Nowadays more and more fiber-based networks have been built in the backbone and risers environment. Both multimode and single-mode fibers are available for the applications. But different fiber types have briefly different limitations for speed and maximum distance. These characteristics they possess and the way cause the fiber to operate determine the application to which a given fiber is most appropriate. Today’s article will offer you some information about the classification of fiber optic cables and the difference in speed and distances.
Difference Between OM Multimode Fibers
Multimode fibers, according to the specification and briefly by their bandwidth performance are commonly classified into OM1, OM2, OM3 and OM4. Each multimode type has different transmission data rates, link length and bandwidth for specific protocols, applications and transceiver types. Table 1 outlines the international standards organization classification for multimode fiber which describe the strength for speed and distance.
From the above table, we can see that OM1 is the 62.5-micron fiber, while OM2/OM3/OM4 are the 50-micron multimode fibers. OM1 multimode fiber was used to be the most common multimode fibers in the 80’s and 90’s. However, it is generated accepted that OM1 will soon be obsolete for the lowest data carrying capacity and shortest distance limitations as compared with other multimode fibers. As for the 50-micron multimode fibers, they are the most commonly used fiber types today, especially the OM3 and OM4 cables. Why do the multimode fibers with a smaller diameter have better performance than the large one? Please read on.
In terms of the performance in 50-micron and 62.5-micron multimode fibers, the difference lies in the fibers’ bandwidth, or the signal-carrying capacity. Bandwidth is actually specified as a bandwidth-distance product with units of MHz-km that depends on the data rate. As the data rate goes up (MHz), the distance that rate can be transmitted (km) goes down. Thus, a higher fiber bandwidth can enable you to transmit at higher data rates or for longer distances. For example, 50-micron multimode fiber offers nearly three times more bandwidth (500 MHz-km) than FDDI-grade 62.5-micron fiber (160 MHz-km) at 850 nm.
While fiber bandwidth is a critical factor in determining link length and data rate, transmitter and receiver characteristics also matters. For 850-nm Gigabit Ethernet, these bandwidth values support link lengths of 220 meters over 62.5-micron fiber and 550 meters over 50-micron fiber. For example, Cisco GLC-SX-MM operating at 850-nm can support a link distance of 550 m over 50-micron fiber (OM2). Today, the 850-nm operating window is increasingly important, as low-cost 850-nm lasers such as verti cal-cavity surface-emitting lasers (VCSELs) are becoming widely available for network applications. VCSELs offer users the ability to extend data rates at a lower cost than long-wavelength lasers. Since 50-micron multimode fiber has higher bandwidth in the 850-nm window, it can support longer distances using these lower-cost VCSELs. Thus, 50-micron multimode fiber is more suitable for fiber backbones running Gigabit Ethernet and higher-speed protocols over longer distances.
Multimode vs. Single-mode Fibers
Single-mode fiber, owing to the more expensive electronics required in the network, is usually used for much greater-reach applications but not a cost-effective investment for future application in building. As the multimode fibers can be divided into OM1, OM2, OM3 and OM4 fiber types, single-mode fibers usually come in OS1 and OS2 fibers. For the detailed information, please look at the article “The Truth About OS1 and OS2 Optical Fiber”.
Jacket color is sometimes a simple method to distinguish multimode cables from single-mode ones. The standard TIA-598C recommends, for non-military applications, the use of a yellow jacket for single-mode fiber, and orange or aqua for multimode fiber, depending on type as you can seen in the Figure 2.
Besides the jacket color, the difference between multimode and single-mode optical fiber (9-mircon core) is that the former has much larger core diameter; much larger than the wavelength of the light carried in it. Because of the large core and the possibility of large numerical aperture, multimode fiber has higher “light-gathering” capacity than single-mode fiber. In practical terms, the larger core size simplifies connections and also allows the use of lower-cost electronics such as light-emitting diodes (LEDs) and vertical-cavity surface-emitting lasers (VCSELs) which operate at the 850 nm and 1300 nm wavelength (single-mode fibers used in telecommunications typically operate at 1310 or 1550 nm). However, compared to single-mode fibers, the bandwidth & distance product limit of multimode fiber is lower. Because multimode fiber has a larger core-size than single-mode fiber, it supports more than one propagation mode; hence it is limited by modal dispersion, while single mode is not.
The light sources used in these two cable types also plays a critical role in the performances. The LED light source sometimes used with multimode fiber produce a range of wavelengths and these each propagate at different speeds. This chromatic dispersion is another limit to the useful length for multimode fiber optic cable. In contrast, the lasers used to drive single-mode fibers produce coherent light of a single wavelength. Due to the modal dispersion, multimode fiber has higher pulse spreading rates than single mode fiber, limiting multimode fiber’s information transmission capacity. Thus, single-mode fibers are often used in high-precision scientific research because restricting the light to only one propagation mode allows it to be focused to an intense, diffraction-limited spot.
