分类目录归档:Fiber Optic Cable

OM1, OM2, OM3, OM4 and OS2 Over Different Networks

When selecting fiber optic cables or fiber optic patch cords, the factor that you must consider is the fiber type. The most commonly used fiber type in today’s network are multimode fiber optic and single-mode fiber optic. The multimode optical fiber can be further divided into OM1, OM2, OM3 and OM4. For single-mode fiber optic, there are generally two types—OS1 and OS2. Among these different types of fibers, OM1, OM2, OM3, OM4 and OS2 are the most commonly used one.

 what are OM1, OM2, OM3, OM4 and OS2: OM3 and OS2 patch cords

Fiber Type Is Important to Fiber Optic Network Performance

Apparently different types of the optical fibers provide different performances. Multimode fibers are typically used for inside building or short transmission distances. OM1 and OM2 are the older generation of multimode optical fibers with work well over fast Ethernet and Gigabit Ethernet. However, with the appearance of 10G, 40G and 100G Ethernet coming into being, OM1 and OM2 can no longer provide performance as well as fast Ethernet or Gigabit Ethernet and can not satisfy the transmission distance requirements. That’s why OM3 and OM4 are created. Similarly, the appearance of OS2 is also well explained.

Basic Difference of OM1, OM2, OM3, OM4 and OS2

Generally, OM1 fiber optic cable comes with an orange jacket and has a core size of 62.5 micrometers and is usually used for Gigabit Ethernet transmission in short-haul networks, Local Area Network, and Private Network. OM2 has the same jacket color and similar application as OM1. However, it can has a core size of 50.0 micrometers and support longer transmission distance. Both OM3 and OM4 are designed with Aqua jackets and 50.0 micrometers core size and are suggested for 10G, 40G and 100G Ethernet. Now OM1 and OM2 are gradually being replaced by OM3 and OM4. OS2 is the currently widely deployed in our fiber optic network, it has a core size of 9 micrometers.

Specific Performance of OM1, OM2, OM3, OM4 and OS2 Over Different Networks

Not matter what the structure or materials that makes these optical fibers, what we care most is the performance in fiber optic network. Especially factors like transmission distance, wavelength and data rate. For instance, the same type of fiber optic cable will have different performance when working on different data rate or wavelengths. Fiber type plays an important role in the performance of optical communication products like fiber optic transceivers, fiber media converters and DWDM/CWDM MUX/DEMUX. This part will provide several tables which offer the specific performances of the current most popular optical fibers—OM1, OM2, OM3, OM4 and OS2.

OM1 Performance

OM1 Performance
Wavelength
850 nm
1300 nm
Performance
Distances
Loss Budget(dB)
Distances
Loss Budget(dB)
Ethernet
2000m
n/s
n/s
n/s
Fast Ethernet
300m
11
2000m
11
1GbE
275m
3.6
550m
3.6
10GbE
26m
2.6
n/s
2.6
40GbE
n/s
1.9
n/s
1.9
100GbE
n/s
1.9/1.5
n/s
1.9/1.5
Typical Bandwidth
200MHz
500MHz

OM2 Performance

OM2 Performance
Wavelength
850 nm
1300 nm
Performance
Distances
Loss Budget(dB)
Distances
Loss Budget(dB)
Ethernet
2000m
n/s
n/s
n/s
Fast Ethernet
300m
11
2000m
11
1GbE
550m
3.6
550m
3.6
10GbE
82m
2.6
82m
2.6
40GbE
n/s
1.9
n/s
1.9
100GbE
n/s
1.9/1.5
n/s
1.9/1.5
Typical Bandwidth
500MHz
800MHz

