Cisco Systems NPE-225 Manual De Usuario

A mode-conditioning patch cord can be used with the WS-G5486= or GBIC-LX/LH= to allow reliable 
laser transmission between the single-mode laser source on the GBIC 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 

) to a graded-index 

multimode optical fiber. 

 shows a diagram of the mode-conditioning patch cord assembly.

2.

A mode-conditioning patch cord is required.

 

When using the WS-G5486 or GBIC-LX/LH with 62.5-micron diameter MMF, you must install a mode-conditioning patch 
cord between the GBIC and the MMF cable on both the transmit and the receive ends of the link when link distances are 
greater than 984 ft (300 m). We do not recommend using the WS-G5486 or GBIC-LX/LH and MMF with no patch cord for 
very short link distances (tens of meters). The result could be an elevated bit error rate (BER).

3.

Dispersion-shifted single-mode optical fiber cable.

 provides the GBIC transmit and receive power requirements and power budget.

WS-G5484 or 
GBIC-SX

–9.5 dBm

1

–4 dBm

–17 dBm

0 dBm

7.5 dBm

2

WS-G5486 or 
GBIC-LX/LH

–9.5 dBm

3

–11.5dBm

4

–3 dBm

5

–20 dBm

–3 dBm

7.5 dBm

6

 and 8.0 dBm

7

WS-G5487 or 
GBIC-ZX

0 dBm

5.2 dBm

–24 dBm

–3 dBm

–24 dBm

1.

For fiber types 50/125 

μ

m, NA = 0.20 fiber and 62.5/125 

μ

m, NA = 0.275 fiber.

2.

For fiber types 50 

μ

m MMF and 62.5 

μ

m MMF.

3.

For fiber types 9/125 

μ

m SMF.

4.

For fiber types 62.5/125 

μ

m MMF and 50/125 

μ

m MMF.

5.

For fiber types 9/125 

μ

m SMF, 62.5/125 

μ

m MMF, and 50/125 

μ

m MMF.

6.

For fiber types 50 

μ

m MMF and 62.5 

μ

m MMF.

7.

For fiber type 10 

μ

m SMF.