Common Types Of Fiber Optic Cables And Patch Cables

1.FTTH Fiber Optic Cable

 

FTTH (Fiber To The Home), as its name suggests it is a fiber optic directly to the home. Specifically, FTTH refers to the optical network unit (ONU) mounted on home users or business users, is the optical access network application type of closest to users in optical access series except FTTD(fiber to the desktop).

 

There are 5 main advantages of FTTH:

 

First, it is a passive network, from the end to the user, the intermediate can be basically passive;

 

Second, the bandwidth is relatively wide, long distance fits the massive use of operators;

 

Third, because it is carried business in the fiber, and there is no problem;

 

Fourth, because of its relatively wide bandwidth, supported protocol is more flexible;

 

Fifth, with the development of technology, including point-to-point, 1.25G and FTTH have established relatively perfect function

 

2. Indoor Fiber Optic Cable

 

Indoor optical cable is classified according to the using environment, as opposed to outdoor fiber optic cable.

 

Indoor optical cable is a cable composed of fiber optic (optical transmission medium) after a certain process. Mainly by the optical fiber (glass fiber is as thin as hair),plastic protective tube and plastic sheath. There is no gold, silver, copper and aluminum and other metal, fiber optic cable generally has no recycling value.

 

Indoor fiber optic cable is a certain amount of fiber optic forming to cable core according to a certain way, outsourcing jacket, and some also coated layer of protection, to achieve a communication line of light signal transmission.

 

Indoor cable is small tensile strength, poor protective layer, but also more convenient and cheaper. Indoor cable mainly used in building wiring, and connections between network devices.

 

3. Outdoor Fiber Optic Cable

Outdoor fiber optic cable, used for outdoor environment, the opposite of indoor cable.

 

Outdoor cable is a type of communication line to achieve light signal transmission, is composed of a certain amount of fiber optic forming to cable core according to a certain way, outsourcing jacket, and some also coated with outer protective layer.

 

Multimode Fiber Optic Loopback Cable

 

Outdoor cable is mainly consists of optical fiber (glass fiber is as thin as hair), plastic protection tube and plastic sheath. There is no gold, silver, copper and aluminum and other metal cable, generally no recycling value.

 

Outdoor cable is greater tensile strength, thick protective layer, and usually armored(wrapped in metal). Outdoor cables are mainly applied to buildings, and remote networks interconnection.

 

4.Fiber Optic Patch Cable

 

Fiber optic patch cable, also known as fiber jumper, used to connect from the device to fiber optic cabling link. Fiber jumper has a thick protective layer, generally used in the connection between the fiber converter and Fiber Termination Box. Commonly used fiber jumpers include: ST, LC, FC and SC.

 

Main Categories

 

Single-mode fiber patch cable: General single-mode fiber jumper is colored in yellow, connector and protective sleeve are blue; long transmission distance.

 

Multi-mode fiber patch cable: General multimode fiber jumper is colored in orange and some in gray, connector and protective sleeve are beige or black and the transmission distance is short.

Typical Outdoor Fiber Optic Cables

Fiber optic cable provides protection for the fibers from the environment encountered in an installation. Outdoor Fiber Cable is designed strong to protect the fibers to operate safely in complicated outdoor environment, it can be buried directly, pulled in conduit, strung aerially or even placed underwater. While indoor cables don’t have to be that strong.

 

Outdoor fiber optic cable is composed of many fibers enclosed in protective coverings and strength members. Common features for fiber optic cable include polarization maintaining, graded index, and metalization. Most outdoor fiber cables are loose buffer design, with the strengthen member in the middle of the whole cable, the loose tubes surround the central strength member. Inside the loose tube there is waterproof gel filled, whole cable materials used and gels inside cable between the different components will help make the whole cable resist of water.

Typical outdoor fiber optic cable types are used for aerial, direct buried and duct applications.

 

Loose Tube Cables

 

Loose Tube cables are the most widely used cables for outside plant trunks, as it can be made with the loose tubes filled with gel or water absorbent powder to prevent harm to the fibers from water. Loose Tube Fiber Optic cables are composed of several fibers together inside a small plastic tube, which are in turn wound around a central strength member and jacketed, providing a small, high fiber count cable. They can be installed in ducts, direct buried and aerial/lashed installations for trunk and fiber to the premise applications. Loose tube cables with singlemode fibers are generally terminated by spicing pigtails onto the fibers and protecting them in a splice closure. Multimode loose tube cables can be terminated directly by installing a breakout kit, also called a furcation or fan-out kit, which sleeves each fiber for protection.

 

Ribbon Cable

 

Ribbon cable is preferred where high fiber counts and small diameter cables are needed. This cable has the highest packing density, since all the fibers are laid out in rows in ribbons, typically of 12 fibers, and the ribbons are laid on top of each other. Not only is this the smallest cable for the most number of fibers, it’s usually the lowest cost. Typically 144 fibers in ribbons only has a cross section of about 1/4 inch or 6 mm and the jacket is only 13 mm or 1/2 inch diameter! Some cable designs use a “slotted core” with up to 6 of these 144 fiber ribbon assemblies for 864 fibers in one cable! Since it’s outside plant cable, it’s gel-filled for water blocking or dry water-blocked. These cables are common in LAN backbones and data centers.

 

Armored Fiber Optic Cable

 

Armored cable is used in direct buried outside plant applications where a rugged cable is needed and/or for rodent resistance. Armored cable withstands crush loads well, for example in rocky soil, often necessary for direct burial applications. Cable installed by direct burial in areas where rodents are a problem usually have metal armoring between two jackets to prevent rodent penetration. Another application for armored fiber optic cable is in data centers, where cables are installed under the floor and one worries about the fiber cable being crushed. This means the cable is conductive, so it must be grounded properly.

 

Aerial Fiber Optic Cable

 

Aerial cables are for outside installation on poles. They can be lashed to a messenger or another cable (common in CATV) or have metal or aramid strength members to make them self supporting. A widely used Aerial Cable is optical power ground wire (OPGW) which is a high voltage distribution cable with fiber in the center. The fiber is not affected by the electrical fields and the utility installing it gets fibers for grid management and communications. This cable is usually installed on the top of high voltage towers but brought to ground level for splicing or termination.

 

Indoor/Outdoor Cables

 

Fiber Optic Indoor/Outdoor Cables are designed to meet both the stringent environmental requirements typical of outside plant cable AND the flammability requirements of premise applications. Ideal for applications that span indoor and outdoor environments. By eliminating the need for outside to inside cross-connection, the entire system reliability is improved and with lower overall installation costs.

 

Underwater and Submarine Cables

 

It is often necessary to install fibers under water, such as crossing a river or lake where a bridge other above water location is not possible. For simple applications a rugged direct burial cable may be adequate. For true undersea applications, cables are extremely rugged, with fibers in the middle of the cable inside stainless steel tubes and the outside coated with many layers of steel strength members and conductors for powering repeaters. Submarine cables are completed on shore, then loaded on ships and laid from the ship, often while operational to ensure proper operation.

 

fiber-mart.com offers a comprehensive range of multimode fiber cable and single-mode fiber optic cables. Indoor, outdoor, armoured, tight buffered or loose tube structures, which cover all possible applications.

Why Use Tunable DWDM SFP+ Transceivers?

http://www.fiber-mart.com/fiber-optic-transceivers-sfp-transceivers-c-1_2.htmlThe tunable DWDM SFP+ is one kind of DWDM SFP+ transceivers. They both can be used in the DWDM system. In the market, tunable DWDM SFP+ transceivers are often between two and four times more expensive than DWDM SFP+ transceivers. Thus, many may think DWDM SFP+ transceivers are enough in the DWDM system and wonder why tunable DWDM SFP+ transceivers are also needed. This post will introduce what is tunable DWDM SFP+ transceiver and explain why they need to be used in DWDM systems in details.

