Multi-wavelength/multi-channel system
First Claim
1. An optical transmission WDM-system comprising a transmitting side and a receiving side and an optical fiber link connecting the transmitting and receiving sides, high-priority information being transmitted in the optical fiber link from the transmitting side to the receiving side in a plurality of wavelength bands, the wavelength bands having different transmission characteristics and transmission characteristics varying with time, in particular different polarization mode dispersions and/or polarization mode dispersions varying with time, the WDM-system further comprising a switch for transmitting the high-priority information in a number of the wavelength bands which is smaller than the total number of wavelength bands and a controller connected to the switch for at each instant selecting the wavelength bands used for transmitting the high-priority information to give a sufficient total quality of the transmission of the high-priority information.
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Abstract
In a fiber-optical WDM-transmission system channel switching is used to achieve a high transmission capability and/or quality in spite of the polarization mode dispersion experienced by pulses propagating along an optical fiber. The WDM-channels having best transmission properties among the available WDM-channels are used to transmit high-priority traffic, the remaining channels being used for e.g. low-priority traffic. The high- and low-priority information arrives on input lines and is switched in a cross-connect element coupling the high-priority information to the best channels and the other information to the other channels, the channels being combined in a multiplexer to be injected in the transmission fiber. The light propagating in the fiber is divided into the respective channels by a demultiplexer which are converted to electrical signals by receivers and provided to a cross-connect element switching the channels carrying the high-priority information to output lines and those carrying the low-priority information to other output lines. The receivers provide a measure of the transmission quality of the received channels to a control unit which sends signals to the cross-connect elements controlling the switching thereof.
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Citations
15 Claims
- 1. An optical transmission WDM-system comprising a transmitting side and a receiving side and an optical fiber link connecting the transmitting and receiving sides, high-priority information being transmitted in the optical fiber link from the transmitting side to the receiving side in a plurality of wavelength bands, the wavelength bands having different transmission characteristics and transmission characteristics varying with time, in particular different polarization mode dispersions and/or polarization mode dispersions varying with time, the WDM-system further comprising a switch for transmitting the high-priority information in a number of the wavelength bands which is smaller than the total number of wavelength bands and a controller connected to the switch for at each instant selecting the wavelength bands used for transmitting the high-priority information to give a sufficient total quality of the transmission of the high-priority information.
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9. A method of transmitting in a plurality of wavelength bands high-priority information over an optical fiber link connecting a transmitting side to a receiving side, comprising the steps of:
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transmitting light signals in the optical fiber link in the wavelength bands, the wavelength bands having different transmission characteristics and transmission characteristics varying with time, in particular different polarization mode dispersions and/or polarization mode dispersions varying with time, and selecting at each instant wavelength bands for transmitting the high-priority information, the number of the selected wavelength bands being smaller than the total number of wavelength bands, using only the selected wavelength bands for transmitting the high-priority information in the optical fiber link the selecting of the wavelength bands being made to give a sufficient total quality of the transmission of the high-priority information. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification