What is Mode Conditioning Patch Cable and Why Need It?

Fiber Optic Mode Conditioning Patch Cable(MCP) is one duplex multimode fiber patch cord, which has one short length of single-mode fiber at the start of the transmission end.

Gigabit Ethernet (GbE) requires a laser light source instead of an LED source to power the network, due to the lasers faster rise and fall times, the pulses of light injected into the fiber are more tightly packed together thus greater bandwidth.

Without the use of a mode conditioning patch cord, multiple signals are generated when a single-mode laser launch into the center of a multimode fiber. Multiple signals can be generated that overlap each other and make it difficult for the receiver to interpret. This condition is known as Differential Modal Delay (DMD).

The mode conditioning patch cord matches a single-mode fiber core with the corresponding multimode fiber core. Utilizing a calibrated offsetting between the single-mode and multimode fiber, it eliminates the so-called DMD effect.

Fiber optic mode conditioning cable provides a convenient, reliable method of connecting 1000BASE-LX/LH, 10GBASE-LX4 and 10GBASE-LRM based Gigabit Ethernet Transceiver modules to cable plants deploying multimode fibers, fully compliant with IEEE 802.3 standards.

MCP is manufactured in a standard form of a duplex fiber patch cord. And a mode conditioning cable can be installed in a fiber link without the need for additional components or hardware.

Things you should know about the deployment of Mode Conditioning Patch Cables:

• MCP is required for 1000BASE-LX/LH, 10GBASE-LX4, and 10GBASE-LRM transceivers transmitting in the 1300-nm window. it should never be used in 1000BASE-SX and 10GBASE-SR links in the 850-nm window.
• MCP is specified for applications over FDDI-grade, OM1, and OM2 fiber types. It should never be used for applications over OM3, also known as “laser-optimized fiber”.
• Usually used in pairs, when using 1000BASE-LX/LH, 10GBASE-LX4 and 10GBASE-LRM transceivers with legacy 62.5-micron or 50-micron multimode fiber, you must install a mode conditioning patch cord between the transceiver and the multimode cable plant on both ends of the link.
• If your Gigabit LX switch is equipped with SC or LC connectors, please be sure to connect the yellow leg (single-mode) of the cable to the transmit side, and the orange leg (multimode) to the receive side of the equipment. It is imperative that this configuration is maintained on both ends. The swap of transmitting and receive can only be done at the cable plant side. See the diagram below.

Mode Conditioning Cable Installation:

The mode-conditioning patch cord is installed between the transceiver and the patch panel. To install the patch cord, follow these steps:

• Step 1 Plug the yellow leg (single-mode connector) of the patch cable into the transmit port of the Gigabit Ethernet transceiver.
• Step 2 Plug the orange leg (multimode connector) of the patch cable into the receive port of the equipment.
• Step 3 At the other end of the patch cord, plug both multimode fiber connectors into the cable plant side.
• Step 4 Repeat Step 1 through Step 3 for the second transceiver located at the other end of the network link.