Cisco 7206VXR Configuration Guide - Page 119

Chapter 3 Installing a Cisco 7200 VXR Router Connecting I/O Controller, NPE-G1, or NPE-G2 Cables Table 3-4 provides NPE-G2 CWDM SFP module configuration information. Table 3-4 NPE-G2 CWDM SFP Module Configurations CWDM Product Number CWDM-SFP-1470 CWDM-SFP-1490 CWDM-SFP-1510 CWDM-SFP-1530 CWDM-SFP-1550 CWDM-SFP-1570 CWDM-SFP-1590 CWDM-SFP-1610 Color Gray Violet Blue Green Yellow Orange Red Brown Mode-Conditioning Patch Cord Description A mode-conditioning patch cord can be used with the SFP-GE-L= (SFP module) to allow reliable laser transmission between the single-mode laser source on the SFP module and a multimode optical fiber cable. When an unconditioned laser source designed for operation on single-mode optical fiber is directly coupled to a multimode optical fiber cable, an effect known as differential mode delay (DMD) might result in a degradation of the modal bandwidth of the optical fiber cable. This degradation results in a decrease in the link span (the distance between a transmitter and a receiver) that can be supported reliably. The effect of DMD can be overcome by conditioning the launch characteristics of a laser source. A practical means of performing this conditioning is to use a device called a mode-conditioning patch cord. A mode-conditioning patch cord is an optical fiber cable assembly that consists of a pair of optical fibers terminated with connector hardware. Specifically, the mode-conditioning patch cord is composed of a single-mode optical fiber permanently coupled off-center (see Offset in Figure 3-17) to a graded-index multimode optical fiber. Figure 3-17 shows a diagram of the mode-conditioning patch cord assembly. OL-5013-09 Cisco 7200 VXR Installation and Configuration Guide 3-23