When Is It Best To Use Multimode Fiber Optic Cable?

Fiber optic cables are the medium of choice in telecommunications infrastructure, enabling the transmission of high-speed voice, video, and data traffic in enterprise and service provider networks. Generally speaking, there are two major kinds of fiber-optic cabling: single-mode and multi-mode.

While it's not impossible to get the two types to interact with the right transceivers and intermediate hardware, there's significant signal loss involved in the transition and, therefore, much higher power requirements to re-boost it. It's best to simply lay the kind of fiber that best meets your needs.

What Makes Multi-Mode Fiber Different

The significant difference in multi-mode is the size of its "core," the actual glass wire which holds/transmits optical signals. While single-mode uses a very thin core, which isolates the laser to a single beam, multi-mode allows it to reflect back and forth within the core. The following factors make multi-mode fiber superior to single-mode fiber in some certain aspects.

1. Specifically designed for use with “cheaper” light sources.

• The wide core lets you use incoherent LED light sources.
• Or cheaper, less precisely aimed lasers (such as VCSELs).
• And reduces tolerance requirements for alignment of connectors.

2. But this comes at the expense of long-distance reach.

• The wide core allows multiple modes of light to propagate.
• This causes “modal distortion”, which severely limits distance.
• Typically limited to 20-500 meters, depending on the signal type.

3. Augmented with “laser optimized” (OM3) MMF

• Uses aqua colored cables, rather than the traditional orange.
• Designed to achieve 10Gbps at 300 meters with VCSEL lasers. For example, both Finisar FTLX8571D3BCV and NETGEAR AXM761 SFP+ transceiver can reach distance of 300m over OM3 multi-mode fiber at the max data rate of 10 Gbps.    

Typical Uses For Multi-Mode Fiber

1 - A Fiber Backbone
Broadly, the most common application for multi-mode is to create a backbone for a company's network. If you're looking at 802.11ac or newer WiFi access points, a multi-mode fiber backbone is virtually required to get top speeds out of your access points.

2 - High Speed Local Deployments
Some businesses, especially those dealing in very large data sets, are starting to simply roll out multi-mode throughout their office. If your employees are regularly sending gigabyte-sized files around, this is currently one of the best options for boosting their transmission speeds.

3 - "Fiber To The Telecom Enclosure" (FTTE)
As a compromise between the two above options, some companies split it down the middle. The fiber connection continues past their server, and goes to a "Telecommunications Enclosure" (TE) which is in a central location, near to the employees connected to it.

It's an affordable way to deliver fiber, almost all the way to the desktop, without the higher expenses of a full wiring job. The main drawback is that your TE is nearly as vulnerable as your server room in terms of security, and would have to be tightly protected from intrusion.

Summary

When it is best to use multi-mode fiber optic cable is determined by many factors, like the distances, costs, associated transceivers, etc. It must be selected according to specific applications and needs. As one of the main fiber optical manufacturers in China, Fiberstore offer various types of fiber optic cables including single-mode, multimode as well as plenum cable, PVC/LSZ cable and so on to meet your specific applications and needs. With the higher bandwidths, flexibility, and security, all these fiber optic cables offer a promising solution to current networking challenges.

Reference:http://info.hummingbirdnetworks.com/blog/when-is-it-best-to-use-multimode-fiber-optic-cable

FAQ on Fiberstore 40G Cabling and Transceivers

With an increasing demand for more bandwidths, faster data rates and higher performance in telecommunication networks, the business case for 40 Gigabit Ethernet is becoming inescapably compelling. However, many users may feel confused when using 40G cables and optical transceivers. This article will solve the most frequently asked questions on Fiberstore’s 40G cabling and transceivers.

Q1: What 40G cables and transceivers are available from Fiberstore?
Fiberstore supplies a full range of both copper cables and optical transceivers for 40GbE, compliant to the IEEE standards. For copper both QSFP+ to QSFP+ (40G to 40G) and QSFP+ to SFP+ (40G to 4x10G) cables enable short reach options. For longer distances, Fiberstore offers a wide range of optical transceivers for various fiber types and reach requirements.

Q2: What does the IEEE 40GBASE-X standard describe?
The IEEE 40GBASE-X standard describes the following:

• 40GBASE-SR4
  It reaches 40-Gbps Ethernet over four short-range multimode fiber optic cables and supports link lengths of 100m and 150m respectively on laser-optimized OM3 and OM4 multimode fiber cables. In this process, the multimode fiber uses parallel-optics transmission instead of serial transmission due to the 850nm vertical-cavity surface-emitting laser (VCSEL) modulation limits. For example, Mellanox MC2210411-SR4 compatible 40GBASE-SR4 QSFP+ transceiver from Fiberstore supports link length of 100m over multimode fiber cable.
• 40GBASE-LR4
  It reaches 40-Gbps Ethernet over four wavelengths carried by a single long-distance singlemode fiber optic cable and supports link lengths of up to 10 km over single-mode fiber with duplex LC connectors. It operates at a wavelength of 1310 nm. The 40 Gigabit Ethernet signal is carried over four wavelengths with 10G on each wave.
• 40GBASE-CR4
  It is a direct attach cable segment with the QSFP+ modules attached to each end of the cable. It reaches 40-Gbps Ethernet over four short-range twinaxial copper cables bundled as a single cable and supports link lengths of up to 10 km over a standard pair of G.652 single-mode fiber with duplex LC connectors.

Q3: Can the 40G-LR4 transceiver be split into 4x10G connections?
No, 40G-LR4 cannot be split into 4x10G. The 40GBASE-LR4 uses 4 lambdas (or wavelengths) on a pair of single mode fibers, and does not lend itself to “splitting” into 4 pairs without substantial complexity to split out the wavelengths. The unique characteristic of 40GBASE-SR4 is that it uses parallel (ribbon) fiber, which allows the creation of 4 fiber pairs. As an alternative single mode parallel 40G optics are available (40G-PLRL4 and 40G-PLR4) that do allow for splitting into 4x10G (single mode).

Q4: How does the QSFP+ to SFP+ fiber convertor allow 4x 10G?
The IEEE 40G-SR4 standard specified a parallel technology, with 4 lanes in each direction. The purpose of this was to allow for easier development of 40G, re-using 10G components. As a side result the 40G multi-mode transceivers can also support 4x10G modes. A fiber that connects from one 40G port to four 10G ports provides a physical path to allow the source “40G” port running in 4x10G mode to be connected to 4 unique 10G destinations. As the fiber is a passive medium it has no concept of the 40G or 10G signals.

Fiberstore provides various types of 40G cables and transceivers including single-mode and multi-mode with different channels and wavelengths. All these transceivers are compatible with famous brands, like Brocade QSFP+, HP QSFP+, Juniper QSFP+, etc. They can also be customized to meet your special requirements.