With OM3, Will OM4 Still Be Needed?

With the transmission of massive amount of data, there is an increasing demand for higher bandwidth and fast speeds. The basic structure of network—cabling should be upgraded accordingly to meed this demand. For instance, copper cabling is developed from Category 1 to Category 8 cable. Likewise, fiber optic cabling also has its improvement, especially the multimode fibers that have OM1, OM2, OM3 and OM4 cables. OM1 specifies 62.5-micron cable and OM2 specifies 50-micron cable, while OM3 and OM4 are the optimized upgrade of OM2 for higher bandwidth applications, such as 40/100 GbE. However, a lot of confusion has emerged as the use of OM3 and OM4 fiber coexist. OM3 and OM4 seem to have many similarities and same applications. So why do we still need OM4 though we have already had OM3?

Similarities of OM3 and OM4

Both OM3 and OM4 are laser-optimized multimode fiber (LOMMF) and were developed to accommodate faster networks such as 10, 40 and 100 Gbps. They have the same fiber core size 50/125 and the termination of the connections is the same. Moreover, both of them are designed for use with 850nm VCSELS (vertical-cavity surface-emitting lasers) and have aqua sheaths. The picture below is a 10G OM4 SC LC fiber patch cable.

Difference Between OM3 and OM4

With the better fiber cable construction, OM4 fiber (4,700 megahertz) operates at higher bandwidth than OM3 (2,500 megahertz). The higher bandwidth available in OM4 refers to a smaller modal dispersion and thus allows for longer cable links or higher losses through more mated connectors. This provides more options when looking at network design. Besides, OM4 cable has better attenuation that leads lower losses than OM3. The lower losses mean that we have longer links or have more mated connectors in the link.

Actually, the factors that we describe above translate to longer transmission distances for the OM4 fiber. Although OM3 and OM4 can be both applied to 10GbE, 40GbE and 100GbE applications, they have different transmission distance. For 10G network, OM3 can transmit 300 m, while OM4 can transmit 500 m. For 40G and 100G network, OM3 supports 100 m, but OM4 supports 150 m. So OM4 has a better performance than OM3 due to its better cable construction. The primary cost increase of OM4 arises from this. The cost for OM4 is greater due to the manufacture process. Generally, OM4 cable is about twice as expensive as OM3 cable.

OM4 is a laser-optimized, high bandwidth 50 micrometer multimode fiber. In August of 2009, TIA/EIA approved and released 492AAAD, which defines the performance criteria for this grade of optical fiber. It can be used to enhance the system cost benefits enabled by 850 nm VCSELs for the earlier 1 G and 10 Gb/s applications as well as the 40 and 100 Gb/s systems. For example, most of ST to LC fiber jumper from FS.COM is manufactured using laser-optimized, 50/125, OM4 multimode cable, and can achieve max link distance of 50 meters. OM4 fiber can support Ethernet, Fibre Channel, and OIF applications, allowing extended reach upwards of 550 meters at 10 Gb/s for ultra long building backbones and medium length campus backbones. OM4 fiber is also especially well suited for shorter reach data center and high performance computing applications.

Except cost consideration, the availability of standard is the other consideration on using OM3 or OM4. OM3 is much more widely used than OM4 because there is a greater range and depth of standard product available. However, for factory manufactured pre-terminated solutions, the availability is now similar due to the increase in the demand for 40 GbE and 100 GbE. Additionally, OM3 and OM4 are completely compatible. So it is completely viable to mix OM3 product with OM4 and still obtain the required performance.

Conclusion

It is important to note that OM4 glass is not necessarily designed to be a replacement for OM3. Despite the relatively long-standing availability of OM4, there are no plans to obsolete OM3 fiber optic cabling. For most systems, OM3 glass is sufficient to cover the bandwidth needs at the distances of the current installation base. Most system requirements can still be reliably and cost effectively achieved with OM3, and this glass type will remain available for the foreseeable future. Despite the availability of OM4 glass, OM3 is quite capable of 40 and 100 Gb/s applications albeit at significantly shorter distances than OM4. This is why we need OM4 though we have already had OM3. All in all, which one to choose should depend on the network/distance design and cost as well as the future migration plan of your network.