The growth in subscribers’ demand for more sophisticated electronics and web-connected services increases the requirement for information storage and cloud technology. End-users also want to know how to choose the right cable type for your network application. Therefore , I hope after reading this article you might have learned something from it.
As one of the latest and most popular technologies utilized for information transmission from one point to another, the fiber optic communication has gained more and more importance in data centers nowadays. Since its introduction, fiber optic communication has revolutionized the telecommunications industry, transforming into the fiber optic broadband Internet service enjoyed by people today. With the obvious advantages, fiber optic cables have become an essential component in fiber optic communications. Terminated with connectors on ends, these cables (e.g. SC SC fiber cable) carry the light signals generated by the transmitter to the receiver. Although this fiber optic connection has been widely used in data centers because of its high data transmission speeds over long distance, fiber optics, like many other things, also has two sides: the pros and cons. Here this article delves into the advantages and disadvantages of fiber optic networks.
Great Immunity & High-quality Connections: Since the fiber core is made of glass, which is an insulator, no electric current can flow through. It’s immune to electrometric interference and radio-frequency interference (EMI/RFI), crosstalk, impedance problems, and more. More specifically, fiber optics are highly resistant to EMI and have a low rate of bit error. EMI is a disturbance caused by electromagnetic radiation from an external source. This disturbance can interrupt or degrade the performance of a conventional metallic cable connection and can be caused by an object that carries electrical currents, such as power lines or even the sun. Fiber optics are also resistant to corrosion, making them a good option for beachfront properties where copper cabling would otherwise be susceptible to degradation by salt and seawater.
Great Security: Security is a major concern for some companies, enterprises or organizations, whether small or big. With fiber optic cables, the data carried on are very safe. Fiber optics don’t radiate signals and it’s really difficult to tap or listen in the passed through information. Besides, once there occurs any physical break, it’s extremely to identify since this break will have impacts on the whole system. Fiber optic networks also enable you to put all your electronics and hardware in one central location, instead of having wiring closets with equipment throughout the building.
Scalability & Design: Fiber optics are much more scalable in nature as new equipment can be added easily and laid over the original fiber. Wavelengths can be turned on or off on demand, which allows for the easy provisioning of services and quick scaling for a growing business. Fiber optic cables are also much smaller in size and lighter weight than copper wiring. These fibers can typically be put in place in preparation for growth needs up to 15 to 20 years in the future. Although growth is often speculative, spare fibers can be included for future requirements to accommodate growth. Alternatively, additional cables can be put in place at a later time to make way for network expansion.
It’s well known that fiber optic cable provides more bandwidth than copper, and can carry more information with greater fidelity than copper wire. And no one can defy its advantages. But it’s also clear that fiber optic networks have several weak points.
Physical Damage: As mentioned above, fiber optic cable is thinner and lighter than copper wiring, so it makes for a more delicate system. Just because of its small size, fiber optic cable can be easily cut by accident during building renovations or rewiring. In addition, as fiber optic cables can transmit much more data than metallic networks, you would need fewer cables to service a larger number of people. This means that cutting just one cable could disrupt service for a large number of businesses and individuals. Additionally, wildlife also poses a threat, as the fiber cable jackets are intriguing to some species. Tunneling animals and rodents may chew through the cable, while many insects can find the cabling palatable. Anything that can wrap itself around the cable can also cut off the transmission. Fibers are also sensitive to bending, making laying fibers around corners a tricky business. Fiber optic networks are also susceptible to radiation damage or chemical exposure.
Fiber Fuse: At high power, fiber optic networks are susceptible to something known in the industry as “fiber fuse”. This occurs when too much light meets with an imperfection in the fiber, which can destroy long lengths of cable in a short amount of time.
Short-Term Large Budget: Judging from the long-term running, it’s cost-effective. But when considering for short-term use, it’s costly to implement fiber optic systems. Special test equipment is often required along with installers that have skilled knowledge about laying a fiber optic network. Fiber endpoints and connection nexuses also require special equipment and setup. In addition, it may take specialized equipment to diagnose an issue with a fiber optics network, making for higher-cost fixes if the cables sustain damage.
Although there some several weaknesses, fiber optics technology has still dominated the telecommunication market. And fiber optic network is selected as the main communication way. To ensure efficient fiber optic network, it’s important to choose the high-quality fiber optic products. Here Fiberstore is highly recommended for its reliable products, including optical transceivers (say SFP modules), fiber optic cables (SC SC fiber cable), as well as testing equipment used in cable installation, and so on. You can try it!