Fiber Optic Cabling
Voyager Matrix Fiber Optic Switch
Installation and User Guide
26
A.2
Fiber Optic Cable Terminology
When specifying and using fiber-optic cable and systems, often there is considerable confusion surrounding
various common terms relating to them.
Single-Mode vs. Multi-Mode
–
These terms refer to the
TYPE
of glass fiber. Specifically, how the glass fiber-
optic core is manufactured. Both types have an outer (buffer) diameter of approximately 125 microns, and an
outer protective jacket structure. For typical fiber-optic cables, multi-mode and single-mode fiber have the
following general features:
Multi-mode fiber:
Fiber core diameter: 50 or 62.5 microns in diameter. Outer buffer diameter is typically 125 microns.
Fiber quality ratings: OM4 is currently the recommended best quality. Lower grades, OM3, OM2 and
even OM1, can still function with Voyager, though with reduced extension capability.
Extension distance is more a function of fiber quality rating, not fiber loss (dB loss per meter). Signal
quality degrades (signal distortion increases) more quickly than the rate at which light is attenuated.
Patch cords and other fiber-to-fiber coupling methods will certainly introduce some additional signal
distortion and losses which must be accounted for.
Typical extension range for Voyager, using a single length of high quality OM4 cable is 2km.
Multi-mode fiber optic transceivers are generally much less expensive than single-mode optics.
Single-mode fiber:
Fiber core diameter: 9 microns in diameter. Outer buffer diameter is typically 125 microns.
Fiber quality ratings: OS1 is currently the recommended best quality. Lower grades, such as ungraded
single-mode fiber, can likely still function with Voyager, though with reduced extension capability.
Extension distance is more a function of fiber dB loss rating not fiber quality. Signal integrity is
maintained fairly well with SM fiber
– but the dB loss in optical power is the primary limit for extension
distance.
Patch cords and other fiber-to-fiber coupling methods will certainly introduce additional dB signal losses
which must be accounted for.
Typical extension range for Voyager, using a single length of high quality OS2 cable is 4km (with short-
range SM4K optics) or 30km (with long-range SM30K optics)
Single-mode fiber optic transceivers are generally much more expensive than multi-mode optics.
It can be difficult to determine visually whether the fiber-core is the single- or multi-mode type. Primarily, the most
reliable means of checking the type is to refer to the jacket color, LC-connector color, and printing on the outer
jacket of the fiber-optic cable. It should a
lways identify the manufacturer’s name and series or model number of
the cable material.