Thursday, June 30, 2016

Guide to Fiber Optical Connectors

Fiber optical cable is the composite material, typically consists of a hair-thin glass used to transmit pulses of light instead of electrical signals. Thus the termination must be much more precise. Compared with copper cables end with RJ connectors, fiber optic connectors must align microscopic glass fibers perfectly to make metal to metal contact. There are many different types of fiber connectors, they share similar design characteristics, such as LC to LC patch cord, single mode LC to ST fiber patch cable, single mode fiber ST to SC patch cord, single mode fiber cable with LC connector, etc. Nowadays most cables are ended with the same connector, which poses a problem for users to sort through cables and connectivity options. That’s why this article is provided here to help out the illustration of fiber optics and optical connectors.
Internal Structure of Optical Connector
Fiber optic connector terminates the end of fiber optic cable, enabling quicker connection and disconnection than splicing. As noted before, optical connector has to be aligned properly to the microscopic glass fibers completely in order to allocate for communication. There are three major components of a fiber connector: the ferrule, the connector body, and the coupling mechanism.
  • Ferrule
It is a thin structure that is actually used to holds the glass fiber, which has a hollowed-out center that forms a tight grip on the fiber. Ferrules are usually made from ceramic, metal, or high-quality plastic, and typically will hold one strand of fiber.
  • Connector Body
This is a plastic or metal structure that holds the ferrule and attaches to the jacket and strengthens members of the fiber cable itself.
  • Coupling Mechanism
This is a part of the connector body that holds the connector in place when it gets attached to another device. It may be a latch clip, a bayonet-style nut, or similar device.
Different Types of Fiber Optic Connectors
To sum up, there are nearly 100 fiber optic connectors on the market, but only a few are available that was lower loss, lower cost, easier to terminate. Optical connectors like LC connector, SC connector, ST connector, FC connector, RJ45 connector, MT-RJ connector are the representative that will be present to you.
  • SC Connector
SC or square connector, was developed by Nippon Telegraph and Telephone on the market, slowly grew in popularity as manufacturing cost went down. Now it is becoming increasingly popular in single-mode fiber optic cable, analog CATV, GPON, GBIC. SC is a snap (push-pull coupling) connector with a 2.5mm ferrule diameter that operates on the standard IEC 61754-4. The connector’s outer square profile together with its snap coupling mechanism that allows greater connector packaging density in instruments and patch panels. The SC fiber patch cord is ideally suited for datacoms and telecoms applications including point to point and passive optical networking.

  • LC  Connector
LC or Lucent Connector, is a push-pull, small form factor connector that uses a 1.25mm ferrule, half the size of the SC. Due to the combination of small size and latch feature, LC connector is ideal for high-density connections and usually utilized in SFP, SFP+, XFP, and single-mode QSFP+ transceivers. Along with the development of LC compatible transceivers and active networking components, it will continue to grow in the FTTH arena.

  • FC Connector
FC or Ferrule Connector., is a round, threaded fiber optic connector that was designed by Nippon Telephone and Telegraph in Japan. The FC connector is applied for single-mode fiber and polarization-maintaining optic fiber. The FC is a screw type connector with a 2.5mm ferrule, which was the first fiber optic connector to use a ceramic ferrule. However, FC is becoming less common and gradually replaced by SC and LC connectors because of its vibration loosening and insertion loss.

  • ST Connector
ST or Straight Tip, was developed by AT&T shortly after the arrival of the FC. They may be mistaken for one another, but ST uses a bayonet mount other than a screw thread. And you have to make sure SC connectors are seated properly owing to its spring-loaded structure. SC is mainly used in multimode fiber optic cable, campuses and buildings.

  • RJ-45 Connector
RJ-45 connectors are physically wider than the RJ-11/12 connectors used for telephone. In network applications, RJ-45 cable assemblies are used to connect from a patch panel to a network switch, and also to connect a computer's NIC to a data port.

  • MT-RJ Connector
The MTRJ connector closely resembles an RJ-style modular plug, even getting part of its name from the resemblance. It is covered in the TIA connector intermateability standard FOCIS-12 (TIA-604-12). MT-RJ is a duplex connector with both fibers in a single polymer ferrule. It uses pins for alignment and has male and female versions. Multimode only, field terminated only by prepolished/splice method.

