bining not only appropriate edge network element (NE) technology, but also waveguide technology-for example, Lucent True Wave RS fiber. True Wave RS works with off-the-shelf commercial lasers ensuring high laser yield, system interoperability, and multiple vendor sourcing-issues that ensure low-cost systems for service providers. Proponents make the case that CWDM solutions on AllWave are expected to yield an equipment cost sav- ings of 40 percent compared to DWDM over single-mode fiber. These sav- ings are achieved by using uncooled lasers and relaxing stringent DWDM filter specifications, and will result in an improvement in service provider gross profitability. Table 6-1 depicts key parameters for a typical CWDM system. The bottom line is that adding two to eight wavelengths per fiber in metro short-haul applications enables network designers to increase capac- ity without installing costly DWDM systems. CWDM represents significant costs savings-from 25 to 50 percent at the component level over DWDM, for original equipment manufacturers (OEMs) and service providers. At the time of this writing, CWDM prod- ucts cost about $3,500 per wavelength. That is half the price of regular DWDM products, which typically sell for $7,500 per wavelength. Tradi- tional CWDM only scales to about eight wavelengths, but for metro access applications, this may be adequate. Also, vendors have found ways to combine CWDM with regular DWDM blades that enable the system to scale up to 20 wavelengths. CWDM system architecture can benefit the Chapter 6 Table 6-1 CWDM Series Key Parameters for a Typical CWDM Center wavelength 1c 1,471.0, 1,491.0, 1,511.0, 1,531.0, System 1,551.0, 1,571.0, 1,591.0, 1,611.0 Passband bandwidth 1c +/- 6.5 Insertion loss In-band ripple Polarization dependent loss (PDL) Adjacent band isolation Return loss without connectors Directivity Operating power Operating temperature Storage temperature -40-85 Fiber type Corning SMF-28 Fiber package 900um loose tube metro access market because it takes advantage of the in