Tag Archives: multimode fiber

Five Basics About Fiber Optic Cables

A fiber optic cable is a network cable that contains strands of glass fibers inside an insulated casing. They’re designed for high performance data networking and telecommunications. Fiber optic cables carry communication signals using pulses of light, faster than copper cabling which uses electricity. They are becoming the most significant communication media in data center. Then how much do you know about them? This post serves as a guide for beginners.

Fiber Components

The three basic elements of a fiber optic cable are the core, cladding and coating. Core is the light transmission area of the fiber, either glass or plastic. The larger the core, the more light that will be transmitted into the fiber. The function of the cladding is to provide a lower refractive index at the core interface, causing reflection within the core. Therefore the light waves can be transmitted through the fiber. Coatings are usually multi-layers of plastics applied to preserve fiber strength, absorb shock and provide extra fiber protection.

Fiber Components

Fiber Type

Generally, there are two basic types of fiber optic cables: single mode fiber (SMF) and multimode fiber (MMF). Furthermore, multimode fiber cores may be either step index or graded index.

Single mode and multi-mode fiber-optic cables

Single mode optical fiber is a single strand of glass fiber with a diameter of 8.3 to 10 microns that has one mode of transmission. The index of refraction between the core and the cladding changes less than it does for multimode fibers. Light thus travels parallel to the axis, creating little pulse dispersion. It’s often used for long-distance signal transmission.

Step index multimode fiber has a large core, up to 100 microns in diameter. As a result, some of the light rays that make up the digital pulse may travel a direct route, whereas others zigzag as they bounce off the cladding. These alternative pathways cause the different groupings of light rays to arrive separately at a receiving point. Consequently, this type of fiber is best suited for transmission over short distances.

Graded index fibers are commercially available with core diameters of 50, 62.5 and 100 microns. It contains a core in which the refractive index diminishes gradually from the center axis out toward the cladding. The higher refractive index at the center makes the light rays moving down the axis advance more slowly than those near the cladding.

Fiber Size

Single mode fibers usually has a 9 micron core and a 125 micron cladding (9/125µm). Multimode fibers originally came in several sizes, optimized for various networks and sources, but the data industry standardized on 62.5 core fiber in the mid-80s (62.5/125 fiber has a 62.5 micron core and a 125 micron cladding. It’s now called OM1). Recently, as gigabit and 10 gigabit networks have become widely used, an old fiber design has been upgraded. 50/125 fiber was used from the late 70s with lasers for telecom applications. 50/125 fiber (OM2) offers higher bandwidth with the laser sources used in the gigabit LANs and can allow gigabit links to go longer distances. Laser-optimized 50/125 fiber (OM3 or OM4) today is considered by most to be the best choice for multimode applications.

Basic Cable Design

The two basic cable designs are loose-tube cable, used in the majority of outside plant installations, and tight-buffered cable, primarily used inside buildings.

loose-tube-or-tight-buffered-cable

The modular design of loose-tube cables typically holds up to 12 fibers per buffer tube with a maximum per cable fiber count of more than 200 fibers. Loose-tube cables can be all dielectric or optionally armored. The modular buffer-tube design permits easy drop-off of groups of fibers at intermediate points, without interfering with other protected buffer tubes being routed to other locations.

Tight-buffered cables can be divided into single fiber tight-buffered cables and multi-fiber tight-buffered cables. single fiber tight-buffered cables are used as pigtails, patch cords and jumpers to terminate loose-tube cables directly into opto-electronic transmitters, receivers and other active and passive components. While multi-fiber tight-buffered cables also are available and are used primarily for alternative routing and handling flexibility and ease within buildings.

Connector Type

While there are many different types of fiber connectors, they share similar design characteristics. Simplex vs. duplex: Simplex means 1 connector per end while duplex means 2 connectors per end. The following picture shows various connector styles as well as characteristics.

fiber cable connectors

Summary

Ultimately, what we’ve discussed is only the tip of the iceberg. If you are eager to know more about the fiber optic cable, either basics, applications or purchasing, please visit www.fs.com for more information.