Whether you are about to install a new fiber optic network, or perhaps you are maintaining on an existing one, you are supposed to have a basic knowledge about fiber optics and optical connector. This article simply illustrates the most commonly used fiber optic connectors on the market to help you sort through the optical connectors. But if you’re still not sure which fiber optic connectors are right for you, or perhaps you’d like some more information you can always get in touch with FS.COM.

Tuesday, June 28, 2016

Understand and Tackle Fiber Loss in Fiber Network

Optical fiber is the ideal transmission medium for light signals in contrast to copper cable, and it rarely needs amplification. When the signals carried by light travel through the core of fiber jumper cables, the strength of the light will be weaker, as it’s impossible not to incur degradation of light over the length of the network connection. It is inevitable, but if the signal becomes too weak, it will affect the performance of the fiber optic network. So understanding and tackling these losses is a critical part of network installation and testing.
tackle fiber loss
This loss of light power is generally called fiber optic loss or attenuation (measured in dB). High-quality single-mode fiber will often exhibit attenuation. The cause of fiber optic loss located on two aspects: internal reasons and external causes of fiber optic, which we often use the term insertion loss (IL) and return loss (RL) to describe it.
Insertion Loss
Insertion loss refers to the measurement of light that is lost between two fixed points in the fiber, which usually occurs when optical fibers are spliced together, connected, or sent through additional passive network components. It is often attributed to misalignment, contamination, or poorly manufactured connectors (ferrules) and has long been used to advocate fusion splicing. However, in reality, the attenuation difference between fusion splicing and manual connections is marginal (less than 0.1 dB).
Optical connectors might be most likely the cause of high IL, but it’s unfair to think of them as the only culprit. I have watched a splice engineer perform a perfect fusion splice onto a mass-produced, low-cost commodity pigtail, because the Optical Network Terminal (ONT) called for an SC or LC connector. In reality, we can manage connector losses by stipulating the IL standards of the cables we buy, and training installers to keep things clean. Reducing the number of components within the network also logically lowers the insertion loss.
Furthermore, micro and macro-bending (see in Figure 2) may attribute to significant IL, or cracks to the glass caused by over-tensioning (pulling) or by crush and impact damage. This is often the worst kind of attenuation because it takes time to develop and is much more difficult to pinpoint.
Another reason for fiber seemingly exhibiting high IL in fiber to the home (FTTH) networks is the route of the cable itself. For example, a fiber might travel 10km from the OLT to the curb and lose less than 1dB, and then go on to lose three times as much in the next 100 meters. Multi dwelling units (MDUs) are a great example of complex fiber routes, and it is especially important to protect bend radii, such as with dedicated raceways or microducts. Fiber can quite easily become tightly coiled or kinked during installation; even bend insensitive G657A1 fiber coiled just once to 20mm diameter will see as much as 0.2dB loss. Coiled twice at 20mm 0.4dB, three times and... you get the picture.
Return Loss
Fiber Return loss also have great impacts on the network’s performance (see in Figure 3). It refers to the amount of signal reflected back towards the source due to an impedance mismatch effectively, if this is too high, the laser within the network may stop transmitting correctly. Many systems can cope with 40dB return loss (RL), equivalent to 0.01 per cent of the power being sent back. FTTH, however, is more demanding, and RL cannot be more (lower) than -60dB, sometimes higher.
Cable, specifically, can show high RL if a gap exists (such as fiber undercut) or if the fiber is broken. Contamination, torsion, strain or poorly seated connectors can also lead to high return losses. Therefore, it is important that networks are tested to ensure that there aren’t any unexpectedly high RL figures that indicate problems with equipment or fibers. To achieve these ultra-low RL figures, optical connectors must have angled ferrules (APC).
Insertion loss and return loss are not the same thing and, therefore, need to be measured separately. Measuring the RL on the fiber will pinpoint the issue as the response would be unexpectedly high. The complexity of fiber networks, and the need to measure optical losses, can potentially lead to confusion. However, careful planning, use of high-quality components and a focus on testing will enable installers to deliver high-speed connections that perform well over the long term. Here are five easy tips for reducing your losses.
Tips for Reducing Fiber Loss
1. Minimize tight bends that cause light to refract through the fiber cladding. If you need to coil fiber, keep the radius as large as possible.
2. Clean connector ferrules little and often - especially before and after testing—and always use the right tools and consumables.
3. Decide which is higher: your "power loss" budget or your cable inventory budget. Buying cheap fiber can create larger costs further down the line.
4. Avoid any undue stress on the fiber, particularly during installation. Push where possible and if a cable needs pulling, do not exceed the cable’s maximum tensile load.
5. Minimize the number of splices or connections in your network; if it means better planning or more innovative drop cables, the investment is probably well worth it.
The power or strength of the signal is typically higher at the head end of the optical network, but lower at the other end because of the fiber loss. To ensure smooth fiber optic transmission, fiber optic loss must be decreased. You can follow the above tips to help you out. FS.COM provides a variety of fiber optic patch cables that are well tested for insertion loss for high quality before shipment. For example, LC to SC patch cord is offered. If you have any requirement of our products, please send your request to us.

