Understanding Fiber-Optic Cable Signal Loss, Attenuation, And Dispersion; Signal Loss In Multimode And Single-Mode Fiber-Optic Cable - Juniper MX960 Hardware Manual

Table 68: Supported SONET Standards (continued)
Standard
SONET/SDH OC48/STM16
Long Reach (LR-2)
SONET/SDH OC48/STM16
Short Reach (SR-1)
SONET OC192/STM64 Specifications
SONET/SDH OC192/STM64
Intermediate Reach (IR-2)
SONET/SDH OC192/STM64
Short Reach (SR-1)
SONET/SDH OC192/STM64
Long Reach (LR-2)
SONET OC768/STM256 Specifications
SONET/SDH OC768/STM256
Short Reach (SR)

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

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

Copyright © 2017, Juniper Networks, Inc.
Transceiver Specifications
SFP-1OC48-LR
SFP-1OC48-SR
XFP-10G-E-OC192-IR2
XFP-10G-L-OC192-SR1
XFP-10G-Z-OC192-LR2
PD-1OC768-SON-SR
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
Signal Loss in Multimode and Single-Mode Fiber-Optic Cable on page 139
Attenuation and Dispersion in Fiber-Optic Cable on page 140
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
single-mode fiber. Compared with multimode fiber, single-mode fiber has higher
bandwidth and can carry signals for longer distances.
Chapter 10: Transceiver and Cable Specifications
140.
139