How Much Do You Know About Multi-mode Patch Cord?

Optical fiber is now an effective high-capacity data communication medium for it can support long distance transmission. It is a fiber constructed of glass or plastic, which does not contain any metal material and thus avoids Electro-Magnetic Interference (EMI) and distortion of information along with the distance. This results in high accuracy of data along the transmission cable. The data is modulated within the light waves. There are mainly two modes of cables available: single-mode and multi-mode. Multi-mode patch cord is multi-mode fiber cable terminated at both ends with fiber optic connectors. In this article, detailed information about multi-mode patch cords will be given to help you get a better understanding of them.

What Is Multi-mode Patch Cord?

Multi-mode patch cord is usually 50/125 and 62.5/125 microns in construction (shown in the following figure). The numbers 50 μm and 62.5 μm refer to the diameters of the glass or plastic core, the part of the fiber that carries the light which encodes your data. The number 125μm is the diameter of the cladding, which confines the light to the core because it has a lower index of refraction. The transition between the core and cladding can be sharp, which is called a step-index profile, or a gradual transition. The two types have different dispersion characteristics and thus different effective propagation distance. Multi-mode fiber cables may be constructed with either graded or step-index profile, and those with graded index fiber is better in accuracy and performance.

Multi-mode patch cord has a larger core diameter than single mode patch cable, allowing multiple modes of light to propagate. Due to this, the number of light reflections created as the light passes through the core increases, creating the ability for more data to pass through at a given time. Multi-mode patch cord has high dispersion and attenuation rate, which means the quality of the signal is reduced over long distances. Multi-mode patch cord is typically used for short distance transmission, for usually a distance less than 500 meters, such as data and audio/video applications in local area networks (LANs).

Types of Multi-mode Patch Cord

Multi-mode fiber optic cable is described using a system of classification determined by the ISO 11801 standard—OM1, OM2, and OM3—based on the modal bandwidth of multi-mode optical fiber. OM4, defined in TIA-492-AAAD by the TIA, was finalized in 2009. "OM" stands for optical multi-mode. Technically, OM1/OM2/OM3/OM4 multi-mode fiber did not define a specific fiber size, but rather their optical channel performance.

OM1 specifies 62.5μm fiber core size and OM2 specifies 50μm fiber core size. They are commonly used in premises applications supporting Ethernet rates of 10 Mbps to 1 Gbps, not suitable enough for today's higher-speed networks. They were ideal for use with LED transmitters. OM3 and OM4 specify an 850nm laser-optimized 50μm cable. They are both laser-optimized multi-mode fiber (LOMMF) and were developed to accommodate faster networks such as 10 Gbps, 40 Gbps, and even 100 Gbps. OM1/OM2/OM3/OM4 can sometimes be distinguished by jacket color: orange jackets for 62.5/125μm OM1 fiber and 50/125μm OM2 fiber, and aqua is recommended for 50/125μm "laser-optimized" OM3 and OM4 fiber.

Comparison Between OM3 and OM4

Both OM3 and OM4 are laser-optimized high bandwidth 50µm multi-mode fiber. The requirements of the OM4 standard are identical to OM3 with the sole exception of the bandwidth values. Both 850nm EMB and 850nm over-filled launch (OFL) bandwidth have been increased from the OM3 requirements. OM3 with a effective modal bandwidth of 2000 MHz·km and OM4 with an effective modal bandwidth of 4700 MHz·km. Laser optimized 50µm multi-mode fiber is the recommended fiber type in today's LAN and data center environments in conjunction with 850nm vertical-cavity surface-emitting lasers (VCSELs). For prevailing 10Gb transmission speeds, OM3 is generally suitable for distances up to 300 meters, and OM4 is suitable for distances up to 550 meters. With the spread of 40 and 100 Gigabit Ethernet, OM3 and OM4 also are only well positioned to support these burgeoning data rates over distances of 100m and 150m respectively. OM4 supports the majority of data center links that utilize 40 and 100 GbE in high-speed/high-performance computing applications driven by server virtualization, cloud computing, streaming video, and ever increasing IP traffic and convergence.