Thursday, June 23, 2016

Guide to Two 40GBASE-LR4 QSFP+ Links - CWDM and PSM

The common 40GBASE-LR4 QSFP+ optical transceivers that are available on the market are QSFP-40GE-LR4, QSFP-40G-LR4, QSFP-40G-LR4-S and WSP-Q40GLR4L. They are all compatible with 40GBASE-LR4 standard, but differ with each other. Since I have already explained the difference between the above 4 optical transceivers, I will not go further about these topic today. Except for the different 40GBASE-LR4 QSFP+ transceivers types, there are also two links for 40GBASE-LR4 standards. One is coarse wavelength division multiplexing (CWDM). The other is parallel single-mode fiber (PSM). In this article, these two links of 40GBASE-LR4 QSFP+ transceivers will be introduced to you.
40GBASE-LR4 CWDM QSFP+ Transceiver
The 40GBASE-LR4 CWDM QSFP+ transceiver (like QSFP-40GE-LR4) is compliant to IEEE P802.3ba 40GBASE-LR4 standard. This QSFP module supports link lengths of up to 10km over single-mode fiber (SMF) with duplex LC connectors. This transceiver converts 4 inputs channels of 10G electrical data to 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array, and then multiplexes them into a single channel for 40G optical transmission, propagating out of the transmitter module from the SMF. Reversely, the receiver module accepts the 40G CWDM optical signals input, and demultiplexes it into 4 individual 10G channels with different wavelengths. The central wavelengths of the 4 CWDM channels are 1271, 1291, 1311 and 1331 nm (defined as members of the CWDM wavelength grid in ITU-T G694.2). Each wavelength channel is collected by a discrete photo diode and output as electric data after being amplified by a transimpedance amplifier (TIA).
40GBASE-LR4 PSM QSFP+ Transceiver
Unlike CWDM QSFP+ transceiver using a LC connector, PSM QSFP+ is a parallel single-mode optical transceiver with an MTP/MPO fiber ribbon connector. It also offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G on 10km of single-mode fiber. Proper alignment is ensured by the guide pins inside the receptacle. The cable usually cannot be twisted for proper channel to channel alignment. In terms of a PSM QSFP+, the transmitter module accepts electrical input signals compatible with common mode logic (CML) levels. All input data signals are differential and internally terminated. The receiver module converts parallel optical input signals via a photo detector array into parallel electrical output signals. The receiver module outputs electrical signals are also voltage compatible with CML levels. All data signals are differential and support a data rates up to 10.3G per channel.
Compare 40GBASE-LR4 CWDM QSFP+ With 40GBASE-LR4 PSM QSFP+ Transceiver
As noted before, 40GBASE-LR4 CWDM QSFP+ transceivers use a duplex LC connector via 2 optical single-mode fibers to achieve 40G without making any changes to the previous 10G fiber cable plant. However, 40GBASE-LR4 PSM QSFP+ transceivers use an MTP/MPO fiber ribbon connector via 8 optical single-mode fibers to reach 40G. Obviously, CWDM QSFP+ is a more cost-effective solution for 40G connectivity.
What’s more, in terms of the inner structure of an optical transceiver module, PSM QSFP+ uses a single uncooled CW laser that splits its output power into four integrated silicon modulators, which is much inexpensive than CWDM QSFP+. Besides, its array-fiber coupling to an MTP connector is relatively simple. A picture comparing the key differences between CWDM and PSM is shown below:
two links of QSFP+ 40GBASE-LR4
Additionally, the caveat is that the entire optical fiber infrastructure within a data center, including patch panels, has to be changed to accommodate MTP connectors and ribbon cables, which are more expensive than conventional LC connectors and regular SMF cables. Not to mention that cleaning MTP connectors is not a straightforward task.
PSM and CWDM are the two links of 40GBASE-LR4 QSFP+ transceivers. Both of them can support a link distance of 10km. However, 40GBASE-LR4 CWDM QSFP+ are more common than 40GBASE-LR4 PSM QSFP+ because of its performance and low cost. Fiberstore offers a wide brand compatible 40G CWDM QSFP+ transceivers. Each of our fiber optic transceivers has been tested to ensure its compatibility and interoperability. For more information or quotation, please contact us directly.

