Transceiver And Cable Specifications; Understanding Fiber-Optic Cable Signal Loss, Attenuation, And Dispersion; Signal Loss In Multimode And Single-Mode Fiber-Optic Cable - Juniper MX2020 Hardware Manual

CHAPTER 11

Transceiver and Cable Specifications

Understanding Fiber-Optic Cable Signal Loss, Attenuation, and Dispersion

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

Copyright © 2015, Juniper Networks, Inc.
Understanding Fiber-Optic Cable Signal Loss, Attenuation, and Dispersion on page 127
Calculating Power Budget and Power Margin for Fiber-Optic Cables on page 128
CB-RE Interface Cable and Wire Specifications for MX Series Routers on page 130
Installing an MX2020 Three-Phase Wye AC Power Cord on page 131
Network Cable and Transceiver Overview for ACX Series, M Series, and MX Series
Routers on page 134
Supported Network Interface Standards by Transceiver for ACX, M, MX, and T Series
Routers on page 135
This topic describes signal loss, attenuation, and dispersion in fiber-optic cable. For
information about calculating power budget and power margin for fiber-optic cable, see
"Calculating Power Budget and Power Margin for Fiber-Optic Cables" on page 128
"Supported Network Interface Standards by Transceiver for ACX, M, MX, and T Series
Routers" on page 135 or Supported Network Interface Standards by Transceiver for PTX
Series Routers.
Signal Loss in Multimode and Single-Mode Fiber-Optic Cable on page 127
Attenuation and Dispersion in Fiber-Optic Cable on page 128
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 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, higher-order mode loss results.
Together these factors limit the transmission distance of multimode fiber compared with
single-mode fiber.
Single-mode fiber is so small in diameter that rays of light can reflect internally through
one layer only. Interfaces with single-mode optics use lasers as light sources. Lasers
generate a single wavelength of light, which travels in a straight line through the
and
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