10GBASE-LRM vs. 10GBASE-LX4, Which One Wins?

For 10 Gigabit data transmission, various physical-layer interconnects are available, such as 10GBASE-LX4, CX4, SR, LR and ER as well as 10GBASE-LRM. With so many options, you may be confused which one is the best. This article will discuss two options requiring for multimode fiber cable. They are standards LX4 and LRM. Which one do you think is better?

10GBASE-LX4

Now maybe 10GBASE-LX4 is not so popular. But it’s not the same case several years ago. This standard is the first optical interface standard developed to run at 10 Gbits/sec over multimode optical fiber backbones in vertical risers. LX4 was robust and stable. Many vendors have produced LX4 related equipment. Once there was an industry trade group—the LX4-TG (LX4 Trade Group) formed to promote LX4 technology.

10G-LX4

Later, the LRM standard is developed by the same IEEE group that generated the LX4 standard. The specifications can only support the distance of 220 m. At first, technicians intended to stretch the coverage to be 300 m. However, it’s too risky and limited the ability to release the standard in a timely manner. The reduced distance is good for more robust LRM operation, but may limit the product’s applications in some building backbones.

10G-LRM

Performance of 10GBASE-LX4 and LRM

10g lrm and lx4

LX4 module can be used for both single-mode or multimode fiber connection with distance up to 10 km and 300 m. LX4 applies CWDM technology using four wavelength—transmitters near 1300 nm, a CWDM multiplexer and demultiplexer, and four receivers. The advantage of this approach is that the transmitters and receivers are all operating at about one-quarter of the data rate; so the data transmission is robust to modal dispersion. But it has the disadvantages of high cost, big size and non-manufacturability.

While LRM uses wavelength of 1310 nm with a single transmitter and a receiver with an adaptive electronic equalizer IC in the receive chain. LRM module has a simpler optical path. The laser of LRM module can be a distributed-feedback (DFB) laser, a vertical-cavity surface-emitting laser (VCSEL), or a Fabry-Perot (FP) laser. Both DFBs and VCSELs provide a very clean, single-wavelength output, which minimizes signal degradation due to spectral effects. And an FP laser source can produce a range of different wavelengths. Different wavelengths travel through the fiber at slightly different speeds, creating additional jitter which will be recovered by the EDC known as adaptive equalization technology. EDC is used to compensate for the differential modal dispersion (DMD) present in legacy fiber channels.

Advantages of LRM

The LRM approach has three key advantages over LX4. The following will give an introduction from three sides.

Size — LX4 uses four lasers and laser drivers and four photodiodes and preamplifiers, which makes LX4 module a big size. But LRM uses the same optical component footprint as other 10G modules, with EDC functionality.

Cost — LRM devices cost less than LX4 equipment. From the point of manufacturing yields and packaging and assembly cost, the price of LX4 is higher than that of other short reach 10G modules. By contrast, LRM substitutes low-cost silicon for the optical complexity of LX4. So it greatly reduces the cost.

Assembly — LX4 requires a significant amount of assembly (splicing, fiber attach and routing, and in some cases multiple personal computer boards, flex cables, etc.). Thus it naturally reduces yields at the module level and makes the module difficult to be manufactured. However, LRM requires no extra assembly compared with existing 10G SR or LR modules.

Conclusion

LX4, as the first standard developed for 10GBASE data rate over multimode fiber backbones, has its special significance in the fiber optic communication history. As technology is continuously developing, so better objects will be created and replace the not so good ones. LRM is another standard for 10GBASE. It turns to be more popular with its smaller size, lower cost and greater manufacturability. So 10GBASE-LRM SFP is a good choice for your 10GBASE network. FS.COM offers Brocade 10G-SFP-LRM compatible 10GBASE-LRM SFP 1310nm 220m DOM transceivers and other 10G SFP modules. Each transceiver has been tested on full range of Brocade equipment to keep 100% compatibility. Any service, please contact via sales@fs.com.