Thursday, June 16, 2016

How to Reduce the Cost of FTTH Architecture

In our digital world, people increasingly require higher bandwidth to facilitate daily life, whether for leisure, work, education or keeping in contact with friends and family. The presence and speed of internet are regarded as the key factor that subscribers would take into account when buying a new house. Recently there are a growing number of independent companies offering full fiber to the home (FTTH) services, ranging from local cooperatives and community groups to new operators. Today’s article will pay special attention to the reasons why we should implement FTTH network and the methods to reduce the cost of FTTH network.
Why Should We Deploy FTTH Network?
FTTH logo
No denying that the world is changing rapidly and becoming increasingly digital. People nowadays are knowledgeable workers who rely on fast connections to information stored in the cloud to do their jobs. Therefore, installing superfast FTTH broadband is an investment in equipping communities with the infrastructure they need to not just adapt to the present life, but to thrive in the future.
What’s more, the economic benefits of FTTH, for residents, businesses and the wider community are potentially enormous. While there are upfront costs in FTTH deployments, particularly around the last drop, equipment and methodologies are evolving to reduce these significantly. Fiber to the home is proven to increase customer satisfaction, and enables operators to offer new services, such as video on demand, 4K TV and smart home connectivity.
As well as bringing in economic benefits, FTTH broadband provides local businesses with the ability to expand, invest and seek new opportunities by providing rapid connections to major markets. All of this leads to increased investment in the rural economy, providing residents with more choice and stimulating growth.
What to Do?
Although deploying FTTH network might be similar cost as deploying copper network, there are some methods that you should know about reducing the costs of FTTH architecture. Adopting the following three principles helps achieve FTTH deployment, maximizing return on investment and dramatically reducing deployment times.
1. Reuse the Existing Equipment
Time and the total cost of FTTH deployment are typically relevant with the civil engineering side of the project, such as digging a new trench and burying a new duct within it. Where possible, crews should look to reuse existing infrastructure—often there are ducts or routes already in place that can be used for FTTH and in building deployments. These could be carrying other telecommunication cables, power lines, or gas/water/sewerage. Installing within these routes requires careful planning and use of cables and ducts that are small enough to fit through potentially crowded pathways. Figure 2 shows a generic point-multipoint architecture that fiber jumper plays an important part in it.
FTTH architecture
Additionally utilizing the push and pull cables in FTTH infrastructure simply reduce costs and install time as network installers can easily complete FTTH deployment by using pushing or pulling cables: pushing can be aided by simple, cost-effective handheld blowing machines, or pulled through the duct using a pre-attached pull cord. Even for more complex and longer environment, FTTH deployment can be quickly completed other than requiring expensive blowing equipment to propel the cable through duct.
2. Choose the Right Construction Techniques
If it is time to start digging, always make sure you use appropriate construction methods. The appropriate method will minimize cost and time by making construction work as fast and concentrated as possible, avoiding major disruption to customers or the local area. And remember to make sure you follow best practice and use the right fiber cable and duct that can fit into tight spaces and withstand the high temperatures of the sealant used to make roadways good.
FTTH deployment
The cable and duct used within FTTH implementations is crucial. Ensure that it meets the specific needs of deployments, and is tough, reliable and has a bend radius. It should be lightweight to aid installation and small enough to fit into small gaps and spaces in ducts. Also look to speed up installations with pre-connectorized cables that avoid the need to field fit or splice.
3. Minimize the Skills Required
Staff costs are one of the biggest elements of the implementation budget. Additionally, there are shortages of many fiber skills, such as splicing, which can delay the rate at which rollouts are completed. Operators, therefore, need to look at deskilling installations where possible, while increasing productivity and ensuring reliability. Using pre-connectorized fiber is central to this—it doesn’t require splicing and is proven to reduce the skill levels needed within implementations.
To cope with the digital world, the network is in constant need of enhancements and the increasingly stressed bandwidth and performance requires ongoing adjustment. Regardless of the FTTH architecture and the technology to the curb, the pressure is on for the network installer to deploy FTTH quickly and cost-effectively, while still ensuring a high quality, reliable installation that causes minimal disruption to customers and the local area. Fiberstore offers a variety of optical equipment that are suitable in telecom field. Our fiber optic cables are available in different optical connector, single-mode and multimode fiber as well as indoor or outdoor cables. For example, patch cord LC-LC are also provided.