 

What’s Tunable DWDM SFP+ Transceiver?

Tunable SFP+ transceivers are a new technology that is in development for a few more years due to the limiting power specifications of the SFP+. They are only available in DWDM form because the CWDM grid is too wide. So a tunable SFP+ transceiver is also called tunable DWDM SFP+ transceiver.

 

The tunable DWDM SFP+ transceiver is equipped with an integrated full C-Band 50GHz tunable transmitter and a high performance PIN receiver to meet the ITU-T (50GHz DWDM ITU-T Full C-band) requirements. It shares the same hot–pluggable SFP+ footprint as DWDM SFP+ transceiver. The major difference between them is that DWDM SFP+ has a fixed wavelength or lambda while the tunable DWDM SFP+ can adjust its wavelength on site to the required lambda. Tunable DWDM SFP+ transceivers enable us to change wavelengths unlimited within the C-band DWDM ITU Grid and can be applied in various types of equipment such as switches, routers and servers.

 

Why Tunable DWDM SFP+ Transceivers Are Used in DWDM Systems?

 

In traditional DWDM systems, fixed-wavelength DWDM SFP+ transceivers are commonly used as light sources in optical communication field. However, as the continuous development, application and promotion of optical communication systems, the disadvantages of DWDM SFP+ transceivers have been gradually revealed. The followings are why tunable DWDM SFP+ transceivers are also needed in DWDM systems:

 

On the one hand, it is essential to prepare backup DWDM SFP+ transceivers for each DWDM wavelength to avoid unnecessary breakdown. In traditional DWDM systems, a small number of extra DWDM SFP+ transceivers are enough. However, with the development of technology, the number of wavelengths in DWDM 50GHz now has reached the hundreds. This means people have to provide up to hundreds of backup DWDM SFP+ transceivers, which will greatly increase the operating cost. Tunable DWDM SFP+ transceivers provide equipment manufacturers and operators with great flexibility, achieving the optimization for the overall network performance and greatly reduce the demand of existing operators for DWDM SFP+ transceiver inventory.

On the other hand, in DWDM systems, it may be required to use a large number of DWDM SFP+ transceivers with different wavelengths to support the dynamic wavelength assignment in optical network and improve network flexibility. But the usage rate of each transceiver is very low, resulting in a waste of resources. The arrival of tunable DWDM SFP+ transceivers has effectively solved this problem. With tunable DWDM SFP+ transceivers, different DWDM wavelengths can be configured and output in the same light source, and these wavelength values and intervals all meet the requirements of ITU-T (50GHz DWDM ITU-T Full C-Band).

 

Conclusion

 

Featuring for flexibly selecting working wavelength, tunable DWDM SFP+ transceivers have very large practical value in optical fiber communication wave division multiplexing system, optical add-drop multiplexer and optical cross-connection, optical switching equipment, light source parts and other applications.

 

Will Single-mode Fiber Work Over Multimode SFP Transceiver?

Network installers usually come across a situation that device you have in your network does not always fit and work perfectly with the fiber. They plan to make a cable plant based on the multimode cabling, but owing to the link limitation or other reasons, they have to connect multimode equipment with single-mode devices. Is it feasible? Or put it more specifically, can I use the multimode SFP over single-mode fibers or vice versa? This article will give you a detailed illustration about the feasibility of the solutions, and introduce two relevant devices (mode conditioning cable and multimode to single-mode fiber media converter).

 

Single-mode Fiber Over Multimode SFP—You Can If You Are Lucky

 

This is the question that has been asked so many time, but no one can give the exact answer—yes or no. Hence, let’s illustrate it in details.

