Dispersion compensation method in optical communication system having optical add drop multiplexing capability

A method of setting the amount of dispersion compensation in a wavelength division multiplexing optical communication system, which includes a transmitting-end terminal node and a receiving-end terminal node;

• a wavelength division multiplexing optical communication transmission line including a plurality of spans each having an optical fiber, the plurality of spans joining the transmitting-end terminal node and the receiving-end terminal node;
• and a plurality of add drop multiplexing (OADM) nodes disposed on the wavelength division multiplexing optical communication transmission line;
• the method comprising the steps of:
• taking as the reference a residual dispersion target value of between the transmitting-end terminal node and the receiving-end terminal node;
• figuring out ratios of the span counts in a node segment between one of the terminal nodes and one of the add drop multiplexing (OADM) nodes and in a node-to-node segment between two of the add drop multiplexing (OADM) nodes, to the total span count between the transmitting-end and receiving-end terminal nodes;
• and
• setting residual dispersion target values for the node segment between one of the terminal nodes and one of the add drop multiplexing (OADM) nodes and a residual dispersion target value for the node-to-node segment between two of the add drop multiplexing (OADM) nodes, so as to be proportional to the ratios, using the residual dispersion target value obtained as the reference in the taking step.

A wavelength division multiplexing optical communication system comprising:

• a transmitting-end terminal node and a receiving-end terminal node;
• a wavelength division multiplexing optical communication transmission line including a plurality of spans each having an optical fiber, the plurality of spans joining the transmitting-end terminal node and the receiving-end terminal node;
• and
• a plurality of add drop multiplexing (OADM) nodes disposed on the wavelength division multiplexing optical communication transmission line;
• wherein
• when taking as the reference a residual dispersion target value of between the transmitting-end terminal node and the receiving-end terminal node, a residual dispersion target value for a node segment between one of the terminal nodes and one of the add drop multiplexing (OADM) nodes and a residual dispersion target value for a node-to-node segment between two of the add drop multiplexing (OADM) nodes are set so as to be proportional to ratios of the dispersion in the node segment and in the node-to-node segment, respectively, to the total dispersion between the transmitting-end and receiving-end terminal nodes.

A wavelength division multiplexing optical communication system comprising:

• a transmitting-end terminal node and a receiving-end terminal node;
• a wavelength division multiplexing optical communication transmission line including a plurality of spans each having an optical fiber, the plurality of spans joining the transmitting-end terminal node and the receiving-end terminal node;
• and
• a plurality of add drop multiplexing (OADM) nodes disposed on the wavelength division multiplexing optical communication transmission line;
• wherein
• when taking as the reference a residual dispersion target value of between the transmitting-end terminal node and the receiving-end terminal node, a residual dispersion target value for a node segment between one of the terminal nodes and one of the add drop multiplexing (OADM) nodes and a residual dispersion target value for a node-to-node segment between two of the add drop multiplexing (OADM) nodes are set so as to be proportional to ratios of the length in the node segment and in the node-to-node segment, respectively, to the total length between the transmitting-end and receiving-end terminal nodes.