The multimode physical layer allows the operating distances outlined in Table 2. It is important that a multimode link consist
of only one fiber type; for example, all 50/125 micron fiber or all 62.5/125 micron multimode fiber.
Mixed fiber types in a multimode link are not supported. The 50/125 micron fiber is now available in
both standard (500 MHzvkm) and high bandwidth (2000 MHzvkm). Mixing the two is not supported.
Table 1. Multimode cable plant for OM2 limiting variants
FC-0
400-M5-SN-I
800-M5-SN-S
1600-M5-SN-S
3200-M5E-SN-I
Data rate (MB/s)
400
800
1600
3200
Operating range (m)
0.5 - 150
0.5 - 50
0.5 - 35
0.5 - 20
Loss Budget (dB)
2.06
1.68
1.63
1.57
Table 2. Multimode cable plant for OM3 limiting variants
FC-0
400-M5E-SN-I
800-M5E-SN-I
1600-M5E-SN-I
3200-M5E-SN-I
Data rate (MB/s)
400
800
1600
3200
Operating range (m)
0.5 - 380
0.5 - 150
0.5 – 100
0.5 - 70
Loss Budget (dB)
2.88
2.04
1.86
1.75
Table 3. Multimode cable plant for OM4 limiting variants
FC-0
400-M5F-SN-I
800-M5F-SN-I
1600-M5F-SN-I
3200-M5E-SN-I
Data rate (MB/s)
400
800
1600
3200
Operating range (m)
0.5 - 400
0.5 - 190
0.5 – 125
0.5 - 100
Loss Budget (dB)
2.95
2.19
1.95
1.86
Table 4. Multimode cable plant for OM5 limiting variants
FC-0
400-M5F-SN-I
800-M5F-SN-I
1600-M5F-SN-I
3200-M5E-SN-I
Data rate (MB/s)
400
800
1600
3200
Operating range (m)
0.5 - 400
0.5 - 190
0.5 – 125
0.5 - 100
Loss Budget (dB)
2.95
2.19
1.95
1.86
The use of LX multimode fiber links will require the appropriate mode conditioning patch cable or
equivalent installed on both ends of a duplex link (the mode conditioner must be plugged directly
into the optical transceiver on the adapter card, it cannot be inserted at a patch panel or
elsewhere in the middle of a link). The mode conditioning patch cable is a special fiber optic
jumper cable which contains both single mode (yellow jacket) and multimode (orange or aqua jacket)
optical fiber. A different mode conditioner is required for operation with 50/125-μm or
62.5/125-μm multimode trunk fiber cable. These cables, along with the appropriate duplex
adapters, are available from IBM®.
Note: In some fiber optic applications, it is possible to use a long
wavelength (1300 nm) single mode laser adapter with multimode fiber
by placing a special device known as an optical-mode conditioner
at both ends of the link. The optical mode conditioner resembles a
standard 2 meter jumper cable, and is sometimes known as a mode
conditioning patch (MCP) cable. Note that MCP is only supported
at 1.0625 Gbps. As shown in Figure 1, the MCP is unique
in that it contains both single mode (yellow) and multimode (orange
or aqua) fibers in a single jumper cable assembly. Without the MCP,
it is not possible to use a single mode laser transmitter over
multimode fiber because the laser source does not launch an equal
amount of optical power into all modes of the fiber; this leads to
excessive dispersion of the data pulses, and the link will not
function. The MCP is designed to “condition” the laser
launch so that the optical power fills all modes of the fiber equally
The MCP is installed on both ends of a link, and occupies the same space as a standard 2 meter
jumper cable. Adapter kits containing the MCPs and suitable duplex couplers for attachment to the
existing multimode cable infrastructure are available from IBM. Different MCPs are required for 50.0
micron or 62.5 micron multimode fiber.