 

Most people think single-mode and multimode fibers are not interchangable because of the wave length of the laser and core size of the fiber. Single-mode fiber (MMF) uses a laser as a light source (the light beam is very concentrated), while multimode fiber (MMF) uses an LED to generate the signal. This would require two significantly different devices to generate the signal.

 

The core sizes are drastically different between SMF and MMF. SMF is 9 micron and multimode is 62.5 or 50 micron. If users try to mix the single-mode and multimode cabling in the same network, they might have trouble dealing with the two different types of signal.

 

However, it is possible to interconnect two devices using SMF interfaces at one end and MMF receiver at the other end. Keep in mind that it depends on the devices, so you can if you are lucky. When plugging LC single-mode duplex fibers on the multimode fiber transceiver (1000GBASE-SX) in the network, you will find the link came up (the light on the switch turns green). Therefore, the multimode fiber transceiver connected by the single-mode fibers works for short-reach application. The following image is the real screenshot of the single-mode fibers inserting into the 1000BASE-SX SFP.

real screenshot of inserting single-mode fiber over multimode fiber transceivers

 

While it should be stressed that the link is not reliable and it only works for particular brand devices with a very short link length. Many sophisticated vendors like Huawei, Alcatel or Cisco do not support it. Nevertheless, owing to the differential mode delay (DMD) effect, signal loss of this connection is not acceptable, either.

 

To sum up, this might be feasible but not advisable. If you need to make a connection between single-mode and multimode interfaces, you’d better use the intermediate switch that is able to convert the signals between single-mode and multimode fibers. The following part will introduce two solutions that might be helpful for the multimode and single-mode conversion.

 

Solution 1: MCP Cable—Single-mode In and Multimode Out

 

As to the multimode fiber with single-mode SFPs, most people mention the mode conditioning patch (MCP) cables. The MCP cable is launched to support 1000BASE-LX optics over multimode cable plant. The mode conditioning cables allow customers to successfully run Gigabit Ethernet over our multimode cable using single-mode fiber transceivers, Cisco 1000BASE-LX/LH SFP is the special type of transceiver that can both support single-mode and multimode fibers. The image below displays the difference between standard SC multimode patch cable and SC mode conditioning patch cable.

 

comparison between standard SC multimode fiber patch cable and SC MCP cable

 

Then, in this situation, you can run successfully from a single-mode fiber transceiver over multimode fiber with the use of MCP cables, but the distance will not exceed the link specification for multimode transceivers. Otherwise, there will be much signal loss in the cable run.

 

In general, if you want to run multimode fiber optic cable over 1000BASE-LX SFPs, you can use the mode conditioning cable. However, mode conditioning patch cords are required for link distances greater than 984 feet (300 meters). For distance less than 300 m, please omit the mode conditioning patch cords (although there is no problem using it on short links).

 

Solution 2: Fiber to Fiber Media Converter—Conversion Between Multimode and Single-mode Fibers

 

As noted before, mode conditioning cables, to some extent, can realize the connection between single-mode to multimode, but you can not say that you can convert single-mode to multimode or vice versa. Mode conversion between multimode and single-mode fibers often requires fiber to fiber media converters or the single-mode to multimode fiber converter.

 

F2F-10G-Multimode-to-Single-mode

 

In the above diagram, two Ethernet switches equipped with multimode fiber ports are connected utilizing a pair of fiber-to-fiber converters which convert the multimode fiber to single-mode and enable network connectivity across the distance between Gigabit switches.

 

Conclusion

 

It doesn’t really make much sense to use the single-mode fiber transceivers with multimode fibers in your network or vice versa, although the link will come up. Like I said above, you can if you are lucky connect. MCP cables and fiber to fiber converter are the two available options for single-mode and multimode connection. If you bought the wrong fiber optic cables, just replace it into the right one. Fiber optic cables and optical transceivers modules nowadays are very cheap. You won’t need to risk of mixing them in the same network.