OM3 Performance

OM3 Performance
Wavelength
850 nm
1300 nm
Performance
Distances
Loss Budget(dB)
Distances
Loss Budget(dB)
Ethernet
2000m
n/s
n/s
n/s
Fast Ethernet
300m
11
2000m
11
1GbE
550m
3.6
550m
3.6
10GbE
300m
2.6
300m
2.6
40GbE
100m
1.9
n/s
1.9
100GbE
100m
1.9/1.5
n/s
1.9/1.5
Typical Bandwidth
1500MHz
500MHz

OM4 Performance

OM4 Performance
Wavelength
850 nm
1300 nm
Performance
Distances
Loss Budget(dB)
Distances
Loss Budget(dB)
Ethernet
n/s
n/s
n/s
n/s
Fast Ethernet
n/s
11
n/s
11
1GbE
550m
3.6
550m
3.6
10GbE
550m
2.6
550m
2.6
40GbE
150m
1.9
n/s
1.9
100GbE
150m
1.9/1.5
n/s
1.9/1.5
Typical Bandwidth
3500MHz
500MHz

OS2 Performance

OS2 Performance
Wavelength
1310 nm
1550 nm
Performance
Distances
Loss Budget(dB)
Distances
Loss Budget(dB)
Ethernet
n/s
n/s
n/s
n/s
Fast Ethernet
n/s
11
n/s
11
1GbE
5000m
3.6
n/s
3.6
10GbE
10000m
2.6
40000m
2.6
40GbE
10000m
1.9
40000m
1.9
100GbE
10000m
1.9/1.5
40000m
1.9/1.5
Typical Bandwidth
n/a
n/a

Kindly contact sale@fs.com or visit FS.COM for more details about OM1, OM2, OM3, OM4 and OS2.

Related Articles: Migrating to 40/100G With OM3/OM4 Fiber
                               Single Mode vs Multimode Fiber: What’s the Difference?

Understanding Losses in Optical Fiber

Fiber optic transmission has various advantages over other transmission methods like copper or radio transmission. Fiber optic cable which is lighter, smaller and more flexible than copper can transmit signals with faster speed over longer distance. However, many factors can influence the performance of fiber optic. To ensure the nice and stable performance of the fiber optic, many issues are to be considered. Fiber optic loss is a negligible issue among them, and it has been a top priority for many engineers to consider during selecting and handling fiber optic. This article will offer detailed information of losses in optical fiber.

light-in-fiber-optic

When a beam of light carrying signals travels through the core of fiber optic, the strength of the light will become lower. Thus, the signal strength becomes weaker. This loss of light power is generally called fiber optic loss or attenuation. This decrease in power level is described in dB. During the transmission, something happened and causes the fiber optic loss. To transmit optical signals smoothly and safely, fiber optic loss must be decreased. The cause of fiber optic loss located on two aspects: internal reasons and external causes of fiber optic, which are also known as intrinsic fiber core attenuation and extrinsic fiber attenuation.

Intrinsic Fiber Core Attenuation

Internal reasons of fiber optic loss caused by the fiber optic itself, which is also usually called intrinsic attenuation. There are two main causes of intrinsic attenuation. One is light absorption and the other one is scattering.

Light absorption is a major cause of losses in optical fiber during optical transmission. The light is absorbed in the fiber by the materials of fiber optic. Thus light absorption in optical fiber is also known as material absorption. Actually the light power is absorbed and transferred into other forms of energy like heat, due to molecular resonance and wavelength impurities. Atomic structure is in any pure material and they absorb selective wavelengths of radiation. It is impossible to manufacture materials that are total pure. Thus, fiber optic manufacturers choose to dope germanium and other materials with pure silica to optimize the fiber optic core performance.

Scattering is another major cause for losses in optical fiber. It refers to the scattering of light caused by molecular level irregularities in the glass structure. When the scattering happens, the light energy is scattered in all direction. Some of them is keeping traveling in the forward direction. And the light not scattered in the forward direction will be lost in the fiber optic link as shown in the following picture. Thus, to reduce fiber optic loss caused by scattering, the imperfections of the fiber optic core should be removed, and the fiber optic coating and extrusion should be carefully controlled.