Optical Fiber Selection for Network Interconnection

The emergence of Data Centers, Storage Area Networks and other computing applications drives the needs for ultra-high speed data interconnections and structured cabling. The interconnect media choices include wireless technology, copper cable and optical fiber cable. Fiber cable offers the highest bandwidth and supports the highest data rates. There are single-mode and multimode fiber types. Different types of fiber connect with fiber optic transceivers resulting in different performances and costs. So it’s important for the network designers to understand the fiber types and select the right fiber and corresponding fiber optic transceivers for network interconnection.

Optical Fiber Types

There are three main types of optical fiber suitable for network interconnection use:
9/125μm Single-mode fiber
50/125μm multimode fiber
62.5/125μm multimode fiber

optical-fiber-types

The above numbers respectively mean the diameter of the glass core where the light travels and outside glass cladding diameter which is almost the same to most fiber types. So the difference of each fiber type is caused by the core diameter. It has great impact on system performance and system cost when balanced against network application needs. Two primary affected factors are attenuation and bandwidth.

Factors Affected by the Fiber Core Diameter

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.

System Costs: Single-mode and Multimode Fibers

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 (multi-kilometer reach), transceivers with lasers such as SFPP-10GE-LR (an SFP+ 1310nm 10 km transceiver supporting single-mode fibers) 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 (an SFP+ 850nm 300m transceiver supporting multimode fibers), 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.

Conclusion

Optical fiber is an easily-installed medium that is immune to electromagnetic interface and is also more efficient in terms of power consumption. What’s more, fiber optic cable can save space and cost with higher cabling density and port density over copper cabling. For single-mode fiber and multimode fiber, each one has its advantages and disadvantages. Network designers should better select the right fiber type and related fiber optic transceivers according to specific situations for higher system performance. Of course, cost is another important factor to be considered.

WBMMF – Next Generation Duplex Multimode Fiber in the Data Center

Enterprise data center and cloud operators use multimode fiber for most of their deployments because it offers the lowest cost means of transporting high data rates for distances aligned with the needs of these environments. The connections typically run at 10G over a duplex multimode fiber pair—one transmit (Tx) fiber and one receive (Rx) fiber. Upgrading to 40G and 100G using MMF has traditionally required the use of parallel ribbons of fiber. While parallel transmission is simple and effective, continuation of this trend drives higher cost into the cabling system. However, a new generation of multimode fiber called WBMMF (wideband multimode fiber) is on the way, which can enable transmission of 40G or 100G over a single pair of fibers rather than the four or ten pairs used today. Now, let’s get close to WBMMF.

What Is Wideband Multimode Fiber?
WBMMF is a new multimode fiber type under development that will extend the ability of conventional OM4 multimode fiber to support multiple wavelengths. Unlike traditional multimode fiber, which supports transmission at the single wavelength of 850 nm, WBMMF will support traffic over a range of wavelengths from 850 to 950 nm. This capability will enable multiple lanes of traffic over the same strand of fiber to transmit 40G and 100G over a single pair of fibers and to drastically increase the capacity of parallel-fiber infrastructure, opening the door to 4-pair 400GE and terabit applications. Multimode fiber continues to provide the most cost-effective platform for high bandwidth connectivity in the data center, and with the launch of the WBMMF solution, that platform has been extended to support higher speeds with fewer fibers and at greater distances.

