sic DWDM transmission OC-48/OC-192 Lambda 2 OC-48/OC-192 MC VA MC VA Multiplexer arrangement. Multiplexer OC-48/OC-192 Lambda 3 OC-48/OC-192 MC VA MC VA Multiplexer Multiplexer OC-48/OC-192 OC-48/OC-192 MC VA MC VA Multiplexer Multiplexer In-Line Amp OC-48/OC-192 Lambda n OC-48/OC-192 MC VA MC VA Multiplexer Multiplexer MC VA = Microprocessor-Controlled Variable Attenuator Fiber Circuits at Location C Fiber Circuits at Location A Figure 5-14 Basic DWDM block diagram. Network Management Add/Drop Multiplexer Amplifier Amplifier W-E-E-W Terminal Terminal Fiber Circuits Dropped and Added to Location B Dense Wavelength Division Multiplexing (DWDM) Systems devices and dispersion compensation) and design enhancements to over- come the fiber nonlinearities that cause signal distortion in transmission. DWDM wavelengths fall within two bands: a blue band between 1,527.5 and 1,542.5 nm and a red band between 1,547.5 and 1,561 nm. Each band is dedicated to a particular direction of transmission. See Figure 5-15 for a view of the channel transmission characteristics of single-mode fiber cable. Looking at Table 5-3, we can see the distances on different types of fiber that EDFA enables. EDFA also enables the following: Amplification in the optical domain (no optical-to-electrical-to-optical [O-E-O] conversion required) Figure 5-15 (dB/km) Transmission characteristics of common fiber. Optical Fiber Loss Rayleigh Infrared Scattering Absorption Wavelength um Rayleigh scattering: 0.15 to 2.3 dB/kb in 0.85 um to 1.55 um region OH ion absorption: 0.01 to 5 dB/km (silica impurity) Infrared absorption: Sharply increases beyond 1.60 um region Waveguide imperfections: up to 0.1 dB/km (other scattering problems: Brillouin scattering and Raman scattering) Table 5-3 Fiber Type OC-48 Applications OC-192 and Hybrid OC-48/192 Applications Supportable Distances Amplifier 700 km 320 km to Amplifier NZDSF 700 km 450 km 700 km 400 km Chapter 5 Amplification of multiple signals simultaneously Format independence (analog, digital, pulse, and SO on)