Extending the reach of WDM networks by combating high channel resolution power divergence using dynamic power equalization

Computer simulations are used to show that a combination of high channel resolution dynamic power equalization along with configurable amplifier gain flattening devices can be used to extend the reach of an optical network from 1700 km to well above 2500 km (a reach improvement of about 50%). This will extend the system or network into the ultra long-haul regime possibly enabling coast-to-coast connectivity. The relatively inexpensive configurable amplifier gain flattening devices can be used at every amplifier stage in the network to provide flat amplifier gain but their resolution is not enough to deal with single channel power variations. The addition of a few high channel resolution dynamic power equalizing devices at strategic points in the network allows combating effects like polarization dependent loss (PDL) induced ripple, shown to be important in networks , as well as dynamic channel add/drops.