Wideband Multimode Fiber

What Is the Technology Behind WBMMF?
WBMMF uses short wavelength division multiplexing (SWDM) to significantly increase its transmission capacity by four times. WDM technology is well known for its use in single-mode transmission, but has only recently been adapted for use with vertical cavity surface-emitting lasers (VCSELs), which have been proven in high-speed optical communications and are widely deployed in 10G interconnection applications. SWDM multiplexes different wavelengths onto duplex MMF utilizing WDM VCSEL technology. By simultaneously transmitting four VCSELs, each operating at a slightly different wavelength, a single pair WBMMF can reliably transfer 40G (4x10G) or 100G (4x25G). The use of SWDM then enables WBMMF to maintain the cost advantage of multimode fiber systems over single-mode fiber in short links and greatly increases the total link capacity in a multimode fiber link.

SWDM WBMMF

Why Does WBMMF Make Sense?
In order to increase transmission speeds up to 10G or 25G, transceiver vendors simply increased the speed of their devices. When 40G and 100G standards were developed, transmission schemes that used parallel fibers were introduced. This increase in fiber count provided a simple solution to limitations of the technology available at the time. It was accepted in the industry and allowed multimode links to maintain a low cost advantage. However, the fiber count increase was not without issues. At some point, simply increasing the number of fibers for each new speed became unreasonable, in part because the cable management of parallel fiber solutions, combined with the increasing number of links in a data center, becomes very challenging. Please see the picture below. Usually, 40G is implemented using eight of the twelve fibers in an MPO connector. Four of these eight fibers are used to transmit while the other four are used to receive. Each Tx/Rx pair is operating at 10G. But if we use WDMMF, two fibers are enough. Each Tx/Rx pair can transmit 40G by simultaneously transmitting four different wavelengths. This enables at least a four-fold reduction in the number of fibers for a given data rate, which provides a cost-effective cabling solution for data center.

Parallel fibers vs WBMMF

Conclusion
WBMMF is born at the right moment to meet the challenges associated with escalating data rates and the ongoing need to build cost-effective infrastructure. Besides, WBMMF will support existing OM4 applications to the same link distance. Optimized to support wavelengths in the 850 nm to 950 nm range to take advantage of SWDM, WBMMF ensures not only more efficient support for future applications to useful distances, but also complete compatibility with legacy applications, making it an ideal universal medium that supports not only the applications of the present, but also those of the future.

Original article source: http://www.cables-solutions.com/wbmmf-next-generation-duplex-multimode-fiber-in-the-data-center.html

Link Budget Evaluation Over SMF and MMF

Evaluating a link budget is equivalent to calculating the total loss suffered by a transmitted signal along fiber channels with the minimum receiver power to maintain normal operation. Calculating the link budget helps network architects to identify the feasibility of a physical-layer deployment.

Optical fibers come in several different configurations, each ideally suited to a different use or application. Early fiber designs that are still used today include single-mode fiber (SMF) and multimode fiber (MMF). And the most common optical communication data links include point-to-point transmission, WDM and amplified transmission. This article depicts the rules to be applied in order to evaluate link budget of these optical transmissions over SMF and MMF.

Link Budget for Point-to-Point Transmissions over Multimode Fibers

In this first case, the rule is fairly simple. A few parameters need to be taken into account:
● The minimum transmit power guaranteed (minTx), expressed in dBm
● The minimum receive power required (minRx), expressed in dBm
● The loss of optical connectors and adapters (L), expressed in dB
● The number of connectors and adapters (n)
● The normalized fiber loss (FL), expressed in dB/km
● The reach or distance to be achieved (d), expressed in km
With these parameters, the link budget (LB) expressed in dB is given as follows:
● (LB) = (minTx) – (minRx)
This value needs to be compared to the total loss (TL) suffered by the transmitted signal along the given link, and expressed in dB:
● (TL) = n*(L) + d*(FL)
If LB is greater than TL, then the physical deployment is theoretically possible.
In these calculations n is at least equal to 2 since there are a minimum of 2 connectors at each end, L is typically around 0.5 to 1 dB, and FL is of about 1 to 1.5 dB per km.

