Overview of Active Optical Cable

In respond to the demand for a higher data bandwidth, active optical cable (AOC) has came into being to satisfy different cloud computing applications. Active optical cable is a term used to describe a cable that mates with standard electrical interfaces. The electrical-to-optical conversion on the cable ends is adopted to enhance the transmission speed and distance of the cable without sacrificing compatibility of standard electrical interfaces. This article will give a general introduction of active optical cable and its most popular product in the current market.

Structure of Active Optical Cable

Active optical cable mainly consists of two parts- the fiber optic connector and fiber cable. The connection between fiber cable and connectors is not separable. If the connector or cable needs to be changed, they should be removed together. The electrical and optical signal conversion can be achieved right through each ends of optical fiber.

Advantages of Active Optical Cable

However, people may wonder the reasons why choosing active optical cable over direct attach copper cable. Here are some advantages of using active optical cable:

1) Although both cables are used for short range data communication, active optical cable is able to provide a longer reach than direct attach copper cable among devices.

2) Active optical cable has a higher bandwidth because its signal transmits through optical fiber as optical signal which transmits faster than electrical signal in copper cable. The maximum throughput is up to 40 Gbps with QSFP+.

3) The weight of active optical cable is lighter than copper cable due to the optical fiber material. It is possible to achieve a simpler cable management with a lower weight.

4) EMI (electromagnetic interference) immunity is another benefit of active optical fiber. EMI is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling or conduction. Since the optical fiber is a kind of dielectric which is unable to conduct electric current, active optical cable will not be affected by the electromagnetic energy.

Applications of Active Optical Cable

Active optical cable has been applied to different fields. The followings are the most typical applications for active optical cables:

1) Infiniband QDR, DDR and SDR interconnects

2) Data aggregation, backplane and proprietary density applications

3) PCI-Express, SAS/SATA, Fiber Channel compatible interconnect

4) 40GBE and 10GBE interconnects

5) 10G, 40G telecom connections

6) Hubs, switches, routers, servers

7) Ethernet 10G, 40G

8) Data centers

9) High performance computing clusters

Popularity of 40G Active Optical Cable

Nowadays 40G active optical cable has become one of the most popular products in the market. It is an active optical cable used for 40 GbE terminated with 40GBASE QSFP+. Particularly, 40G breakout active optical cables, such as 40GBASE QSFP+ to 4xSFP+ AOC or 40GBASE QSFP+ to 8xLC AOC, are cost-effective solutions for 40G to 10G migration.

Conclusion

Active optical cable has now taken a great share of the market and is still booming for further development. The interconnection in short range and high speed between devices makes it practical in data center. As the technology matures, the application of active optical cable will be migrated to higher speed transmission in the future.

The article originates from http://www.chinacablesbuy.com/overview-of-active-optical-cable.html.

Introduction of Fiber Splice Tray

Fiber splice tray is designed to provide a place to store the fiber cables and splices and prevent them from becoming damaged or being misplaced. It is also called as splice enclosure or splice organizer. This device does not contain any technical functions, and the design is simple. Also, it has a very low price for people to afford. However, the importance of fiber splice tray for protecting fibers is significant. And the skills needed for using fiber splice tray is not as simple as you think.

Function of Fiber Splice Tray

With such a simple structure, you may wonder how the fiber splice tray actually works. Here is the brief introduction of its working function: The incoming cable is brought into the splicing center where the outside jacket of the cable is stripped away. The fibers are then looped completely around the tray and into a splice holder. Different holders are available for different types of splices. The fibers are then spliced onto the outgoing cable if it is an intermediate point or on to pigtails if it is a termination point. These are also looped completely around the tray and then fed out of the tray.

Installation Procedures

The installation procedures can be divided into five steps:

Step one, route fibers into splice tray using spiral transportation or fiber furcation tubes and secure with cable ties.

Step two, splice fibers per local practice.

Step three, place spliced fibers into the sleeve holders arranged by color code.

Step four, carefully coil the outgoing fiber slack into the tray (coil 1).

Step five, carefully coil incoming fiber slack into the tray (coil 2).

Applications

Fiber splice trays are usually placed in the middle of a route where cables are required to be joined or at the termination and patch panel points at the end of the cable runs. Also, splices can be placed in a splice tray which is then placed inside a splice closure for OSP (outside plant) installations or a patch panel box for premises applications. As for indoor application, fiber splice trays are often integrated into patch panels to provide for connections to the fibers.

Conclusion

As a protection for fiber splices, fiber splice tray is no doubt the most cost-effective device. This simple design solves a lot of problems during fiber cables installation. Fiberstore provides different shaped splice trays with different fiber capacities in a competitive price. If you are interested, FS.COM is a good place to go.

The article originates from http://www.fiber-optical-networking.com/introduction-of-fiber-splice-tray.html.

