Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
1998-04-28
2001-07-03
Negash, Knife-Michael (Department: 2633)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S199200, C359S199200
Reexamination Certificate
active
06256125
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a WDM optical transmission system, and more particularly to, a WDM optical transmission system provided with means for monitoring and controlling wavelength components at each node.
BACKGROUND OF THE INVENTION
In wavelength division multiplexing (hereinafter also referred to as ‘WDM’) optical transmission systems, various network systems, e.g., a point-to-point system, an optical cross connect system and an optical ADM ring system, are constructed. Using already-installed transmission lines and equipment and the economization of the networks into account, optical transmission systems of this type need to transmit optical signals with various bit rates, e.g., 600 Mb/s, 2.4 Gb/s, 10 G/s while wavelength-multiplexing them using the already-installed transmission lines and equipment.
In this case, each node conducts linear-repeating to the next-stage node regardless of the bit-rate difference. However, it is known that the maximum transmission repeating distance (linear repeating distance) is limited due to a loss, a dispersion etc. in transmission line and depends upon the bit rate.
Because of this, the conventional WDM optical transmission systems have been designed considering previously the bit rates and repeat numbers of wavelength components to be received by the respective nodes.
However, the transmission system that the bit rate and repeat number are previously designed and fixed may not be flexibly applicable to the change of bit rate etc. to be required by an increase in transmission capacity. Then, the cost performance, reliability etc. of the network must be reduced that much.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a WDM optical transmission system in which the repeating transmission of all wavelength components can be performed regardless of the repeat number and bit rate.
According to the invention, a wavelength division multiplexing optical transmission system, comprises:
a wavelength-demultiplexing means for receiving a wavelength-multiplexed signal that a monitor-signal wavelength component is multiplexed to a plurality of main-signal wavelength components and demultiplexing the wavelength-multiplexed signal into wavelength components;
an optical switch for receiving the main-signal wavelength components demultiplexed by the wavelength-demultiplexing means and switching into either one of routes to output directly and to output through a bit-rate-selective type regenerator for each of the main-signal wavelength components;
the bit-rate-selective type regenerator for conducting the regenerative repeating to a signal input through the optical switch according to the bit rate and then returning it to the optical switch;
a monitor signal receiver for receiving and terminating the monitor-signal wavelength component demultiplexed by the wavelength-demultiplexing means;
a controller for detecting the bit rate and pass-through node number of each of the main-signal wavelength components by receiving a signal from the monitor signal receiver, generating a control signal to control the switching the optical switch and the regenerative repeating of the bit-rate-selective type regenerator, and rewriting information to show the bit rate, pass-through node number and execution
on-execution of regenerative repeating of each of the main-signal wavelength components to be output to the next-stage node;
a monitor signal transmitter for receiving the information rewritten by the controller and generating a monitor-signal wavelength component; and
a wavelength-multiplexing means for multiplexing the main-signal wavelength components output from the optical switch and the monitor-signal wavelength components output from the monitor signal transmitter.
According to another aspect of the invention, a point-to-point type wavelength division multiplexing optical transmission system, comprises:
a wavelength-demultiplexing means for receiving a wavelength-multiplexed signal that a monitor-signal wavelength component is multiplexed to the a plurality of main-signal wavelength components an demultiplexing the wavelength-multiplexed signal into wavelength components;
an optical switch for switching a wavelength component to need the regenerative repeating of the main-signal wavelength components demultiplexed by the wavelength-demultiplexing means into the side of a bit-rate-selective type regenerator as well as conducting the insertion of a signal from the bit-rate-selective type regenerator;
the bit-rate-selective type regenerator for conducting the regenerative repeating to a signal form the optical switch according to the bit rate;
a monitor signal receiver for receiving and terminating the monitor-signal wavelength component demultiplexed by the wavelength-demultiplexing means;
a controller for detecting the bit rate and pass-through node number of each of the main-signal wavelength components by receiving a signal from the monitor signal receiver, generating a control signal to control the switching of the optical switch into the side of the bit-rate-selective type regenerator for the wavelength component signal from the wavelength-demultiplexing means to need the regenerative repeating, and rewriting information to show the bit rate, pass-through node number and execution
on-execution of regenerative repeating of each of the main-signal wavelength components to the output of the next-stage node;
a monitor signal transmitter for generating a monitor-signal wavelength component according to a signal form the controller; and
a wavelength-multiplexing means for multiplexing the main-signal wavelength components output from the optical switch and the monitor-signal wavelength component output from the monitor signal transmitter.
According to another aspect of the invention, an optical cross connect type wavelength division multiplexing optical transmission system, comprises:
a wavelength-demultiplexing means for receiving a wavelength-multiplexed signal that a monitor-signal wavelength component is multiplexed to a plurality of main-signal wavelength components from several nodes and demultiplexing the wavelength-multiplexed signal into wavelength components;
an optical switch for outputting the main-signal wavelength components from the wavelength-demultiplexing means to an arbitrary node;
a bit-rate-selective type regenerator for conducting the regenerative repeating to a signal from the optical switch according to the bit-rate;
a monitor signal receiver for receiving and terminating the monitor-signal wavelength component demultiplexed by the wavelength-demultiplexing means;
a controller for detecting the bit rate and pass-through node number of each of the main-signal wavelength components by receiving a signal from the monitor signal receiver, generating a control signal to control the switching the of the optical switch into the side of the bit-rate-selective type regenerator for the wavelength component signal from the wavelength-demultiplexing means to need the regenerative repeating, and rewriting information to show the bit rate, pass-through node number and execution
on-execution of regenerative repeating of each of the main-signal wavelength components to be output to the next-state node;
a monitor signal transmitter for generating a monitor-signal wavelength component according to a signal from the controller; and
a wavelength-multiplexing means for multiplexing the main-signal wavelength components output from the optical switch and the monitor-signal wavelength component output from the monitor signal transmitter.
According to another aspect of the invention, an optical insertion/separation ADM ring type wavelength division multiplexing optical transmission system, comprises:
a wavelength-demultiplexing means for receiving a wavelength-multiplexed signal that a monitor-signal wavelength component is multiplexed to a plurality of main-signal wavelength components and demultiplexing the wavelength-multiplexed signal into wavelength components;
an optical switch for switching a wavele
McGuireWoods LLP
NEC Corporation
Negash Knife-Michael
LandOfFree
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