Link Budget for Point-to-Point Transmissions over Single-mode Fibers

At first, you need to know that the lasers deployed in optical communications typically operate at or around 850 nm (first window), 1310 nm (second window), and 1550 nm (third and fourth windows). In this second case, the calculations are exactly similar to the previous case. Only the numerical values will differ. For single-mode point-to-point transmissions, n is at least equal to 2, L is typically around 0.3 to 0.5 dB, and FL is of about 0.4 dB per km in the second window and about 0.25 dB per km in the third window.

The following drawings show the power budget of a 2km hybrid multimode/singlemode link with 5 connections (2 connectors at each end and 3 connections at patch panels in the link) and one splice in the middle.

power budget

Link Budget for WDM and Amplified Transmissions over Single-mode Fibers

In the case of WDM transmissions, passive modules are used to multiplex and demultiplex various wavelengths respectively before and after the signal propagates along the fiber channel. These passive modules introduce additional insertion losses suffered by the signal transmitted.

Additionally, the signal may be amplified and compensated for dispersion, and in this case, the amplifier gain and the dispersion compensation unit’s loss need to be taken into account. Dispersion and OSNR (optical signal noise ratio) penalties suffered by the receiver shall be considered as well.

Therefore all the parameters needed for a proper link budget evaluation are:
● The minimum transmit power guaranteed (minTx), expressed in dB/m
● The minimum receive power required (minRx), expressed in dB/m
● The loss of optical connectors and adapters (L), expressed in dB
● The number of connectors and adapters (n)
● The normalized fiber loss (FL), expressed in dB/km
● The reach or distance to be achieved (d), expressed in km
● The loss of passive add/drop modules (A and D), expressed in dB
● The gain of the amplifier (G), expressed in dB
● The penalty suffered by the receiver (P), expressed in dB
● The loss of a dispersion compensation unit (DCU), expressed in dB With these parameters, (LB) is given as for previous cases:
● (LB) = (minTx) – (minRx)
And the total loss is expressed as follows:
● (TL) = n*(L) + d*(FL) + (A) + (D) – (G) + (DCU) + (P)
Here again, if LB is greater than TL, then the physical deployment is feasible. Please note that for simplicity, only one amplifier, one dispersion compensation unit, and one set of add/drop modules are considered in this example. If more devices are planned to be deployed, their loss or gain should be added or subtracted accordingly in order to calculate TL.

Link budget is a way of quantifying the link performance. And the performance of any communication link depends on the quality of the equipment being used. Thus, when evaluating a link budget, you are supposed to consider the types of applications, the reach to be achieved, as well as the types of optical fibers deployed. For more information about fiber optical link products, please visit FS.COM.

Understanding Wavelengths in Fiber Optics

The light we are most familiar with is surely the light we can see. Our eyes are sensitive to light whose wavelength is in the range of about 400 nm to 700 nm, from the violet to the red. But for fiber optics with glass fibers, we use light in the infrared region which has wavelengths longer than visible light. Because the attenuation of the fiber is less at longer wavelengths. This text may mainly tell you what the common wavelengths used in fiber optics are and why they are used.

wavelength-nm

Wavelengths Definition

In fact, light is defined by its wavelength. It is a member of the frequency spectrum, and each frequency (sometimes also called color) of light has a wavelength associated with it. Wavelength and frequency are related. Generally, the radiation of shorter wavelengths are identified by their wavelengths, while the longer wavelengths are identified by their frequency.

Common Wavelengths in Fiber Optics

Wavelengths typically range from 800 nm to 1600 nm, but by far the most common wavelengths actually used in fiber optics are 850 nm, 1300 nm, and 1550 nm. Multimode fiber is designed to operate at 850 nm and 1300 nm, while single-mode fiber is optimized for 1310 nm and 1550 nm. The difference between 1300 nm and 1310 nm is simply a matter of convention. Both lasers and LEDs are used to transmit light through optical fiber. Lasers are usually used for 1310nm or 1550nm single-mode applications. LEDs are used for 850nm or 1300nm multimode applications.

wavelength-nm

Why Those Common Wavelengths?