Guide to Fusion Splicer Selection

Optic fiber is now widely applied to networks around the globe. When it comes to actual operation, connecting fibers is a necessary task. And fusion splicer is an effective tool for fiber optic splicing. But choosing the right type of fusion splicer is still a challenge. In this article, we will talk about how to find the most matching fusion splicer.

Before discussing about different types of fusion splicer, let’s first have a look at the working principle and specific function of a fusion splicer. The fusion splicer is the device that uses heat to melt the ends of two optic fibers and combines them together into one fiber. By using the fusion splicer, the joint is permanent so that light signals can pass from one fiber to another with little link loss. The heating source of a fusion splicer can be a laser, a gas flame, a tungsten filament or a electric arc. And the most popular heating source at present is electric arc.

Nowadays, there are two types of fusion splicer according to different aligning systems. One is called the core alignment fusion splicer, the other is cladding alignment fusion splicer. If you can figure out the differences between these two types of fusion splicer, finding a right fusion splicer is no longer a problem.

Core Alignment Fusion Splicer

Core alignment is the most welcome fusion splicing technology at present. The splicer combines the image and light detection systems which can view the fibers cores in order to measure and monitor core position. Fiber cores are put in V-grooves and are aligned horizontally (X-axis), vertically (Y-axis) and in/out (Z-axis). The type of fusion splicer is adaptable for all kinds of fibers, such as single-mode or multimode fiber, good or bad fiber and splicing old fiber to new fiber. It is much more expensive but provides a more precised alignment.

Cladding Alignment Fusion Splicer

Cladding alignment is also called as passive alignment or fixed V-groove type. This type of fusion splicer relies on the accurate pre-alignment of fiber V-grooves that grip the outer surface or cladding of the fiber. Fiber cores are adjusted inwards and outwards. This type of fusion splicer is only available for multimode fiber or good single-mode fibers. As to cladding alignment fusion splicer, the cost is lower and alignment is faster, but its demand for the quality of fiber is higher or else will cause a lot of losses.

Suggestions For Fiber Optic Splicing

Though the two types of fiber optic splicing are different, the methods for better splicing are common. Here are some suggestions for fiber optic splicing:

1. Clean the fusion splicer before splicing. Any invisible contamination will cause tremendous problems when splicing the fibers.

2. In order to increase the alignment speed for fusion splicer, it is important to maintain and operate other tools, such fiber cleaver. A good cleaving will save time for splicing and decrease fiber loss.

3. Make sure the fusion parameters are adjusted minimally and methodically. The changes of parameters will also generate problems for your desired setting.

Conclusion

Selecting a suitable fusion splicer is beneficial to the splicing process. You may consider your needs and affordable cost to find the right fusion splicer. Core alignment fusion splicer has a better performance but a higher price than cladding alignment fusion splicer. Please choose your ideal fusion splicer wisely and do not forget to follow the normative operation for your splicing.

The article originates from http://www.fiber-optic-cable-sale.com/guide-to-fusion-splicer-selection.html.

Introduction to Fiber Optic Splicing

During the actual operation of fiber cables, fiber optic splicing is often needed to achieve the connection between optic fibers. To be specific, fiber optic splicing is a process to combine the ends of optic fibers together. And only one end of each individual fiber is required. There are mainly two types splicing methods: the mechanical splicing and the fusion splicing. The article will introduce these two splicing methods and their particular steps of splicing.

What Is Mechanical Splicing?

Mechanical splicing is using the alignment devices to hold two fiber ends in a precisely aligned position. This enables the light to pass freely through one fiber to another fiber. In this method, the joint is not permanent. Two fibers can still be split after the signal transmission. Mechanical splicing has a low initial investment but costs more for each splice.

What Is Fusion Splicing?

Fusion splicing is using the professional machine to joint two optical fibers ends together. The splicing machine will hold the fibers to align them in a precised position, then using heat or electric arc to fuse or weld glass ends together. This enables the permanent connection between two optic fibers for a continuous light transmission. Fusion splicing needs a much higher initial investment but costs less for each splice than mechanical splicing. In addition, this method is more precised than mechanical splicing, which produces lower loss and less back reflection due to the seamless fusion splice points.

Four Steps of Mechanical Splicing:

1. You need to prepare the fiber by peeling off the outer coatings, jackets, tubes, etc. to just expose the bare fiber. And you much keep the cleanliness of fiber in case of failing the later transmission.

2. You need to cleave the fiber.

3. You need to joint the fibers mechanically with no heat. Just connecting the ends of fiber together inside the mechanical splice unit and the device will help couple the light between two fibers.

4. You need to protect the fiber during the light transmission. Typically, the completed mechanical has its own protection for the splice.

