Single Mode & MultiMode Fiber
Our Industry and NMR
In the past NMR has primarily used Multimode fiber across departments; however, over the course of the last few months, Video has moved to single mode fiber.
For the most part, the industry standard has been single mode for larger production houses and broadcast companies. Even among our sub-rental partners, single mode is more available. Along with engineering reasons, we have chosen to standardize to single mode cable in the Video/LED departments.
Audio remains multimode, so differentiating between the two is paramount.
Distance and Capacity
Single mode has greater distance and bandwidth capability vs Multimode.
(In the graphic below, OM=MULTIMODE OS=SINGLE MODE)
Wavelength, Light Source, and Bandwidth
Multimode light sources for transmitters are LEDs (light-emitting diodes) and VCSELs (vertical cavity surface-emitting lasers) that work at the 850nm and 1300nm wavelength, and are available in 1G and 10G bandwidth capacities.
Single mode fiber often uses a laser or laser diodes to produce light injected into the cable. And the commonly used single mode fiber wavelength is 1310 nm and 1550 nm, also available in 1G and 10G. Our LED processing and some audio inventory requires 10G.
This is helpful to know when choosing SFP’s (Small Form-factor Pluggable) to be used to connect network switches via fiber. Our inventory consists of both Multimode (1G &10G) and Single mode (1G & 10G), and must be used as a matched pair along with the appropriate fiber type. The images below show examples of where to find the wavelength and bandwidth markings on SFP's.
Can I mix single mode and multimode fiber types and devices?
The answer for this question is “no.” Multimode fiber and single mode fiber have different core sizes, and the number of light modes that they transmit is also different. If you mix the two fibers, or connect them together directly, you’ll lose a large amount of optical loss, resulting in unreliability. Generally, never mix different types of cabling and devices randomly; it may work but will not be reliable.
Patch Cable Color Sheath
According to the TIA-598C standard definition, for non-military applications, single mode cable is coated with yellow outer sheath, and multimode fiber is coated with orange or aqua jacket.
Tactical Color Sheath Counting direction of a group of 2-12 fibers
TAC or Tactical fiber cable assembly is a fiber-optic cable that is designed for high strength, and to be used in harsh environments.
For cables that consist of multiple strands referred to as TAC-(Strand Count) or TAC-2, TAC-4 and TAC-12 each strand will be numbered or colored following the same fiber color code, e.g., 1st tube is blue, 2nd is orange, etc.
Fiber Cleaning
One aspect of fiber that often goes overlooked is maintenance. Cleaning and testing are at the core of maintaining properly working fiber. Below are two video fiber cleaning tools and processes. Work boxes typically contain fiber cleaning tools which should be used prior to connecting devices.
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