Introduction to Single-mode Fiber Patch Cords

A fiber optic patch cord is a fiber optic cable capped at either end with connectors that allow it to be rapidly and conveniently connected to CATV, an optical switch or other telecommunication equipment. With a thick layer of protection, patch cords are usually used to connect the optical transmitter, receiver as well as the terminal box. It is widely accepted that in terms of transmission medium, the fiber patch cords can be defined into two categories: single-mode fiber patch cords and multimode fiber patch cords. This article will introduce the single-mode fiber patch cords from the following aspects.

What Is Single-mode Fiber Patch Cords

Single-mode fiber patch cords contain a small core of 9/125 um and have only one pathway of light. Instead of simply bouncing the light of the edge of the core, the single-mode patch cords realign the light toward the center of the core with only a single wavelength of light passing through its core. Generally, the color of single-mode fiber patch cord is yellow. It is most often used in long-distance, high bandwidth network connections spread out over extended areas, usually longer than a few miles.

Features of Single-mode Fiber Patch Cords

Single-mode fiber patch cords can achieve lower attenuation and thus obtain the ability for the signal to travel faster and further. Besides, it also has several other advantages: 1. Low insertion loss and high return loss 2. Excellent environmental adaptability 3. Good performance endurance under changing circumstance 4. Higher speed data transmission with longer distance 5. Simplex and duplex assemblies

Types of Single-mode Fiber Patch Cords

As for the types of single-mode fiber patch cords, classified by connector construction, they can be divided into LC, FC, SC, ST, MTRJ, E2000 and MU fiber patch cords, etc. Each of these single-mode fiber patch cords are available both in simplex and duplex patch cords. So, the following part will focus on the introduction to simplex and duplex single-mode fiber patch cords.

• Simplex Single-mode Fiber Patch Cords Simplex single-mode fiber patch cords consist of a single strand of glass or plastic fiber. It is generally adopted in devices where only a single transmit and/or receive line is required, which means the data barely send in one direction. For instance, TV and radio broadcasting employed simplex fiber patch cords to achieve one direction signal transfer. During the process, information flows only from the transmitter to multiple receivers. The picture below is a SC-SC simplex single-mode fiber patch cable.
• Duplex Single-mode Fiber Patch Cords Duplex single-mode fiber patch cords consist of two strands of glass or plastic fiber. It is often seen in a zipcord construction format. A duplex fiber patch cable can be regarded as two simplex cables having their jackets conjoined by a strip of jacket material. This kind of patch cable is mostly used for duplex communication that a separate transmit and receive are required between devices, which indicates that these two connected parties can communicate with each other in both directions. Duplex fiber patch cords are usually adopted in the field of telecommunication. The picture below is a LC-SC duplex single-mode fiber patch cable.

Applications of Single-mode Fiber Patch Cords

As mentioned above, the single-mode fiber patch cord is often used to achieve long-distance and high bandwidth data transmission with little integrity loss. This type of cable is extensively adopted in telecommunication network, high speed metropolitan access network as it supports high speed multi channel video, data and voice services.

Conclusion

There are still many other factors that should be taken into account when choosing the suitable patch cords. As a leading fiber optic patch cord manufacturer in China, FS.COM offers a large quantity of single-mode fiber patch cords with the coverage of all the types. To learn more about single-mode fiber patch cords, please kindly visit the website at www.fs.com or contact via sales@fs.com.

Single-mode Fiber Patch Cable vs. Multimode Fiber Patch Cable

Fiber patch cable, also known as fiber optic jumper or fiber optic patch cord, is designed to interconnect or cross connect fiber networks within structured cabling systems. The connectors capped at either end of the fiber patch cable allow it to be rapidly and conveniently connected to an optical switch, cable television (CATV) or other telecommunication equipment. Depending on transmission medium, the fiber patch cable can be classified into single-mode fiber patch cable and multimode fiber patch cable.