Four Steps of Fusion Splicing:

1. The same as mechanical splicing, you need to strip the outer materials to show the bare fiber. And cleanliness is also required as an important preparation.

2. You need to cleave the fiber. A much more precised cleave is essential to the fusion splice. The cleaved end must be smooth and perpendicular to the fiber axis for a proper splice.

3. You need to splice the fiber with heat. Manual or automatic alignment can be chosen according to the device you are using. A more accurate splice can be achieved if you use a more expensive equipment. Once properly align the fusion splicer unit then you can use an electrical arc to melt the fibers, and permanently weld the two fiber ends together.

4. You need to protect the fiber from bending and tensile forces. By adopting the heat shrink tubing, silicone gel and mechanical crimp protectors can prevent the fiber from breakage.

Conclusion

Fiber optic splicing is important for fiber connections. Two different methods of mechanical splicing and fusion splicing are usually used for splicing. In order to complete the splicing process, many professional tools are required. For example, fiber optic cleavers is deployed for the cleaving step. Fusion splicers is deployed for the fusion splicing method to connect the fibers and optical fiber aligners is deployed for the alignment to enable the light transmission. Fiberstore provides all the above equipment. For more information, please visit the official website at FS.COM.

The article originates from http://www.chinacablesbuy.com/introduction-to-fiber-optic-splicing.html.

What is FTTx Network?

Since the customers have demanded for a more intensive bandwidth, the telecommunication carriers must seek to offer a matured network convergence and enable the revolution of consumer media device interaction. Hence, the emergence of FTTx technology is significant for people all over the world. FTTx, also called as fiber to the x, is a collective term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications. With different network destinations, FTTx can be categorized into several terminologies, such as FTTH, FTTN, FTTC, FTTB, FTTP, etc. The following parts will introduce the above terms at length.

FTTH

FTTx is commonly associated with residential FTTH (fiber to the home) services, and FTTH is certainly one of the fastest growing applications worldwide. In an FTTH deployment, optical cabling terminates at the boundary of the living space so as to reach the individual home and business office where families and officers can both utilize the network in an easier way.

FTTN

In a FTTN (fiber to the node) deployment, the optical fiber terminates in a cabinet which may be as much as a few miles from the customer premises. And the final connection from street cabinet to customer premises usually uses copper. FTTN is often an interim step toward full FTTH and is typically used to deliver advanced triple-play telecommunications services.

FTTC

In a FTTC (fiber to the curb) deployment, optical cabling usually terminates within 300 yards of the customer premises. Fiber cables are installed or utilized along the roadside from the central office to home or office. Using the FTTC technique, the last connection between the curb and home or office can use the coaxial cable. It replaces the old telephone service and enables the different communication services through a single line.

FTTB

In a FTTB (fiber to the building) deployment, optical cabling terminates at the buildings. Unlike FTTH which runs the fiber inside the subscriber’s apartment unit, FTTB only reaches the apartment building’s electrical room. The signal is conveyed to the final distance using any non-optical means, including twisted pair, coaxial cable, wireless, or power line communication. FTTB applies the dedicated access, thus the client can conveniently enjoy the 24-hour high speed Internet by installing a network card on the computer.

FTTP

FTTP (fiber to the premise) is a North American term used to include both FTTH and FTTB deployments. Optical fiber is used for an optical distribution network from the central office all the way to the premises occupied by the subscriber. Since the optical fiber cable can provide a higher bandwidth than copper cable over the last kilometer, operators usually use FTTP to provide voice, video and data services.

FTTx Network Applications

With its high bandwidth potential, FTTx has been closely coupled with triple play of voice, video and data services. And the world has now evolved beyond triple play to a converged multi-play services environment with a high bandwidth requirement. Applications like IPTV, VOIP, RF video, interactive online gaming, security, Internet web hosting, traditional Internet and even smart grid or smart home are widely used in FTTx network.

Conclusion

FTTx technology plays an important part in providing higher bandwidth for global networks. According to different network architectures, FTTx is divided into FTTH, FTTN, FTTC, FTTB, FTTP, etc. FS.COM provides FTTx solutions and tutorials for your project, please visit FS.COM for more information.

The article originates from http://www.fiber-optic-cable-sale.com/what-is-fttx-network.html.

Things You Should Know Before Transceiver Selection

Fiber optic transceiver is an indispensable component for fiber optical transmission. With the popularization of Ethernet networks, there is an increasing demand for transceiver modules in the market. However, when it comes to transceiver selection, you may be confused about whether you have chosen the matching transceiver. Don’t worry, this article will introduce some essential issues for you to consider before buying the product.

Transmission Distance

According to the length of transmission distance, transceivers are varied for either long range or short range. This leads to a decision between single-mode or multimode transceiver. Single-mode transceiver is used for long reach transmission and multimode transceiver for short reach. Typically, if the reach is under 1 km, multimode transceiver is more suitable for the application. And for longer distance, single-mode transceiver is the better choice.