What You Need To Know About HDMI Cables: The Basics

High-speed HDMI cables can come in a variety of lengths, there’s even a 100 ft HDMI cable out there, and a variety of other options to choose from. They have numerous benefits and the ability to get video resolutions from 480i (standard) all the way to 4k.

 

There are even HDMI to DVI cables for your computer and other devices, giving you the ability to use High-speed HDMI cables on your monitors and dramatically increase your home or office visual experience.

But how do you find the right cable?

 

Buying the right highspeed HDMI cable isn’t overly complicated or difficult. If it’s from a reputable vendor and the right length for your needs, then it should work just fine. You don’t need to spend a fortune on the cables either, which is why purchasing them from quality suppliers is always a good idea.

 

HDMI is an audio-video cable that can send the best image quality and the best sound quality over a single cable. Typically, there are four different types of HDMI cables used today. There is the standard, the standard with ethernet, high-speed, and high-speed with ethernet.

 

Standard cables are good for 720p and 1080i signals and devices, with the ability to handle 1080p in some cases, though not always. For 3D devices, you want an HDMI high-speed with Ethernet cable, as you’ll get the best performance. The HDMI cables with ethernet capabilities allow for data transmissions, and they’re often a good choice for offices and other professional settings.

 

Another great benefit of these cables? You don’t have to worry about different numbered versions of HDMI. To be honest we are not even permitted to mention the version numbers! 3D video, for instance, requires HDMI High-speed with Ethernet, and that might cause an issue with a receiver if you’re daisy-chaining between the 3D capable player and a 3D HDTV. But it won’t be an issue with the cables that you use to do it. It’ll be an issue with the hardware itself.

Brand names are, mostly, unimportant as well, though you should always pick a manufacturer that you can trust. A generic HDMI can be just as good as a more recognized brand, which is a bit unusual in the technology world.

 

If you have questions involving HDMI cables and which one is best for your needs, contact us via the three methods in the blue bar at the top of the page. We’ve got a large amount in stock and can help you pick the right one.

The proper way to store cables

We’ve all experienced it. The crushing dread of pulling out a cable that you need to not only to find that it is a tangled mess but then discover that it no longer works. This can be the nightmare of anyone that works in an industry that relies on wires and cables to help keep equipment working. No matter if you work in audio, video or simply just want cables that you can rely on in order to enjoy media on your devices, having nicely kept cables not only looks great, but can prolong the life of this much needed resource.

One of the big problems with cables is that they can so easily get tangled. Long lengths of wire can be very unwieldy and can be hard to take the time to pack up and secure for future use. Many people who depend on these cords usually do not have the time to devote to standing in one place for long periods of time, wrapping a cord up in their hands. However, the importance of proper cable storage and maintenance should not be underestimated. A properly wrapped cable has the ability to last longer than one that is abused and hastily shoved into a drawer, box or case.

 

Many people are not aware of techniques that can help them save their cables. If a cable is stored improperly or wound the wrong way, it can fray on the inside and can cause damage, leading to the cable malfunctioning. Luckily, learning the proper way to wind and store a cable is very easy. One of the best ways to get started is to simply make a simple loop with the cord in your hand. Then make a loop around in the opposite direction, creating another circle, and coming out in the same place over the fingers again, but inverted. This will reduce the fraying on the inside of the wire and will help prolong the life of the wire. An added benefit is that the cable will not get tangled and all that is needed to unravel it is just to simply start unwinding. The wire will then unravel straight.

However, in order to keep the wire in this form and in order to store it, first leave enough length at the end of the wire in order to thread it through the circle. Then, continue to wrap it around the outside of the circle and through again to the inside, creating a spiral covering the outside of the circle and keeping all of the parts in place.

 

Another great way to wind and store a cable is to start like the above example, but instead of creating a spiral at the end, create a circle at the start and then start a spiral until you run out of wire. This also has the added benefit of shortening the cord so that it takes up less room when in use. Both of the above examples are great ways you can use to help prolong the life of your cables and store them in a quick and easy way.