Tuesday, June 14, 2016

Why Is Optical Fiber Key to Cloud Computing?

In such a digital world, human beings are keen on developing technologies to facilitate daily lives. In order to process and store tons of information, many different forms of storage like CD-ROM, USB Key, and DVD has been developed. However, the above devices can only store limited data, which is not adequate for the information explosion. Thus cloud computing, as an advanced storage solution, appears on the stage. So how to achieve cloud computer? Different voices with different opinions emerge, but from a technician’s standpoint, a reliable cabling connectivity or fiber jumper is key to cloud computing. Whether you agree with my opinion or not, the following article will provide some detailed information about it to help you find out the answer.
What Is Cloud Computing?
The “Cloud” in the term cloud computing, describes an image of the complex infrastructure, covering all the technical details. Obviously, the cloud computing has nothing to do with the weather “cloud”. It is just an analogy to give it a body to imagine. Cloud computing is a model for computing transforming. In this model, data and computation are operated somewhere in a “cloud”, which is some collection of data centers owned and maintained by a third party. This enables ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction.
There are public cloud, private public and hybrid cloud. When a cloud is made available in a pay-as-you-go manner to the general public, we call it a public cloud. And when the cloud infrastructure is operated solely for a business or an organization, it is called private cloud. A composition of public and private cloud is called hybrid cloud. A hybrid cloud integrates the advantages of public cloud and private cloud, where private cloud is able to maintain high service availability by scaling up their system with externally provisioned resources from a public cloud when there are rapid workload fluctuations or hardware failures.
Optical Fiber Is the Key to Cloud Computing
In the “cloud” network, subscribers’ terminals are simplified into a pure and single device with only input and output functions but meanwhile utilize the powerful computing and processing functions from the “cloud”. This means that the terminal must have a very fast connection, because the simple terminal means fast network and powerful platform requirement, where “pipes” are put forward higher requirement. Thus, fiber is the ideal “pipe” for cloud computing. The following image shows the evolution of memory storage.
In fact, computer applications, software and even file storage now reside on the Internet or in the “cloud”. Yet another driving force is mobile Internet traffic, which relies heavily on cloud computing. It is said that there is over 1 Exabyte of data currently stored in the cloud. And this number is growing exponentially every day. The greatest thing that will limit your ability to work seamlessly in the “cloud” is your Internet connection. Thus, to access the tremendous amounts data, we need fiber networks that can carry Terabits—one trillion bits per second. Fiber jumper cables can offer more available bandwidth and speed which meets the demands of the “cloud”. Obviously, no technology is more effective at meeting that challenge than fiber at present.
What’s more, FTTH infrastructure is expected as a solution to meet the growing demands for high bandwidth. It brings fiber optic connections directly into homes, allowing for delivery speeds up to a possible 100 Mbps, or even more. These speeds open the door to a variety of new services and applications for residential, business and public service markets. The relationship between FTTH and cloud computing is subtle. FTTH encourages the growth of cloud computing with its benefits. And cloud computing may in turn drives the development of FTTH.
As cloud computing market continues to mature, current and potential information technology capabilities offers many benefits to our lives. However, just like other new technology advancement, cloud computing also faces many challenges, which requires all of us to form thoughts on the strengths and downfalls of the technology. Fiber optic cable, as an indispensable component of network infrastructure, plays a vital role in cloud computing. After going through the whole passage, do you agree with me? Or what’s your opinion? You can leave your messages to share with us.