Data Rate

In telecommunication, data signaling rate, also known as gross bit rate, is the aggregate rate at which data pass a point in the transmission path of a data transmission system. It is clear to see the transmission speed through data rate. Commonly used data rates are 100 Mbps, 1 Gbps, 10 Gbps, 40 Gbps and 100 Gbps. The choices for optical transceivers can range from the small form-factor pluggable (SFP) module at 1 Gbps up to the CFP transceiver at 100 Gbps.

Transmission Media

There are two types of transmission media for data communication. One is the copper and the other is optic fiber. Transceivers can used on different media due to different requirements. For instance, in the Gigabit Ethernet, 1000BASE-T SFP can operate on standard Category 5 copper wiring. And 1000BASE-LX can operate on single-mode or multimode fiber.

Compatibility

Although transceivers are designed by a multi-vendor consortium with open specifications, it is usually preferable to match your SFP to your switch vendor. Therefore, compatible transceivers are created to support products from different brands. Make sure you pick up the right transceiver that can link to your device, otherwise the transmission may be failed. By the way, you can buy these compatible transceivers from third party dealers with a relatively lower price. For example, FS.COM might be a good online shopping website where you can buy cost-effective compatible transceivers.

Cost

The cost limit will definitely affect the quality of transceiver you purchase. Typically, single-mode transceiver costs higher than the multimode. And transceivers with higher data rate cost much more than the low speed transceivers. Also, using fibers is more expensive than using coppers. But if your device doesn’t require much about the performance of transceivers, choosing a low-cost transceiver can save you a few bucks.

Conclusion

By considering different specifications of transceivers, such as distance, data rate, media, compatibility, cost, etc., choosing a suitable transceiver is really not an easy task. All the aspects much be properly evaluated to specify the right one for your project. But after your careful selection, I’m sure you will be satisfied with your transceiver.

The article originates from http://www.sfp-transceiver-modules.com/wiki/a/107/Things-You-Should-Know-Before-Transceiver-Selection.

How Much Do You Know About OTDR?

OTDR is short for optical time-domain reflectometer. It has gone through three stages of development. The first stage was in the 1980s. Optical fibers were just put into the market on a large scale. At that time, people still used the original way of fiber testing, and hand-held OTDR device or OTDR inspection technique were adopted to detect optical communication network. The second stage was from the late 1980s to the late 1990s. Fiber optics detection technology has been evolved to achieve real-time monitoring of optical network. The third stage is from the late 20th century to the early 21st century. OTDR has been combined with WDM (wavelength-division multiplexing) based on the advanced optical signal processing technology and all-optical communication devices.

To be specific, OTDR is an optoelectronic instrument used to characterize an optical fiber. It locates defects and faults, and determines the amount of signal loss at any point in an optical fiber. By injecting a series of optical pulses into the fiber, the light that is scattered or reflected will be back from points along the fiber at the same end. The scattered or reflected light that is gathered back is used to characterize the optical fiber. The strength of the return pulses is measured and integrated as a function of time, and plotted as a function of fiber length.

If you want to learn something about OTDR, these specifications are important for you to know:

Dynamic Range

The dynamic range of an OTDR determines the length of a fiber to be measured. The test pulse needs to be strong enough to get to the end of the fiber, and the sensor has to be good enough to measure the weakest backscatter signals which come from the end of a long fiber. Therefore, the pulse power of laser source and the sensitivity of sensor combine to decide whether the dynamic range is large or small. Sufficient dynamic range will produce a clear and smooth indication of the backscatter level at the far end of the fiber.

Dead Zone

Dead zone refers to the space on a fiber trace following a Fresnel reflection in which the high return level of the reflection covers up the lower level of backscatter. It is significant in determining the OTDR’s ability of detecting and measuring two closely spaced events on fiber links. Dead zone occurs in a fiber trace wherever there is a fiber connector. The space is directly related to the pulse width of the laser source. And high quality sensors recover quicker than cheaper ones to achieve shorter dead zones.

Resolution

OTDR includes two resolutions. One is loss resolution and the other is spatial resolution. Loss resolution is the ability of the sensor to distinguish the power levels it receives. Spatial resolution is how close the individual data points that make up a trace are spaced in time and corresponding distance.

Loss Accuracy

Loss accuracy of the OTDR sensor is measured in the same way as optical power meters and photodetectors. The accuracy depends on how closely the electrical current output corresponds to the input optical power.

Distance Accuracy

Clock stability, data point spacing and index of refraction (IOR) uncertainty are three components that may affect distance accuracy. Clock accuracy is stated as a percentage, which relates to percentage of distance measured. If the clock runs too fast or too slow, then the time measurements will be shorter or longer than the actual value. Also, if data point spacing is closer, data points are likely to fall closer to a fault in the fiber. Moreover, IOR is the ratio of the speed of light in a vacuum to the speed of light in a particular fiber. It is critical in accurate measurement of distance. If the IOR is wrong, then the distance will be wrong.