Extrinsic Fiber Attenuation

scattering in fiber optic

Intrinsic fiber core attenuation including light absorption and scattering is just one aspect of the cause in fiber optic loss. Extrinsic fiber attenuation is also very important, which are usually caused by improper handling of fiber optic. There are two main types of extrinsic fiber attenuation: bend loss and splicing loss.

macro bend VS. micro bend

Bend loss is the common problems that can cause fiber optic loss generated by improper fiber optic handling. Literally, it is caused by fiber optic bend. There are two basic types. One is micro bending, and the other one is macro bending (shown in the above picture). Macro bending refers to a large bend in the fiber (with more than a 2 mm radius). To reduce fiber optic loss, the following causes of bend loss should be noted:

  • Fiber core deviate from the axis;
  • Defects of manufacturing;
  • Mechanical constraints during the fiber laying process;
  • Environmental variations like the change of temperature, humidity or pressure.

fiber optic splicing is another main causes of extrinsic fiber attenuation. It is inevitable to connect one fiber optic to another in fiber optic network. The fiber optic loss caused by splicing cannot be avoided, but it can be reduced to minimum with proper handling. Using fiber optic connectors of high quality and fusion splicing can help to reduce the fiber optic loss effectively.

types of losses in optical fiber

The above picture shows the main causes of losses in optical fiber, which come in different types. To reduce the intrinsic fiber core attenuation, selecting the proper fiber optic and optical components is necessary. To decrease extrinsic fiber attenuation to minimum, the proper handling and skills should be applied.

Related articles: How to Reduce Various Types of in Optical Fiber?

Lower FTTH Cost and Increase Reliability With Tight Buffer Indoor/Outdoor Cable

FTTH (Fiber to the Home) network connects a large number of end users to a central point known as an access node to provide the application and services of high speed. The links between end users and access node are achieved largely by fiber optic cables. Loose buffer cables and tight buffer cables are commonly used to transmit signals with high speed, which are capable of surviving outdoor environment or indoor environment. However, to accomplish the whole transmission link, loose buffer cables for outdoor application should be connected with the tight buffer cables for indoor application. The splicing and termination of these fiber optic cables come as one of the largest link items in a FTTH system installation budget.

Is There A Better FTTH Cable Solution?

Is there a cost-effective and time-saving solution by using a single type of cable that can survive both indoor and outdoor environment in FTTH network? The answer is YES. Tight buffer indoor/outdoor cable is such a cable. It is a specially designed tight buffer cable which can answer the market call for a single type cable surviving both indoor and outdoor environment. To understand why it is a better choice for FTTH installation, the construction and comparison of loose tube cable and tight buffer cable will be introduced firstly.

Loose Buffer VS Tight Buffer

The “buffer” previously mentioned in “loose buffered” and “tight buffer” is actually a basic component of fiber optic cable and the first layer used to define the type of cable construction. A typical fiber optic cable consists of the optical fiber, buffer, strength members and an outer protective jacket (as showed in the following picture). The buffer literally is used to provide protection and some tensile strength, which are useful when pulling the cable to install it or when it must hang between two suspension points.

cable structure

Loose buffer cable consists of a buffer layer that has an inner diameter much larger than the diameter of the fiber (showed in the following picture). Thus, the cable will be subject to temperature extremes that cause expansion or contraction. That’s why loose buffered cable are usually used outdoor. The loose buffer cables designed for FTTH outdoor application are usually loose-tube gel-filled cables (LTGF cable). This type of cable is filled with a gel that displaces or blocks water and prevents it from penetrating or getting into the cable.

loose buffer cable

Tight buffer cable using a buffer attached to the fiber coating is generally smaller in diameter than loose buffer cable (showed in the following picture). The minimum bend radius of a tight buffer cable is typically smaller than a comparable loose buffer cable. Thus tight buffer cable is usually used in indoor application.

tight buffer

Tight buffered indoor/outdoor cable with properly designed and manufactured can meet both indoor and outdoor application requirements. It?combines the design requirements of traditional indoor cable and adds moisture protection and sunlight-resistant function to meet the standards for outdoor use. Tight buffered indoor/outdoor cable?also meets one or more of the code requirements for flame-spread resistance and smoke generation.

