Network Cable Specifications And Guidelines; Signal Loss In Multimode And Single-Mode Fiber-Optic Cable; Attenuation And Dispersion In Fiber-Optic Cable; Calculating Power Budget For Fiber-Optic Cable - Juniper SRX 5600 Hardware Manual

Appendix E

Cable and Wire Guidelines and
Specifications

Network Cable Specifications and Guidelines

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

To prepare for device or component installation, ensure that you have all required
cables and wires.
Network Cable Specifications and Guidelines on page 197
Routing Engine Interface Cable and Wire Specifications on page 200
The various IOCs supported on the services gateway accept different kinds of network
cable, including multimode and single-mode fiber-optic cable. For more information,
see the following sections:
Signal Loss in Multimode and Single-Mode Fiber-Optic Cable on page 197
Attenuation and Dispersion in Fiber-Optic Cable on page 198
Calculating Power Budget for Fiber-Optic Cable on page 198
Calculating Power Margin for Fiber-Optic Cable on page 199
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. LEDs are not coherent sources, however. 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 (HOL) results. Together these factors limit the transmission
distance of multimode fiber compared to 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. It is consequently more
expensive.
Network Cable Specifications and Guidelines
197