What is Mode Conditioning Patch Cable

Mode conditioning patch cable, also known as conditioned launch fiber cables, are used specifically in Gigabit Ethernet 1000BASE-LX (and 1000Base-LH) applications where the objective is deploying new high-speed 1000BASE-LX routers, switches, or transceivers within existing multimode system backbones.

Optical Mode Conditioners provide a convenient and reliable method of connecting multimode fiber plants with

1000Base- LX based transmission equipment compliant with IEEE 802.3 standards. Mode conditioners provide a method of offsetting a single-mode fiber core with a corresponding multimode fiber. This calibrated offset reduces a phenomena called differential mode dispersion, or DMD, which can cause the transmitting laser pulse to spread out and merge into neighboring pulses creating bit errors in the transmission signal.

Mode conditioners are built in the form of a simple duplex patch cable, so they can easily be installed in a system without the need for additional components or hardware. Their length can range from one meter and up to support virtually any network topography.

The reason we need to use the mode conditioning patch cord :

the Gigabit Ethernet application standard requires the use of fiber optic light to achieve the specified data transmitting rates. Usually people use long wave transceiver modules for Gigabit Ethernet, these modules have to operate both single mode and multi mode fibers. And as we know, multimode fiber manufacturing techniques create index of refraction anomalies along the centerline of the multi mode fiber core. When a highly concentrated single mode fiber optic light is sent into the center of a multimode fiberglass, the modes that propagate through the index of refraction anomalies spread out in time causing modal dispersion, this effect is called differential mode delay. Differential mode delay results in reduced bandwidth over distance. By allowing the single mode laser launch to be offset away from the center of the multi mode fiber the mode conditioning patch cord reduces the effect of such differential mode delay.

Using tips mode conditioning cables to patch an existing multimode cable plant to your Gigabit LX equipment.

1.Usually used in pairs, mode conditioning cables usually require a MC cable at each end to connect the equipment to the cable plant. The only reason to order an odd number of mode conditioning cables is to have a spare on hand.

2. If your Gigabit LX switch is equipped with SC or LC connectors, please be sure to connect the yellow leg (singlemode) 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 be maintained on both ends. The swap of transmit and receive can only be done at the cable plant side.

how to use such mode conditioning cables

when we use such mode conditioning fiber optic patch cords, we need to connect the yellow leg which is the color of single mode to connect the transmit side of the equipment (single mode Gigabit transceiver) while we connect the orange leg which is the color of multimode to the receive side. (Multimode Gigabit cable plant)