As mentioned above, the most common wavelengths used in fiber optics are 850 nm, 1300 nm and 1550 nm. But why do we use these three wavelengths? Because the attenuation of the fiber is much less at those wavelengths. Therefore, they best match the transmission properties of available light sources with the transmission qualities of optical fiber. The attenuation of glass optical fiber is caused by two factors: absorption and scattering. Absorption occurs in several specific wavelengths called water bands due to the absorption by minute amounts of water vapor in the glass. Scattering is caused by light bouncing off atoms or molecules in the glass.

It is strongly a function of wavelength, with longer wavelengths having much lower scattering. From the chart below, we can obviously see that there are three low-lying areas of absorption, and an ever-decreasing amount of scattering as wavelengths increase. As you can see, all three popular wavelengths have almost zero absorption.

wavelength-nm

Conclusion

After reading this passage, you may know some basic knowledge of wavelengths in fiber optics. Since the attenuation of the wavelengths at 850 nm, 1300 nm, and 1550 nm are relatively less, they are the most three common wavelengths used in fiber optic communication. Fiberstore offer all kinds multimode and single-mode fiber optic transceivers which operate on 850 nm and 1310 nm respectively very well. For more information, please visit fs.com.

Do You Know About Mode Conditioning Patch Cord?

The great demand for increased bandwidth has prompted the release of the 802.3z standard (IEEE) for Gigabit Ethernet over optical fiber. As we all know, 1000BASE-LX transceiver modules can only operate on single-mode fibers. However, this may pose a problem if an existing fiber network utilizes multimode fibers. When a single-mode fiber is launched into a multimode fiber, a phenomenon known as Differential Mode Delay (DMD) will appear. This effect can cause multiple signals to be generated which may confuse the receiver and produce errors. To solve this problem, a mode conditioning patch cord is needed. In this article, some knowledge of mode conditioning patch cords will be introduced.

What Is a Mode Conditioning Patch Cord?

A mode conditioning patch cord is a duplex multimode cord that has a small length of single-mode fiber at the start of the transmission length. The basic principle behind the cord is that you launch your laser into the small section of single-mode fiber, then the other end of the single-mode fiber is coupled to multimode section of the cable with the core offset from the center of the multimode fiber (see diagram below).

mode conditioning patch cord

This offset point creates a launch that is similar to typical multimode LED launches. By using an offset between the single-mode fiber and the multimode fiber, mode conditioning patch cords eliminate DMD and the resulting multiple signals allowing use of 1000BASE-LX over existing multimode fiber cable systems. Therefore, these mode conditioning patch cords allow customers an upgrade of their hardware technology without the costly upgrade of their fiber plant.

Some Tips When Using Mode Conditioning Patch Cord

After learning about some knowledge of mode conditioning patch cords, but do you know how to use it? Then some tips when using mode conditioning cables will be presented.

    • Mode conditioning patch cords are usually used in pairs. Which means that you will need a mode conditioning patch cord at each end to connect the equipment to the cable plant. So these patch cords are usually ordered in numbers. You may see someone only order one patch cord, then it is usually because they keep it as a spare.
    • If your 1000BASE-LX transceiver module is equipped with SC or LC connectors, please be sure to connect the yellow leg (single-mode) of the cable to the transmit side, and the orange leg (multimode) to the receive side of the equipment. The swap of transmit and receive can only be done at the cable plant side. See diagram below.

mode conditioning patch cord

  • Mode conditioning patch cords can only convert single-mode to multimode. If you want to convert multimode to single-mode, then a media converter will be required.
  • Besides, mode conditioning patch cables are used in the 1300nm or 1310nm optical wavelength window, and should not be used for 850nm short wavelength window such as 1000Base-SX.