What Is Single-mode Fiber Patch Cable

Single-mode fiber patch cables or single mode fiber jumpers are generally yellow. They are composed of one fiber optic cable terminated with single mode fiber optic connectors at both ends. It is usually used for connections over large areas, such as college campuses and cable television networks. Compared with multimode fiber patch cable, single-mode fiber patch cable have a higher bandwidth. The following figure shows the common single-mode fiber patch cable which is with blue connectors at both ends.

What Is Multimode Fiber Patch Cable

Multimode fiber patch cable, which is generally orange or grey, is composed of a fiber optic cable terminated with multimode fiber optic connectors at both ends. Its connectors are generally cream or black (as shown below). Due to the high capacity and high reliability, multi-mode fiber patch cables are a good choice for transmitting data and voice signals over shorter distances. They are typically used for data and audio/visual applications in local-area networks and connections within buildings.

Difference Between Single-mode and Multimode Fiber Patch Cables

The main difference between single-mode and multimode patch cable is the size of their respective cores.

Single-mode fiber optic patch cables use 9/125 (“9″ represents the diameter of the core, and “125” represents the diameter of the cladding) micron bulk single-mode fiber cables. The most common type of single-mode fiber has a core diameter of 8 to 10 microns. In single-mode cables, light travels toward the center of the core in a single wavelength, allowing the signal to travel faster and over longer distances without a loss of signal quality than is possible with multimode cabling.

Multimode fiber patch cables use 62.5/125 (“62.5″ represents the diameter of the core, and “125” represents the diameter of the cladding) micron or 50/125 (“50″ represents the diameter of the core, and “125” represents the diameter of the cladding) micron multimode fiber cables. In other words, the core of the multimode fiber patch cable is either 50 or 62.5 microns. Compared with single-mode cable, the larger core of the multimode cable gathers more light, and this light reflects off the core and allows more signals to be transmitted. Although it is more cost-effective than single-mode cable, the multimode cabling does not maintain signal quality over long distances.

In conclusion, both single-mode fiber patch cable and multimode fiber patch cable have their respective applications. They can be used in computer work station to outlet and patch panels or optical cross connect distribution center. Whether to choose single mode or multimode depends on many factors, like the applications, the distance requirement, the budge, etc.

Which Kind of Single-mode Fiber Should You Choose?

Fiber optic terminology often seem to be a bit like alphabet soup, but I’m sure you already knew that. What you may not know is how to decide on the best single-mode fiber for your particular fiber optic network. Each type of single-mode fiber has its own area of application and the evolution of these optical fiber specifications reflects the evolution of transmission system technology from the earliest installation of single-mode optical fiber until today. In this post, I may explain a bit more about the differences between the specifications of the G.65x series of single-mode optical fiber families.

As is know to all, multimode fiber is usually divided into OM1, OM2, OM3 and OM4. But the types of single-mode fiber is much more complex. There are mainly two specifications of single-mode optical fiber. One is the ITU-T G.65x series, and the other is IEC 60793-2-50 (published as BS EN 60793-2-50). This purpose of this article is to introduce ITU-T G.65x series single-mode fiber.

Name	Type
ITU-T G.652	ITU-T G.652.A, ITU-T G.652.B, ITU-T G.652.C, ITU-T G.652.D
ITU-T G.653	ITU-T G.653.A, ITU-T G.653.B
ITU-T G.654	ITU-T G.654.A, ITU-T G.654.B, ITU-T G.654.C
ITU-T G.655	ITU-T G.655.A, ITU-T G.655.B, ITU-T G.655.C, ITU-T G.655.D, ITU-T G.655.E
ITU-T G.656	ITU-T G.656
ITU-T G.657	ITU-T G.657.A, ITU-T G.657.B, ITU-T G.657.C, ITU-T G.657.D