Allied Fiber opens southeast fiber-optic network route

Allied Fiber, which plans a nationwide open-access, network-neutral colocation and dark fiber network, says that the first links on its southeastern route are ready for service. The newly opened route segment runs 360 miles from Miami, FL to Jacksonville, FL, and is part of a system expected to reach Atlanta (see “Allied Fiber begins installation of Miami-to-Atlanta fiber-optic network route”).

As with the rest of Allied Fiber’s infrastructure, the fiber cable system features a unique design that simplifies connection to the network and to colocation facilities (see “Bubble-era ambition in a post-bubble world”). The three major components are high-count dark fiber cable, handholes for lateral splicing, and integrated, network-neutral colocation facilities. The 528-count fiber-optic cable uses Corning’s SMF 28e+ and LEAF fiber. The cable accessible via handholes installed every 5000 feet along the network.

The newly opened run connects NAP of the Americas in Miami to 421 West Church Street, the main carrier hotel in Jacksonville. In between, the cable provides access to Allied Fiber’s network-neutral colocation facilities in West Palm Beach, Ft. Pierce, Rockledge, New Smyrna Beach, St. Augustine, and Jacksonville. The modular 1200-square-foot facilities are designed to support 64 customer cabinets, 150-kW protected AC 120-V and DC -48-V power, backup generators, HVAC, and 24/7 NOC monitoring services.

“This announcement is a monumental step in Allied Fiber’s evolution to becoming the first national, open-access, integrated network-neutral colocation and dark fiber superstructure in the United States,” said Hunter Newby, CEO of Allied Fiber. “We believe the Florida segment of our Southeast route will serve as a standard for all future segments of our national build where the process and benefits of physical interconnection will be repeated. The impact on all network operators and the communities that they serve across the nation will be to provide access to improved network speeds at more cost effective rates by introducing choice. The access to quality, reduced costs, increased revenue, and improved margins through direct connect options for service providers will result in a significant contribution to overall economic growth and productivity gains throughout the country.”

Multimedia Modular Panel–Flexible Solution for Mixing Fiber and Copper Cabling

No matter we are constructing a copper network or a fiber optic network, inline coupler or fiber adapter always plays an important role in terminating or connecting between two lines. Now both copper networking and fiber optic networking technologies are being developed to meet the continuously increased bandwidth needs. And there are cases where we have to implement mixing fiber and copper link, such as link aggregation through EtherChannel or IEEE 802.3ad standards. Then how to effectively and efficiently couple both copper keystone jacks and fiber optic connectors on one panel? This post will provide the solution by using the multimedia modular panel, which can manage and organize a wide variety of fiber cabling and copper cabling.

 

Why Mixed Fiber and Copper Link?

At first, let’s have a glance at why there is a need for mixing fiber cables and copper cables. Ten years ago, people were asking if it was possible to have copper and fiber as part of the same port-channel group. And now, the term link aggregation is no longer new in constructing network architecture. And EtherChannel technology or IEEE 802.3ad both serves for link aggregation. Link aggregation combines multiple network connections in parallel in order to increase throughput beyond what a single connection could sustain, and to provide redundancy in case one of the links should fail. It groups a number of physical Ethernet links to create a single high-bandwidth data path. It can provide fault-tolerance and high-speed links between switches, routers and servers, and enhance the connection reliability and resilience. It is possible to aggregate copper ports for one link and fiber ports for the second link, but the important thing is to keep the two links at the same speed and as full-duplex. Under this circumstance, multimedia modular panel is designed to achieve the purpose.