Conclusion

Multi-mode patch cord is a commonly used fiber optic jumper type for short distance transmission. And there are mainly four different kinds of multi-mode patch cord, OM1 multi-mode patch cord, OM2 multi-mode patch cord, OM3 multi-mode patch cord, and OM4 multi-mode patch cord. These four kinds of multi-mode patch cords have their own special applications. You can choose from according to your own needs.

Introduction to Mode Conditioning Patch Cable

Mode conditioning patch cord (MCP) was developed as a solution for network applications where Gigabit Ethernet hubs with laser based transmitters are deployed. It is a special fiber optic patch cord and allows customer upgrading their hardware technology without the cost of upgrading fiber plant. In addition, MCP significantly improves data signal quality while increasing the transmission distance. The text will give some detailed information about mode conditioning patch cable.

What Is Mode Conditioning Patch Cable?

A mode conditioning patch cord is a duplex multi-mode patch cord that has a small length of single mode fiber at the start of the transmission leg, and also a single mode to multi-mode offset fiber connection part in this leg. There are two multi-mode fibers on one end and one multi-mode and one single mode fiber on the other end. It is fully compliant with IEEE 802.3z application standards. Mode conditioning patch cord causes the single mode transceiver to create a launch similar to a typical multi-mode launch. It is designed for long wavelength Gigabit Ethernet applications. The following picture shows the construction of a mode conditioning patch cable.

How Does Mode Conditioning Patch Cable Work?

The basic principle behind the cord is that you launch your laser into the small section of single mode fiber. The launch of the light coming out of the equipment begins on a single mode fiber. The other end of the single mode fiber is coupled to multi-mode section of the cable with the core offset from the center of the multi-mode fiber. The light is launched on to the multi-mode fiber at a precise angle, giving the cable its mode conditioning properties. 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 multi-mode to the receive side. The picture below shows how the single mode fiber is coupled to multi-mode section of the cable.

How to Install Mode Conditioning Patch Cable?

To install a mode conditioning patch cable, you need to follow these steps:

• Step1: Connect the yellow leg (single mode connector) of the MCP cable into the transmit bore of the transceiver.
• Step2: Connect the rest orange legs (multi-mode connectors) of the MCP cable into the receive bore of the transceiver.
• Step3: At the other end of the patch cord, put all the orange legs (multi-mode connectors) into the patch panel.
• Step4: Repeat the above three steps for the second transceiver located at the other end of the network link.

After you have finished all the connection steps above, all the swap of transmit and receiver can only be done at the cable plant side.

Why Do We Need Mode Conditioning Patch Cable?

Transceiver modules used in Gigabit Ethernet (1000 Base-LX) launch only single mode (1300nm) long wave signals, which poses a problem if an existing fiber network utilizes multi-mode cable. When a single mode signal is launched into a multi-mode fiber a phenomenon known as differential mode delay (DMD) can create multiple signals within the multi-mode fiber. This effect can confuse the receiver and produce errors. By allowing the single mode laser launch to be offset away from the center of the multi-mode fiber, mode conditioning patch cord reduces the effect of such differential mode delay and provides a much higher operational bandwidth by precisely aligning a single mode termination at the laser transmitter. This is essential for networks using 62.5/125 and 50/125 multi-mode optical fiber and may be specified for current multi-mode networks depending upon the system requirements.

Mode conditioning patch cables are with various options, from all types of connectors to different jackets and different lengths. A variety of fiber optic connectors are available for your convenience, including: LC/UPC, SC/UPC, FC/UPC, ST/UPC, LC/APC, SC/APC, FC/APC, and MTRJ. Mode conditioning patch cables 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.

Originally published at www.fiber-optic-cable-sale.com