A Better Choice for FTTH Cable Solution

The structure and performance advantages of tight buffer indoor/outdoor cable have been introduced above. How about the other advantages? The following will explain why tight buffered indoor/outdoor cable is a better FTTH cable solution from the aspects of cost and reliability.

Cost

Using the traditional choice of LTGF cables as the outdoor cable, there would be a conversion from one fiber type from another type, which includes prep work on the fiber, the need for splice tray, the routing of fibers in the tray, and other similar detail. Before termination and splicing, the gel of LTGF cable must be cleaned and the breakout point of the main cable must be blocked by some method to prevent oozing of the cable gel. In addition, this cable type must normally be terminated or spliced close to the cable entryway of a building to switch to indoor cable, as it generally incompatible with indoor fiber codes. This time consuming and labor intensive process adds hidden costs to install the LTGF cables.

However, using only tight buffer indoor/outdoor cable for FTTH is much more convenient and cost-effective. A tight-buffered indoor/outdoor cable can be used throughout the link, requiring no transitions at the building entryway. Tight buffer indoor/outdoor cable requires less care to avoid damaging fibers when stripping back the cable. The termination and splicing of these cables are easier than that of LTGF cables.

Reliability

An important reason why choose tight-buffered indoor/outdoor cable for FTTH cable installation is the reliability of the overall system. Splicing are the weakest point in a FTTH network. With splicing, the bare fiber ends are open to dust, dirt, water, vapor, and handing which might reduce the fiber strength and increase brittleness. Choosing loose tube outdoor cable for FTTH, there will be splices after the conversion from one cable type to another type. The splices inside a building may be held in a cabinet that is open to the air, which might decrease the reliability of the FTTH network. Using the tight buffer indoor/outdoor cable could eliminate splicing and improve the installation reliability greatly.

Conclusion

In conclusion, the benefits of tight buffer indoor/outdoor cable are clear. The installer can run a single cable type and remove a transition point between the outside plant and the inside plant, which decrease FTTH installation cost and time effectively. At the same time, the reliability of the overall FTTH network can be increased greatly.

Source: http://www.fs.com/blog/lower-ftth-cost-and-increase-reliability-with-tight-buffer-indooroutdoor-cable.html

Drop Cable and Its Termination in FTTH

FTTH (fiber to the home) networks are installed in many areas covering indoor section, outdoor section, as well as the transition in between. To fulfill the cabling requirements from different areas, different types of fiber optic cable are well developed. Drop cable as an important part of FTTH network forms the final external link between the subscriber and the feeder cable. This blog post will focus on this special outdoor fiber optic cable.

The Basic of FTTH Drop Cable

Drop cables, as previously mentioned, are located on the subscriber end to connect the terminal of a distribution cable to a subscriber’s premises. They are typicality small diameter, low fiber count cables with limited unsupported span lengths, which can be installed aerially, underground or buried. As it is used in outdoor, drop cable shall have a minimum pull strength of 1335 Newtons according to the industry standard. Drop cables are available in many different types. The following part introduces three most commonly used drop cables divided according to the cable structure.

Flat Type Drop Cable, also known as flat drop cable, with a flat out-looking, usually consists of a polyethylene jacket, several fibers and two dielectric strength members to give high crush resistance. Drop cable usually contains one or two fibers, however, drop cable with fiber counts up to 12 or more is also available now. The following picture shows the cross section of a flat drop cable with 2 fibers.

flat drop cable

Figure-8 Aerial Drop Cable is self-supporting cable, with the cable fixed to a steel wire, designed for easy and economical aerial installation for outdoor applications. This type of drop cable is fixed to a steel wire as showed in the following picture. Typical fiber counts of figure-8 Drop Cable are 2 to 48. Tensile load is typically 6000 Newtons.

