Juniper QFX5200 User Manual

Table 33: QSFP+ MPO Fiber-Opc Crossover Cable Pinouts (Connued)
Pin Pin
10 3
11 2
12 1
Understanding QFX Series Fiber-Opc Cable Signal Loss, Aenuaon,
and Dispersion
IN THIS SECTION
Signal Loss in Mulmode and Single-Mode Fiber-Opc Cables | 79
Aenuaon and Dispersion in Fiber-Opc Cable | 80
To determine the power budget and power margin needed for ber-opc connecons, you need to
understand how signal loss, aenuaon, and dispersion aect transmission. The QFX Series uses various
types of network cables, including mulmode and single-mode ber-opc cables.
Signal Loss in Mulmode and Single-Mode Fiber-Opc Cables
Mulmode ber is large enough in diameter to allow rays of light to reect internally (bounce o the
walls of the ber). Interfaces with mulmode opcs typically use LEDs as light sources. However, LEDs
are not coherent light sources. They spray varying wavelengths of light into the mulmode ber, which
reect the light at dierent angles. Light rays travel in jagged lines through a mulmode ber, causing
signal dispersion. When light traveling in the ber core radiates into the ber cladding (layers of lower
refracve index material in close contact with a core material of higher refracve index), higher-order
mode loss occurs. Together, these factors reduce the transmission distance of mulmode ber compared
to that of single-mode ber.
79

Juniper QFX5200 Specifications

General

Brand	Juniper
Model	QFX5200
Category	Switch
Language	English