Applications

OTDR has been applied to various aspects of a fiber system. It is typically used to measure overall loss for system acceptance and commissioning, incoming inspection and verification of specifications on fiber reels. As for installation, construction and restoration, OTDR is deployed to measure splice loss in fusion and mechanical splices. When it comes to CATV, SONET and other analog or high-speed digital systems where reflections must be kept down, OTDR is used to measure reflectance or optical return loss of connectors and mechanical splices. Apart from these, it can also be applied to locate fiber breaks and defects, and detects the gradual or sudden degradation of fibers.

Conclusion

In other words, OTDR is a fiber optic tester for the characterization of optical networks that support telecommunications. It is applied to detect, locate, and measure elements at any location on a fiber optic link. And specifications like dynamic range, dead zone, resolution, loss and distance accuracy will influence the OTDR testing results. Thus, you should think twice before selecting an OTDR. Applications of what the instrument will be used for and the specifications of a suitable OTDR must be taken into consideration.

The article originates from http://www.chinacablesbuy.com/how-much-do-you-know-about-otdr.html.

Introduction to Fiber Optic Adapter

A small equipment used for connecting optical fiber cables together is often called as fiber optic adapter or fiber optic coupler. Although they may shape differently, they have the same function. A fiber optic adapter allows fiber optic cables to be attached to each other singly or in a large network, permitting many devices to communicate at once. According to different shapes and structures, fiber optic adapters can be classified in several types, such as FC fiber optic adapter, SC fiber optic adapter, ST fiber optic adapter, LC fiber optic adapter and so on. And this article will particularly introduce these four kinds of fiber optic adapters.

FC Fiber Optic Adapter

FC fiber optic adapter uses a metal sleeve to strengthen its outer structure and can be fastened by a turnbuckle. It also adopts the ceramic pins as its butt end. Therefore, FC fiber optic adapter is able to sustain a stable optical and mechanical performance for a long time. It can be divided into square type, oval type and round type in single-mode and multimode versions. FC fiber optic adapter is easy to operate but sensitive to dust, so it has been enhanced today by using spherical butt end without changing its external structure.

SC Fiber Optic Adapter

Covered with a rectangular shell, SC fiber optic adapter has the same configuration and size of the coupling pin cover as FC fiber optic adapter. From its structures, SC fiber optic adapter can be classified into simplex standard, duplex standard and shuttered standard. From its materials, metal and plastic are commonly used for SC fiber optic adapter. SC fiber optic adapter enables a high precision alignment with a low insertion, return loss and back reflection.

ST Fiber Optic Adapter

ST fiber optic adapter has a key snap-lock structure to ensure accuracy when connecting the cables together. The repeatability and durability of ST fiber optic adapter is improved by the metal key. With a precised ceramic or copper cover, ST fiber optic adapter can also keep a high optical and mechanical performance for a long time. It has two standards of simplex and duplex and uses the metal or plastic housing.

LC Fiber Optic Adapter

LC fiber optic adapter adopts the modular jack latch mechanism which is easy to operate. Using the smaller pins and sleeves, LC fiber optic adapter greatly increases the density of fiber optic connector. There are three types of LC fiber optic adapter in simplex, duplex and quad structures.

Applicable End Faces

Different fiber optic adapters supports different ends faces. PC (physical contact), UPC (ultra physical contact) and APC (angle physical contact) are the polish style used for fiber optic adapters. ST fiber optic adapter is only available with PC and UPC styles. But except ST, the rest three fiber optic adapters support all the polish styles. Moreover, the color of fiber optic adapters can be used to define different end faces of PC, UPC and APC. For example, as for SC and LC fiber optic adapters, there are cream, blue and green colors which correspond to PC, UPC and APC end faces.

Application

In order to help the signal transmission, fiber optic adapter is widely used for telecommunications system, cable TV network, LAN (local area network), WAN (wide area network), FTTH (fiber to the home), video transmission and instrument testing. It is no doubt that fiber optic adapter is of great help for network communications.

Conclusion

Fiber optic adapter provides convenience for fiber cable connections. FC, SC, ST, LC fiber optic adapters are parts of the adapter family and are widely adopted in practical use. Small device like fiber optic adapter really helps a lot for different applications in life, because it greatly improves the working efficiency.

The article originates from http://www.fiber-optic-cable-sale.com/introduction-to-fiber-optic-adapter.html.

