Understanding Fiber-Optic Cable Signal Loss, Attenuation, And Dispersion In An Acx5000 Router; Signal Loss In Multimode And Single-Mode Fiber-Optic Cables - Juniper ACX5048 Manual

ACX5048 and ACX5096 Universal Access Router
Understanding Fiber-Optic Cable Signal Loss, Attenuation, and Dispersion in an
ACX5000 Router

Signal Loss in Multimode and Single-Mode Fiber-Optic Cables

94
WARNING: To comply with GR-1089 requirements, all intra-building copper
cabling used for SFP+ and QSFP+ ports must be shielded and grounded at
both ends.
CAUTION: Before router installation begins, a licensed electrician must attach
a cable lug to the grounding cables that you supply. See
Ground to an ACX5000 Router" on page
attached lug can damage the router.
Before connecting the router to earth ground, review the following information:
A protective earthing terminal bracket is provided in the accessory kit for connecting
the router to earth ground. This L-shaped bracket attaches to a post on the ACX5000
router left front mounting bracket, providing a protective earthing terminal for the
router. The grounding points are studs sized for M4 hex nuts. The grounding points are
spaced at 0.625 in. (15.86 mm). M4 hex nuts with integrated washers are provided in
the accessory kit.
The grounding lug required is a Panduit LCD10-10A-L or equivalent. This grounding lug
is provided in the accessory kit. The grounding lug provided accommodates 14–10 AWG
(2–5.3 mm²) stranded wire.
The grounding cable that you provide for a ACX5000 router must be 14 AWG (2 mm²),
minimum 60° C wire, or as permitted by the local code.
To determine the power budget and power margin needed for fiber-optic connections,
you need to understand how signal loss, attenuation, and dispersion affect transmission.
The ACX5000 routers uses various types of network cable, including multimode and
single-mode fiber-optic cables.
Signal Loss in Multimode and Single-Mode Fiber-Optic Cables on page 94
Attenuation and Dispersion in Fiber-Optic Cable on page 95
Multimode fiber is large enough in diameter to allow rays of light to reflect internally
(bounce off the walls of the fiber). Interfaces with multimode optics typically use LEDs
as light sources. However, LEDs are not coherent light sources. They spray varying
wavelengths of light into the multimode fiber, which reflects the light at different angles.
Light rays travel in jagged lines through a multimode fiber, causing signal dispersion.
When light traveling in the fiber core radiates into the fiber cladding (layers of lower
refractive index material in close contact with a core material of higher refractive index),
higher-order mode loss occurs. Together, these factors reduce the transmission distance
of multimode fiber compared to that of single-mode fiber.
"Connecting Earth
112. A cable with an incorrectly
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