Conclusion

From the text, we know that mode conditioning patch cords really significantly improve the data signal quality and increase the transmission distance. But when using it, there are also some tips must be kept in mind. Fiberstore offer mode conditioning patch cords in all varieties and combinations of SC, ST, MT-RJ and LC fiber optic connectors. All of the Fiberstore’s mode conditioning patch cords are at high quality and low price. For more information, please visit fs.com.

What Is Single Mode Fiber?

It is obvious that the fiber-optics are steadily replacing copper wire in telecommunications. The main difference between fiber optic systems and copper wire systems is how they transmit information. Fiber optic cable transmit signals by using light pulses instead of electronic pluses. The light pulses enable fiber optic cable to transmit more data with further distance and fewer signal loss. So fiber optical cables are now widely used for television services, university campuses, office buildings or other long-distance applications. Here will depict one kind of optical fiber: single mode fiber.

Introduction to Single Mode Fiber

Single mode fiber is one kind of fiber which is a single stand of glass fiber deigned to carry light only directly down the transverse mode. Its core diameter is 8.3 to 10 microns. Compared to multimode fiber whose diameter is 50 to 100 microns, single mode fiber has a smaller core, which allows fewer signals to be transmitted simultaneously on a fiber. So the light can only travel on a single path not multimode patch. With only one mode of transmission, single mode fiber has no intermodal dispersion. Multimode fiber transmit signals through multimode paths for its larger core. Those multimode fiber can cause signal distortion at the receiving end in long-distance transmission, making signals unclear and incomplete. In addition, the index of refraction between the core and cladding of single mode changes less than it does for multimode fiber, creating little dispersion.

fiber_mode

Conditions for Launching Light to Single Mode Fiber

As one type of optical fiber, single mode fiber carry lights to transmit information. But what should we take care of when launching light into single mode fiber?

Efficiently launching light into a single mode fiber requires the transverse complex amplitude profile of that light at the fiber’s input ends matches that of the guided mode. This means the light source have a high beam quality and a focus at the fiber’s input end and the light should be precisely aligned. A light into a single mode fiber needs well designed mechanical conditions. Taking lasers for example, the laser beam should has the correct size, allowing to precisely align and keep the fixed the focusing lens. It is usually easy to align correctly at the target position, but angular alignment is more critical.

Applications of Single Mode Fiber

Single mode fiber can achieve a high beam quality of the output together with WDM technology and optical amplifiers. In the optical links, single mode fiber can be used to connect different components such as connectors by fusion splicing. Due to little signal dispersion, single mode fiber is widely used for long-distance transmission. Optical media converters are used to do the fiber to fiber conversion to connect two different transmission modes, making single mode fiber efficient in long-distance transmission.

LC-LC Single-mode Fiber Patch Cable

For more information about single mode fiber cable, please visit WWW.FS.COM. Various single mode fiber solutions for you to choose.

What Are OM1, OM2, OM3 and OM4?

Multimode fiber is a kind of optical cables which is designed to carry multimode light rays or modes concurrently. Those light rays or modes are reflected at slightly different angles within the optical core which is in the standard 125-μm cladding. And due to its modes tend to disperse over long distance, multimode fiber is applied for communications over short distances. Now there are four types of mulimode fibers: OM1, OM2, OM3 and OM4 types which are of different properties. This article will introduce the four types in details.

OM1 Fiber

OM1 fiber has a core size of 62.5µm with an orange jacket which is at the wavelength of 850 nm /1300 nm. It supports 10 Gigabit Ethernet at lengths up 33 meters but is most commonly used for 100 Megabit Ethernet applications. In the 80’s, 90’s and early 2000’s, the 62.5/125µm OM1 fiber was thought to be the most popular multimode fiber choice for it has the lowest data carrying capacity and shortest distance limitations in comparison with other multimode fiber types.

Multimoder FIber Core Diameters

OM2 Fiber

OM2 fiber commonly comes with an orange jacket but has a core size of 50µm instead of 62.5µm. It also typically operates at 850 nm/1300 nm. It supports 10 Gigabit Ethernet at lengths up to 82 meters but is more commonly used for 1 Gigabit Ethernet applications. The 50/125µm OM2 multimode fiber was first invented by Corning in the 1970s and gradually became popular and even the first choice for newly established networks for it supports longer transmission distance and higher bandwidth.