Figure-8 Aerial Drop Cable

Round Drop Cable usually contains a single bend-insensitive fiber buffered and surrounded by dielectric strength members and an outer jacket, which can provide durability and reliability in the drop segment of the network. The following shows the cross section of a round drop cable with one tight buffered optical fiber.

round drop cable

Drop Cable Connectivity Method: Splice or Connector?

It’s necessary to choose a right architecture for FTTH network from overall. However, drop cable as the final connection from the fiber optic network to customer premises also plays an important role. Thus, finding a flexible, efficient and economical drop cable connectivity method becomes a crucial part of broadband service. Whether to use a fiber optic connector, which can be easily mated and un-mated by hand or a splice, which is a permanent joint? The following will offer the answer and the solutions for your applications.

It is known that splice, which eliminates the possibility of the connection point becoming damaged or dirty with a permanent joint, has better optical performance than fiber optic connector. However, splice lack of operational flexibility compared with fiber optic connector. Fiber optic connector can provide an access point for networking testing which cannot be provided by splicing. Both methods have their own pros and cons.

Generally, splice is recommended for drop cables in the places where no future fiber rearrangement is necessary, like a greenfield, new construction application where the service provider can easily install all of the drop cables. Fiber optic connector is appropriate for applications which flexibility is required, like ONTs which have a connector interface.

Choosing the Right Splice Method

For splice, there are two methods, one is fusion splicing, the other is mechanical splicing. Fusion splicers have been proved to provide a high quality splice with low insertion loss and reflection. However, the initial capital expenditures, maintenance costs and slow installation speed of fusion splicing hinder its status as the preferred solution in many cases. Mechanical splicing are widely used in FTTH drop cable installation in countries, as a mechanical splice can be finished in the field by hand using simple hand tools and cheap mechanical splicer (showed in the following picture) within 2 minutes. It’s a commonly used method in many places, like China, Japan and Korea. However, in US mechanical splicing is not popular.

FTTH Drop Cable Mechanical Splicer

Choosing the Right Connector

For fiber optic connector, there are two types connector for drop cable connection. Field terminated connector, which contains fuse-on connector and mechanical connector, and pre-terminated drop cable, which is factory terminated with connector on the end of drop cable.

Fuse-on connector uses the same technology as fusion splicing to provide the high optical connection performance. However, it requires expensive equipment and highly trained technician, and more time like fusion splicing. Mechanical connector could be a replacement of fuse-on connector (showed in the following picture), if the conditions do not fit the mentioned ones. It could be a time-save and cost-save solution for drop cable termination.

fuse-on connector

If you have no limits in cost and want high performance termination in a time-save way, pre-terminated drop cable could be your choice. Many factories can provide you customized drop cables in various fiber types, fiber optic connector and lengths.

Conclusion

Customer demand for higher bandwidth will continue to drive the development of FTTH as well as its key component like drop cable. Choosing the right drop cable and drop cable termination method is as important as choosing the right network architecture in FTTH.

Source: http://www.fs.com/blog/drop-cable-and-its-termination-in-ftth.html

Understanding MPO Cable and Polarity

MPO/MTP technology, which is of high density, flexibility and reliability with scalable, upgradeable properties, is one of the contributors that lead the migration to 40/100GbE. However, the network designers face another challenge which is how to assure the proper polarity of these array connections using multi-fiber MPO/MTP components from end-to-end. Maintain the correct polarity across a fiber network ensures that a transmit signal from any type of active equipment will be directed to receive port of a second piece of active equipment – and vice versa. To ensure the MPO cable work with correct polarity, the TIA 568 standard provided three methods, which will be introduced in this article.