Comparison of OM1, OM2, OM3 & OM4

Multimode and single-mode optical fiber cables are two different cable types in optical networking. Using a larger core size, multimode fiber cable allows multiple light signals to be transmitted in a single fiber over short distances. Multimode fiber systems offer flexible, reliable and cost effective cabling solutions for local area networks (LANs), storage area networks (SANs), central offices and data centers. Unlike the complex classifications of single-mode fiber, multimode fiber is usually divided into four types of OM1, OM2, OM3, OM4. “OM” is abbreviated for optical multimode, and it is specified by the ISO/IEC 11801 international standard. Of course, these four types of multimode fiber have different specifications (as shown in the following table). The article will compare these four kinds of fibers from the side of core size, bandwidth, data rate, distance, color and optical source in details.

Core Size

Multimode fiber is provided with the core diameter from 50 µm to 100 µm. Apart from OM1 with a core size of 62.5 µm, other three types are all using the 50 µm. The thick core size makes them able to carry different light waves along numerous paths without modal dispersion limitation. Nevertheless, in the long cable distance, multiple paths of light can cause signal distortion at the receiving end, resulting in an unclear and incomplete data transmission. And this is why all the types of multimode fiber can only be used for short distance.

Bandwidth

Bandwidth is the bit-rate of available or consumed information capacity expressed typically in metric multiples of bits per second. The higher bandwidth is, the faster transmission speed can be. According to overfilled launch (OFL) and effective modal bandwidth (EMB) measurements, OM1 and OM2 can only support OFL, but OM3 and OM4 are able to support both measurements. At the wavelengths of 850/1300 nm under OFL, the respective bandwidth of OM1, OM2, OM3, OM4 is 200/500 MHz*km, 500/500 MHz*km, 1500/500 MHz*km and 3500/500 MHz*km. And at the wavelength of 850 nm under EMB, the bandwidth of OM3 is 2000 MHz*km and OM4 even reaches 4700 MHz*km.

Data Rate

Data rate is a technical term that describes how quickly information can be exchanged between electronic devices. With a higher data rate, the transmission can be more effective. OM1 and OM2 support the Ethernet standards from 100BASE to 10GBASE with a minimum data rate of 100 Mbps and a maximum data rate of 10 Gbps. Compare with OM1 and OM2, OM3 and OM4 are enhanced to support much higher data rates of 40 Gbps and 100Gbps in 40G and 100G Ethernet.

Distance

Multimode fiber is typically used for short distance transmission. But the maximum reaches are varied in different multimode fiber types. Also, on account of different data rates, the transmitting distances are different. However, the common feature is that OM1 always supports the shortest distance yet OM4 supports the longest. For instance, based on the same data rate of 10 Gbps, the maximum reach of OM1 is 33 m, OM2 is 82 m, OM3 is 300 m and OM4 is 550 m. Thus, if a medium-sized transmission is required, OM3 and OM4 are the best choices.

Color & Optical Source

The outer jacket can also be a method to distinguish OM1, OM2 from OM3, OM4. The common jacket color of OM1 and OM2 is orange, and OM3, OM4 are in aqua. In addition, OM1 and OM2 are using a light-emitting diodes (LEDs) optical source but OM3 and OM4 adopt the vertical-cavity surface-emitting laser (VCSELs) optical source.

Application

OM1 and OM2 are widely employed for short-haul networks, local area networks (LANs) and private networks. OM3 is applied to a larger private networks. Different from the previous multimode types, OM4 is more advanced to be used for high-speed networks in data centers, financial centers and corporate campuses.

Conclusion

It is very important to choose the right fiber type for your application. Future-proofing network design is crucial for network planning, but there is often a cost for that speed. With a higher performance, OM3 and OM4 are definitely more expensive than OM1 and OM2. So plan well and spend wisely.

The article originates from http://www.chinacablesbuy.com/comparison-of-om1om2om3-om4.html.

Commonly Used SFP Transceivers

In fiber optic networking, an optical transceiver is a device which can both transmit or receive light and electrical signals. Generally, it has two ports. One is the transmitting port used for converting electrical signal into light signal and the other is the receiving port used for changing light signal into electrical signal. According to different data rates, there are many different kinds of transceivers, such as small form-factor pluggable (SFP), small form-factor pluggable plus (SFP+), quad small form-factor pluggable plus (QSFP+), centum form-factor pluggable (CFP), etc. And this article is going to give a brief introduction to some commonly used SFP transceivers. SFP transceiver, known as small form-factor pluggable transceiver, is a compact and hot-pluggable transceiver used for both telecommunication and data communication applications. It is widely deployed for the Fast Ethernet and Gigabit Ethernet.