Wednesday, June 8, 2016

Fiber Types and Corresponding Optical Transceivers

Fiber optic patch cable as the basic element of a network, transmits signals through strands of glass or plastic fiber. Fiber optic cables are available in multimode and single-mode fibers terminated with LC, SC, ST, LC, FC, MTRJ, E2000 connectors in simplex and duplex. The typical multimode fiber used in telecom or datacom applications has a core size of 50 or 62.5 microns. Single-mode fiber shrinks the core size down to 9 microns so that the light can only travel in one ray. Different fiber types like multimode or single-mode fibers connect with fiber optic transceivers resulting in different performances, which makes a huge impact on the network application. Here is what you need to know about the fiber types and the corresponding optical transceivers for network infrastructure.
Internal Structure of Single-mode and Multimode Fiber Optic Cable
An optical fiber is a flexible filament of very clear glass capable of carrying information in the form of light. Single-mode fiber optic cable has a small diametral core of 9/125 microns that allows only one mode of light to propagate, which results in light reflections, lower attenuation and creating the ability for the signal to travel faster, further. That’s why single-mode fibers are typically used in long-reach applications.
internal structure of fiber optic cable
MM fiber patch cords, however, has a large diametral core of 50/125 and 62.5/125 in construction that allows multiple modes of light to propagate. Therefore, 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. Because of the high dispersion and attenuation rate with this type of fiber, the quality of the signal is reduced over long distances. The above picture shows the inner structure of fiber optic cables.
Factors When Choosing Single-mode or Multimode Fiber
Different core diameters of single-mode and multimode fiber optic cables affect the optical properties and have a direct impact on system performance. Besides this, other factors like bandwidth, attenuation and costs also have the biggest impact on the system performance. Figure 2 gives you a vivid description of single-mode and multimode fiber.
single-mode and multimode fiber specification
Attenuation is the reduction of signal power, or loss, as light travels through an optical fiber. Fiber attenuation is measured in decibels per kilometer (dB/km). The higher the attenuation, the higher rate of signal loss of a given fiber length. Single-mode fibers generally operate at 1310 nm (for short range) while multimode fibers operate at 850 nm or 1300 nm. Attenuation is not usually considered to be the main limiting factor in short rang transmissions. But it can cause big differences in high speed network such as 100Gb/s.
Bandwidth means the carrying capacity of fiber. For single-mode fiber, the modal dispersion can be ignored since its small core diameter. Bandwidth behavior of multimode fibers is caused by multi-modal dispersion during the light traveling along different paths in the core of the fiber. It has an influence on the system performance and data rate handling. Multimode fiber uses a graded index profile to minimize modal dispersion. This design maximizes bandwidth while maintaining larger core diameters for simplified assembly, connectivity and low cost. So manufacturers start to develop higher-performance multimode fiber systems with higher bandwidth.
Costs: A fiber optic transceiver usually consists the optical light sources, typically LED–light emitting diode and optical receivers. Since the core diameter size and primary operating wavelengths of single-mode fiber and multimode fiber are different, the associated transceiver technology and connectivity will also be different. So is the system cost.
To utilize the single-mode fibers generally for long distance applications, transceivers with lasers that operate at longer wavelengths with smaller spot-size and narrower spectral width. But these kinds of transceivers need higher precision alignment and tighter connector tolerance to smaller core diameters. Thus, it causes higher costs for single-mode fiber interconnections. To lower the cost, manufacturers produce transceivers based on VCSEL (vertical cavity surface emitting laser), for example, 10G-SFPP-SR is a SFP+ transceiver support a link length of 300m, which are optimized for use with multimode fibers. Transceivers applying low cost VCSEL technology to develop for 50/125μm multimode fibers, take advantage of the larger core diameter to gain high coupling efficiency and wider geometrical tolerances. OM3 and OM4 multimode fibers offer high bandwidth to support data rates from 10Mb/s to 100Gb/s.
Fiber Type and Associated Optical Transceiver Compatibility Matrix
From a technician's standpoint, optical transceivers should be compatible with fiber optic cables, meaning that multimode transceivers should only connect with multimode fiber optic cables, or you may end up with an error. Table 3 summarizes various optical interfaces and their performance over the different fiber types. The table specifies the maximum reach achievable over each fiber type and the requirement for a mode conditioning patch cord.
This table is directly derived from the IEEE 802.3-2005 standard, if you comply with the standard, these performances are guaranteed and longer reaches may be achievable depending on the quality of each link. To ensure whether a link can work, all you can do is to try and see if the performance is satisfactory. The link should be either error-free for critical applications, or the bit error should remain below 10-12 as per minimum standard requirement. For instance, it may be possible to reach much longer distances than 550 m with an OM3 laser-optimized fiber and 1000BASE-SX interfaces. Also, it may be possible to reach 2 km between two 1000BASE-LX devices over any fiber type with mode conditioning path cords properly installed at both ends. Single mode fiber patch cables as noted before, are suitable for long-haul application. Although the optics are more expensive, they’re offering much longer reach, which makes them an ideal choice for network infrastructure.
Choosing the right fiber for your network application is a critical decision. Whether to use single-mode or multimode fiber for your infrastructure, no one can give your the best answer. Only by fully understand the system requirements and select the appropriate fiber can you maximize the value and performance of your cabling system. FS.COM offers cost-effective fiber optic patch cables to meet the requirements of all the customers. If you are interested, please send your request to us.

