system in an optical communication system in which the optical exchange system and the optical amplifying portion are connected to the optical transmission path, using a supervision channel, comprising the steps of (a) multiplexing the supervision channel optical signal having a predetermined form and a data channel optical signal comprised of optical signals having different wavelengths in the optical exchange system and transmitting the multiplexed optical signals, (b) separating the supervision channel from the optical signals multiplexed in the step (a) at the optical amplifier and amplifying the data channel optical signal according to predetermined control information included in the separated supervision channel, (c) converting the state information of the optical amplifying portion into an optical signal, loading the converted optical signal into the supervision channel, combining the supervision channel with the data channel amplified in the step (b), and transmitting the combination result, and (d) demultiplexing the optical signal at the optical exchange system, and checking the state of the optical amplifying portion by interpreting the supervision channel optical signal in the demultiplexed signal.
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Leydig , Voit & Mayer, Ltd.
Moskowitz Nelson
Samsung Electronics Co,. Ltd.
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