28e fiber has recently become available. 3 SMF-28e fiber supports low water peak per- formance across the entire operating wavelength range, including a speci- fied attenuation at 1,383 nm of less than or equal to 0.31 dB/km with a hydrogen-induced attenuation increase of less than or equal to 0.01 dB/km. This fiber belongs to the family of extended wavelength band (EWB) fibers, as shown in Figure 2-94 (see also Table 2-1). SMF-28e fiber is an ITU G.652.C fiber and is compliant with all applicable industry standards. The additional operating wavelength potential opened by low attenuation in the water peak region combined with the emergence of systems designed to operate over those wavelengths translates into more options for network designers. They may choose to transmit more channels on a single fiber to Extended Wavelength Band SM Fiber Figure 2-9 EWB single-mode Supports E-Band, greater useable spectrum fiber. EWB Fiber eliminates the 1385 nm water peak Conventional Fiber Loss Conventional Fiber Spectrum EWB Fiber Spectrum EWB Fiber Loss Wavelength (nm) dB/km Example: EWB Fiber: 16 Wavelength CWDM Conventional SMF: 12 Wavelength CWDM Chapter 2 Table 2-1 Standard Single-Mode Fiber EWB Single-Mode Fiber Standards for Basic Fiber Types IEC (category) 6073-2-50 (EWB) G.652.B G.652.C (EWB) TIA 492CAAB (Class) (dispersion unshifted with low water peak) increase channel spacing to facilitate coarse wavelength division multi- plexing (CWDM) or reserve additional wavelengths for future use. 2.1.1 Signal Degradation The fiber medium degrades signal quality, as is the case in a copper medium or any other medium, although degradation is much less than that of copper. This greatly reduced attenuation is the reason why optical fiber can carry a signal over a longer distance or at a much higher bandwidth than copper. Two general kinds of degradation are shown in Figure 2-10: Attenuation of a signal or waveform Distortion of its shape Attenuation is a well-understood phenomenon. It is the loss of light energy as it travels al