Monday, June 6, 2016

Loose-Tube or Tight Buffer Indoor/Outdoor Cable for FTTH Application

FTTH (Fiber to the Home) network compared with technologies now used in most places, increases the connection speeds available for residences, apartment building and enterprises. FTTH network is the installation and use of optical fiber from a central point known as an access node to individual buildings. The links between subscriber and access node are achieved by fiber jumper cables. Loose-tube and tight buffer cables are commonly used to transmit signals with high speed, which are capable of supporting outdoor or indoor environment. Is there a cost-effective solution that can support both indoor and outdoor environment in FTTH network? To answer this, the construction and comparison of loose tube cable and tight buffer cable will be introduced in the following article.
Loose-Tube and Tight-Buffer Cable
The “buffer” in tight buffer cable refers to a basic component of fiber optic cable, which is the first layer used to define the type of cable construction. Typically a fiber optic cable consists of the optical fiber, buffer, strength members and an outer protective jacket (as showed in Figure 1). Loose-tube and tight-buffer cables are two basic cable design. Loose-tube cable is used in the majority of outside-plant installations, and tight-buffered cable, primarily used inside buildings.
Loose-tube cable consists of a buffer layer that has an inner diameter much larger than the diameter of the fiber see in the following picture. Thus, the cable will be subject to temperature extremes in the identification and administration of fibers in the system. That’s why loose-tube cables are usually used in outdoor application. The loose-tube 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.
Tight buffer cable using a buffer attached to the fiber coating is generally smaller in diameter than loose buffer cable (showed in Figure 2). 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.
the basic structure of tight buffer cable
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.
Choose Tight Buffer Cable for FTTH Network
The inner construction of tight buffer indoor/outdoor cable have been introduced above. The following will explain why tight buffered indoor/outdoor cable is a better FTTH cabling solution. Figure 3 shows a clear structure of FTTH network.
FTTH network
Using the traditional choice of LTGF cables as the outdoor cable, there would be a conversion from one fiber type to 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.
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.
This article has explained loose-tube and tight buffer indoor/outdoor cables. Network installer can run a single cable type and remove a transition point between the outside plant and the inside plant. At the same time, the reliability of the overall FTTH network can be increased greatly. FS.COM offers high quality fiber cable assemblies such as Patch Cords, Pigtails, MCPs, Breakout Cables etc. All of our custom fiber patch cords can be ordered as Single Mode 9/125, Multimode 62.5/125 OM1, Multimode 50/125 OM2 and Multimode 10 Gig 50/125 OM3/OM4 fibers. If you have any requirement, please send your request to us.