Note: OM1and OM2 fiber are both orange jacket fiber and work well with LED based equipment.

OM3 Fiber

OM3 fiber is 50µm core diameter with aqua jacket. Optimized for lased based equipment which needs fewer mode of light, it is capable of being applied in 10 Gigabit Ethernet at strengths up to 300 meters. The 50/125 µm OM3 fiber is considered to be the best choice for 10 Gigabit Ethernet unless you need the extra distance provided by OM4. Enhancements on its inception and production technologies enable OM3 to be used in 40 Gigabit and 100 Gigabit Ethernet at lengths up to 100 meters.

OM4 Fiber

OM4 fiber has the same core size and jacket color as OM3 fiber. It is also optimized for laser based equipment. As a further development of OM3 fiber, it can support 10 Gigabit Ethernet at lengths up 550 meters and 100G Gigabit Ethernet at lengths up 150 meters. Now as the rapid development of 40G and 100G Gigabit Ethernet, OM4 fiber is widely applied especially in data centers. It provides the most cost effective solutions for data centers by avoiding the higher costs associated with single-mode laser source.OM1 Fiber and OM4 Fiber

For more information, please visit Fiberstore

Multimode Fiber Patch Cables from Fiberstore

Fiberstore has been providing quality fiber optical cabling and connectivity solutions to datacomm and telecommunication industries to worldwide customers for over ten years. As a specialized fiber optic cables and patch cables manufacturer, we have conducted rigorous quality controls on each manufacture steps, to make sure that all of our fiber optic cables are completely ROHS and REACH compliant. Our fiber optic patch cables are classified to common multimode fiber cables (OM1, OM2, OM3, OM4 patch cables), armored fiber patch cables, related fiber cables, MTP/MPO trunk cables, multi-core fiber patch cables as well as many other fiber patch cables. This article is set up to mainly introduce the multi-core fiber patch cords.

Multi-core fiber patch cable get its name as it is consist of multi core fiber, which also called multimode fiber patch cable. Multi fiber patch cable is most commonly used for trunk cable plant and can be as the distribution or breakout patch cable. We offer the fiber trunk patch cables with SC, LC, FC, ST, MTRJ, MU, E2000 connectors, 2-288 cores/fibers are optional to be customized and the sub-branch can be 0.9 mm and 2.0 mm.

12-fiber-mtp-om4-patch-cable

For each connector type, like LC, there are LC to FC, LC to SC, LC to ST, LC to MTRJ, LC to MU, LC to E2000, LC to SMA and LC to LC fiber cable, all of which are optically and electrically inspected and tested using accepted industry test procedures as recommended by the most current version of ANSI/TIA-455B standard test procedure for standard fiber optic fiber, cables, transducers, sensors, connecting & terminating devices, and other components.

The multi fiber patch cables features include:

  • Multi-fiber channel options
  • Various option of fiber and connector types
  • Standard or custom configurations
  • Easy to use, easy to install and maintain
  • Low insertion loss and back reflection
  • Custom defined specifications
  • Environmentally stable
  • Complete with orange OFNR rated riser/jacket
  • 100% optically tested to ensure high performance
  • According to different requirements, 4 to 966 cores are available

Applications:

  • FTTH, LAN, Test equipment, Military industry
  • CATV
  • Outside plant
  • Premise networks
  • Aerial distribution
  • Measuring equipment
  • Fiber optic communication system
  • Optical active component and equipment

We offer custom service for customers with options of any fiber type, any connectors, and lengths and even customer logo and label on fiber patch cables. Fiber types is selectable from 10G OM3, OM4 optical fiber, single mode 9/125 optical fiber, OM1, OM2 multimode 50/125 fibers.