Here are some commonly used SFP transceivers:

BiDi SFP

BiDi SFP is short for Bi-Directional SFP. The core technology of this transceiver is the BiDi technique which enables bidirectional transmission of two different waves. Since the BiDi module has only one port , it must be deployed in pairs. For example, when one module is used for receiving 1310nm and transmitting 1550nm optical signals, the other should receive 1550nm and transmit 1310nm signals, and vice versa. In this way, BiDi transceivers usually cost twice the price of other transceivers, but it is a better way to use BiDi transceivers to save the expenditure spent on optical fiber. Because BiDi transceivers have the advantage of reducing fiber cabling infrastructure costs by lowering the number of fiber patch panel ports, decreasing the amount of tray space dedicated to fiber management, and using less fiber cable.

CWDM SFP

CWDM SFP is a kind of single-mode transceiver used for Gigabit Ethernet and Fibre Channel applications. It is made up of three parts: an uncooled laser transmitter, a PIN photodiode integrated with a trans-impedance preamplifier and a MCU control unit. The technology of this transceiver is called coarse wavelength-division multiplexing (CWDM). It is an economical technique to save fiber resources through transmitting multiple wavelengths on one optic fiber. The wavelengths of CWDM SFP are between 1470nm and 1610nm distinguished by different colors. Most commonly used CWDM SFP transceivers include CWDM SFP 1470, CWDM SFP 1490, CWDM SFP 1510, CWDM SFP 1530, CWDM SFP 1550, CWDM SFP 1570, CWDM SFP 1590, CWDM SFP 1610, etc. CWDM SFP can support the high performance of 1.25Gbps data rate and 80km distance of signal transmission.

DWDM SFP

Dense wavelength division multiplexing (DWDM) SFP is the hot-pluggable transceiver used for Gigabit Ethernet which gathers different wavelengths onto one single fiber. Compared with CWDM SFP, DWDM SFP has a more intensive wave spacing for a high performance of data communication. The working wavelength ranges from 1525 nm to 1565 nm or 1570 nm to 1610 nm. The wave intervals are varied in 0.4 nm, 0.8 nm, 1.6 nm, etc. And the port of this transceiver is using the SFP interface for over 1 gigabit optical data transmission.

SONET/SDH SFP

Synchronous optical networking (SONET) SFP or synchronous digital hierarchy (SDH) SFP is a kind of transceiver based on the SONET/SDH standard. SONET/SDH is the physical standard for fiber optical transmission, first brought out by Bellcore in 1980s and then standardized by American National Standards Institute (ANSI) for popularization all over the world. In the SONET/SDH standard, it mainly stipulates the transmission rate, fiber interface, operation and maintenance in optical fiber transmission. The SONET/SDH SFP transceivers can support OC-3 (up to 155.52 Mbps), OC-12 (up to 622.08 Mbps), and OC-48 (up to 2488.32 Mbps) data rates for multimode, short-reach, intermediate-reach, and long-reach applications. With the help of SONET/SDH technique, optical devices around the world are available to connect with each other which greatly improve the efficiency of data communication.

FC SFP

Fibre Channel (FC) SFP is a kind of transceiver using the technology of fiber channel for high speed optical signal transmission with a data rate up to 4.25 Gbps. Fiber channel is a mature technology for serial interface standardized by American National Standards Institute (ANSI). It is applied to the connection between the storage controller and computer drivers. Nowadays, FC has played as a replacement for the Small Computer System Interface (SCSI) in high-performance storage systems, because fiber channel is faster in transmission speed and more flexible in the transmitting mode with or without fiber in accordance with the transmission range.

Application

SFP sockets are found in Ethernet switches, routers, firewalls and network interface cards. In addition, storage interface cards, also called as HBAs or Fibre Channel storage switches, use the SFP modules to support different speeds such as 2Gb, 4Gb, and 8Gb. Because of the low cost, low profile, and ability to provide a connection to different types of optical fiber, SFP provides the related equipment with enhanced flexibility.

Conclusion

SFP transceivers are hot-pluggable small form factors used for 100BASE and 1000BASE Ethernet data transmission. There are different types of SFP modules, including BiDi SFP, CWDM SFP, DWDM SFP, SONET/SDH SFP and FC SFP. Each of them supports different techniques which bring convenience to data communication. FS.COM provides all the SFP transceivers mentioned above, the products will definitely meet your requirements.

The article originates from http://www.sfp-transceiver-modules.com/wiki/a/106/Commonly-Used-SFP-Transceivers.

Overview of Single-mode Fiber Types

According to the light transmission mode, optic fibers can be classified into single-mode and multimode. It’s easy to categorize multimode fiber into four types of OM1, OM2, OM3 and OM4. However, when it comes to single-mode, it may not be as simple as you think. The classification of single-mode fiber is much more complicated than multimode fiber. ITU-T G.65x series and IEC 60793-2-50 (published as BS EN 60793-2-50) are two primary sources for single-mode fiber specification. This article will mainly focus on the ITU-T G.65x series.