G.652

The ITU-T G.652 fiber is also known as standard SMF (single-mode fiber) and is the most commonly deployed fiber. It comes in four variants (A, B, C, D). A and B have a water peak. C and D eliminate the water peak for full spectrum operation. The G.652.A and G.652.B fibers are designed to have a zero-dispersion wavelength near 1310 nm, therefore they are optimized for operation in the 1310-nm band. They can also operate in the 1550-nm band, but it is not optimized for this region due to the high dispersion. These optical fibers are usually used within LAN, MAN and access network systems. The more recent variants (G.652.C and G.652.D) feature a reduced water peak that allows them to be used in the wavelength region between 1310 nm and 1550 nm supporting Coarse Wavelength Division Multiplexed (CWDM) transmission.

G.653

G.653 fiber was developed to address this conflict between best bandwidth at one wavelength and lowest loss at another. It uses a more complex structure in the core region and a very small core area, and the wavelength of zero chromatic dispersion was shifted up to 1550 nm to coincide with the lowest losses in the fiber. Therefore, G.653 fiber is also called dispersion-shifted fiber (DSF). G.653 has a reduced core size, which is optimized for long-haul single-mode transmission systems using erbium-doped fiber amplifiers (EDFA). However, its high power concentration in the fiber core may generate nonlinear effects. One of the most troublesome, four-wave mixing (FWM), occurs in the CWDM system with zero chromatic dispersion, causing unacceptable crosstalk and interference between channels.

G.654

The G.654 specification uses a larger core size made from pure silica to achieve the same long-haul performance with low attenuation in the 1550-nm band. It usually also has high chromatic dispersion at 1550 nm, but is not designed to operate at 1310 nm at all. G.654 fiber can handle higher power levels between 1500 nm and 1600 nm, which is mainly designed for extended long-haul undersea applications.

G.655

G.655 is known as non-zero dispersion-shifted fiber (NZDSF). It has a small, controlled amount of chromatic dispersion in the C-band (1530-1560 nm), where amplifiers work best, and has a larger core area than G.653 fiber. NZDSF fiber overcomes problems associated with four-wave mixing and other nonlinear effects by moving the zero-dispersion wavelength outside the 1550-nm operating window. There are two types of NZDSF, known as (-D)NZDSF and (+D)NZDSF. They have respectively a negative and positive slope versus wavelength. Following picture depicts the dispersion properties of the four main single-mode fiber types. The typical chromatic dispersion of a G.652 compliant fiber is 17ps/nm/km. G.655 fibers were mainly used to support long-haul systems that use DWDM transmission.

G.656

As well as fibers that work well across a range of wavelengths, some are designed to work best at specific wavelengths. This is the G.656, which is also called Medium Dispersion Fiber (MDF). It is designed for local access and long haul fiber that performs well at 1460 nm and 1625 nm. This kind of fiber was developed to support long-haul systems that use CWDM and DWDM transmission over the specified wavelength range. And at the same time, it allow the easier deployment of CWDM in metropolitan areas, and increase the capacity of fiber in DWDM systems.

G.657

G.657 optical fibers are intended to be compatible with the G.652 optical fibers but have differing bend sensitivity performance. It is designed to allow fibers to bend, without affecting performance. This is achieved through an optical trench that reflects stray light back into the core, rather than it being lost in the cladding, enabling greater bending of the fiber. As we all know, in cable TV and FTTH industries, it is hard to control bend radius in the field. G.657 is the latest standard for FTTH applications, and, along with G.652 is the most commonly used in last drop fiber networks.

Choosing the right one for your project can be vital in terms of performance, cost and reliability of the optic fiber assemblies, such as fiber jumper or fiber optic cable. Different kind of single-mode fiber has different application. Since G.657 is compatible with the G.652, some planners and installers are usually likely to come across them. In fact, G657 has a larger bend radius than G.652, which is especially suitable for FTTH applications. And due to problems of G.643 being used in WDM system, it is now rarely deployed, being superseded by G.655. G.654 is mainly used in subsea application.

Originally published at http://www.fs.com/blog