MPO Connector

To understand the polarity in 40/100 GbE Transmission, the key of MPO technology—MPO cable connector should be first introduced. MPO connector usually has 12 fibers. 24 fibers, 36 fibers and 72 fibers are also available. Each MTP connector has a key on one of the flat side added by the body. When the key sits on the bottom, this is called key down. When the key sits on top, this is referred to as the key up position. In this orientation, each of the fiber holes in the connector is numbered in sequence from left to right and is referred as fiber position, or P1, P2, etc. A white dot is additionally marked on one side of the connector to denote where the position 1 is. (shown in the following picture) The orientation of this key also determines the MPO cable polarity.

MPO cable connector

Three Cables for Three Polarization Methods

The three methods for proper polarity defined by TIA 568 standard are named as Method A, Method B and Method C. To match these standards, three type of MPO truck cables with different structures named Type A, Type B and Type C are being used for the three different connectivity methods respectively. In this part, the three different cables will be introduced firstly and then the three connectivity methods.

MPO Trunk Cable Type A: Type A cable also known as straight cable, is a straight through cable with a key up MPO connector on one end and a key down MPO connector on the opposite end. This makes the fibers at each end of the cable have the same fiber position. For example, the fiber located at position 1 (P1) of the connector on one side will arrive at P1 at the other connector. The fiber sequence of a 12 fiber MPO Type A cable is showed as the following:

Type A MTP Cable

MPO Trunk Cable Type B: Type B cable (reversed cable) uses key up connector on both ends of the cable. This type of array mating results in an inversion, which means the fiber positions are reversed at each end. The fiber at P1 at one end is mated with fiber at P12 at the opposing end. The following picture shows the fiber sequences of a 12 fiber Type B cable.

Type B cable

MPO Trunk Cable Type C: Type C cable (pairs flipped cable) looks like Type A cable with one key up connector and one key down connector on each side. However, in Type C each adjacent pair of fibers at one end are flipped at the other end. For example, the fiber at position 1 on one end is shifted to position 2 at the other end of the cable. The fiber at position 2 at one end is shifted to position 1 at the opposite end etc. The fiber sequence of Type C cable is demonstrated in the following picture.

Type C Cable

Three Connectivity Methods

Different polarity methods use different types of MTP trunk cables. However, all the methods should use duplex patch cable to achieve the fiber circuit. The TIA standard also defines two types of duplex fiber patch cables terminated with LC or SC connectors to complete an end-to-end fiber duplex connection: A-to-A type patch cable—a cross version and A-to-B type patch cable—a straight-through version.

Duplex patch cable

The following part illustrates how the components in MPO system are used together to maintain the proper polarization connectivity, which are defined by TIA standards.

Method A: the connectivity Method A is shown in the following picture. A type-A trunk cable connects a MPO module on each side of the link. In Method A, two types of patch cords are used to correct the polarity. The patch cable on the left is standard duplex A-to-B type, while on the right a duplex A-to-A type patch cable is employed.

Method A

Method B: in Connectivity Method B, a Type B truck cable is used to connect the two modules on each side of the link. As mentioned, the fiber positions of Type B cable are reversed at each end. Therefore standard A-to-B type duplex patch cables are used on both sided.

Method B

Method C: the pair-reversed trunk cable is used in Method C connectivity to connect the MPO modules one each side of the link. Patch cords at both ends are the standard duplex A-to-B type.

Method C

Conclusion

Network designer using MPO/MTP components to satisfy the increasing requirement for higher transmission speed, during which one of the big problems—polarity, can be solved by selecting the right types of MPO cables, MPO connectors, MPO cassette and patch cables. The three different polarization methods can be applied according to the satisfy requirements in different situations. For more information about polarity in MPO systems and 40/100GbE transmission polarity solutions, please visit Fiberstore tutorial at “Polarity and MPO Technology in 40/100GbE Transmission“.

Related articles: Understanding Polarity in MPO System

                             Introduction to MTP Connector and MPO Connector