The following table introduces 19 ITU-T specifications of 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	TU-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

Each type 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 to the present day. Choosing the right one for your project can be vital in terms of performance, cost, reliability and safety. Now, let’s have a look at the differences of G.65x series specifications for single-mode fiber respectively.

G.652

The ITU-T G.652 fiber is 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 1310nm band. They can also operate in the 1550nm 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 a Dense Wavelength Division Multiplexed (CWDM) system with zero chromatic dispersion, causing unacceptable crosstalk and interference between channels.

G.654

The G.654 specifications entitled “characteristics of a cut-off shifted single-mode optical fiber and cable”. It uses a larger core size made from pure silica to achieve the same long-haul performance with low attenuation in the 1550nm 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 1550nm 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 allows the easier deployment of CWDM in metropolitan areas, and increases 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.

Conclusion

There are different types of single-mode fiber used for different application. G.657 and G.652 are typically favored by planners and installers, and G.657 is particularly deployed for FTTH applications because of a larger bend radius. And G.655 has been taken the place of G.643 used for WDM system. In addition, G.654 is usually applied to the subsea area. To know more information about single-mode fiber, you are welcome to visit the website at FS.COM.

The article originates from http://www.fiber-optic-cable-sale.com/overview-of-single-mode-fiber-types.html.

Who is the Winner of 10G Transceivers?

10G transceivers refer to the optical modules which can transmit and receive the data signal of 10 gigabits per second. Typically, the fiber optic transceivers including XENPAK, X2, XFP and SFP+ (small form-factor pluggable plus) are widely used for 10 Gigabit Ethernet. But who is the winner among these transceivers? From the following introduction we may find some clues.

XENPAK Transceivers

The first published form-factor, the XENPAK, was by far the largest in physical size. This standard was driven primarily by large systems vendors and was intended to support essentially any optical application a system vendor may want to deploy. At the time this multi-source agreement (MSA) was published, 10Gbps optical interfaces supporting transmission distances of 80km or more were of a size and heat dissipation that required a relatively large (by today’s standards) package size.

X2 and XFP Transceivers

Many in the industry recognized the size of the XENPAK as very limiting factor and began working on alternative standards. Over the following two years three alternative MSAs were published, called: X2 and XFP. When these standards were written they were intended to enable optical interfaces supporting up to about 10 km. The X2 and XFP form-factors both saw considerable deployment. As optical technology has advanced over the last ten years, X2 and XFP modules have been developed that support all of the high-power, long-distance applications once reserved to the larger XENPAK transceivers.

SFP+ Transceivers

Five years after the first 10Gbps optical transceiver standard was issued, a new MSA was published called the “SFP+”. This agreement has been the basis for the most commercially successful 10Gbps optical transceivers by a large margin.

There are several reasons for the success of the SFP+ standard:

• Flexibility  The SFP+ standard builds on a previous one, the SFP MSA (primarily a 1Gbps standard). SFP+ modules are the same physical size as SFPs and the SFP+ standard allows for either type of module to operate in the new SFP+ slots.
• Small Size  SFP+ modules are one tenth the size of the original XENPAK 10G modules and are the same size as the popular 1Gbps SFP modules. This small size allows the design of systems with 10G ports of the same density as previous generations with 1G ports.
• Low Cost  Since SFP+ modules share many components (bezel, housing, latch/locking mechanism) on the previous SFP standard, the cost of the new 10G modules inherits the low cost of these components. SFP+ units are also lower power, contributing to cost savings

However, do you really know how to choose the right 10G form-factor? The following aspects should be taken into consideration:

Cost

When considering new or used equipment for a new network build or expansion, attention should definitely be given to the type of 10G ports in that equipment. One important reason is capital costs. Older gear offering XFP, X2 or XENPAK ports may be attractive due to what seems like very low prices. However, the cost of equivalent 10G optics in those older form factors is twice to three times the price of SFP+ based modules. Therefore, when the cost of the optics are included, total system costs may end up higher.

Power

The older XFP, X2 and especially XENPAK gear, both the host system and the 10GBase optical modules, consume considerably more power than the new SFP+ modules. Power costs include capital outlays for larger power/battery plant as well as operational cost of the electrical power itself.

Rack Space

Depending on the location, space in equipment racks can be quite expensive. Equipment utilizing the older 10Gbase interfaces is almost always substantially less dense, consuming more rack space per 10G interface available.

Conclusion

From the above, there is no doubt that SFP+ wins the battle. In consideration of the advantages in cost, size, power and flexibility of supportable optical interfaces, SFP+ is preferred among the 10G transceivers. So far, there has not been any new standard for 10G network due to a higher speed demand of Ethernet. Thus, SFP+ transceivers will remain to dominate the 10G transceiver market.

The article origiantes from http://www.chinacablesbuy.com/who-is-the-winner-of-10g-transceivers.html.