Wavelength division multiplexing (WDM) remains the prevailing technology for adding flexibility and functionality to today’s optical networks. By transmitting signals at different wavelengths through the same fiber, WDMs can multiply transmission capacity, improve testing, and transmit voice services over video. Value-Added Module (VAM) systems equipped with WDM technology are used in a variety of applications to reduce operational expenses and increase revenue opportunities. | WDM Module Value-Added Module VAM System Overview Wavelength division multiplexing WDM remains the prevailing technology for adding flexibility and functionality to today s optical networks. By transmitting signals at different wavelengths through the same fiber WDMs can multiply transmission capacity improve testing and transmit voice services over video. Value-Added Module VAM systems equipped with WDM technology are used in a variety of applications to reduce operational expenses and increase revenue opportunities. application note Increasing Transmission Capacity Fiber overlays can be expensive and time consuming. In order to deliver broadband services many service providers are integrating WDM modules into the network to gain capacity without deploying additional fiber. Adding a WDM on each end of a circuit instantly doubles the bandwidth on a fiber pair. A typical application features one fiber for the transmit direction and another fiber for the receive direction. See Figure 1. In most cases legacy equipment will operate at 1310 nm. It is simply a matter of incorporating a WDM module at each end of the span and adding new equipment transmitting at 1550 nm. In a higher capacity network transmission signals operating at 1310 nm and 1550 nm are then simultaneously transmitted over the same fibers. See Figure 2. This enables the existing fiber in the plant to double capacity. The WDM approach also enables providers to work with existing electronic equipment which proves to be much more cost-effective than incorporating new DWDM modules or additional fibers into the network. 1310 FOT 1310 FOT Tx Rx - i Near End 1310 1310 Single Fiber Figure 1 Original Network Tx Rx Far End Uifll Value-Added Module VAM System WDM Module WDM Module CN CO LT CO CN CN Near End Far End Figure 2 Higher Capacity Network with WDMs Nonintrusive Testing WDM modules introduce out-of-band testing by enabling networks to operate and test at different wavelengths. A network operating at 1310 .