 

Benefits of Blank Multimedia Modular Panel

When one link consists of both copper Ethernet patch cables and fiber optic patch cables, the blank multimedia modular panel makes a difference. For standard adapter panels with fixed ports, the patch cable that can be used is limited to one type. For example, every keystone patch panel can hold only one category style Ethernet patch cord, whether it is for Cat5e or Cat6 patch cables; and every preloaded fiber adapter panel can hold only one type of connector, such as single-mode LC APC duplex, LC UPC duplex, multimode SC APC duplex, etc. However, our blank multimedia patch panel is much flexible in copper and fiber mixed implementations. It allows users to aggregate up to six different types of ports at one time. These ports can be either copper or fiber. The inserted keystone jacks or inline couplers can be Cat6a, Cat6, Cat5e or Cat5. And the fiber optic adapters can be standard LC duplex, SC simplex and MTP/MPO. Users can install various port types on demand.

 

 

Moreover, it is very cost-effective as it may avoid port wasting. There are six blank ports on the panel. Generally, users can make use of all of them or deploy suitable number of adapters on it, so as to avoid waste of loaded ports.

 

 

In addition to these two major benefits to the users, multimedia modular panel also has some other good features. It has a two-tier design, and the cover plate on the rear can add mounting stability. Also plastic clips are optional for fiber adapter installation. It will be very easy to configure the snap-in modules on the panel. One bonus this modular panel can bring is that it is fitted with fiber-mart FHD fiber enclosures and cable management panels, which provides a clean, flexible and tidy cable managing for your network.

 

Conclusion

Blank multimedia modular patch panel allows customization of installation for multimedia applications requiring integration of fiber optic cables and copper cables. It is an ideal solution for a mixing copper and fiber link in some implementations. The flexible configuration it brings and cost-effectiveness it owns will no doubt make it a favorite in applications that require multiple port types. Every move, add, or change of coupler on it will be effortless. fiber-mart designed this multimedia modular panel for your convenience in fiber patching and cable management. For more details, please visit fiber-mart.COM.

Fiber Optic Cable are usually used in two scenarios

Fiber Optic Cable are used in applications where the optical signal is too strong and needs to be reduced. For example, in a multi-wavelength fiber optic system, you need to equalize the optical channel strength so that all the channels have similar power levels. This means to reduce stronger channels’ powers to match lower power channels.

The attenuation level is fixed at 5 dB, which means it reduces the optical power by 5dB. This attenuator has a short piece of fiber with metal ion doping that provides the specified attenuation.

There are many different mechanisms to reduce the optical power, this picture shows another mechanism used in one type of variable attenuator. Here variable means the attenuation level can be adjusted, for example, it could be from 1 dB up to 20dB.

Fiber Optic Cable are usually used in two scenarios.

The first case is in fiber optic power level testing. Cable are used to temporarily add a calibrated amount of signal loss in order to test the power level margins in a fiber optic communication system.

In the second case, Cable are permanently installed in a fiber optic communication link to properly match transmitter and receiver optical signal levels.

Optical Cable are typically classified as fixed or variable Cable.

Fixed Cable have a fixed optical power reduction number, such as 1dB, 5dB, 10dB, etc.

Variable Cable’ attenuation level can be adjusted, such as from 0.5 dB to 20dB, or even 50dB. Some variable Cable have very fine resolution, such as 0.1dB, or even 0.01dB.

This slide shows many different optical attenuator designs.

The female to female fixed Cable work like a regular adapter. But instead of minimizing insertion loss, it purposely adds some attenuation.

The female to female variable Cable are adjustable by turning a nut in the middle. The nut adjusts the air gap in the middle to achieve different attenuation levels.

The male to female fixed Cable work as fiber connectors, you can just plug in your existing fiber connector to its female side.

The in-line patch cable type variable Cable work as regular patch cables, but your can adjust its attenuation level by turning the screw.

For precise testing purposes, engineers have also designed instrument type variable Cable. These instrument type Cable have high attenuation ranges, such as from 0.5 dB to 70dB. They also have very fine resolution, such as 0.01dB. This is critical for accurate testing.

How To Repair The Accidentally Cut Fiber Optic Cables

Underground fiber optic cables can be accidentally cut. The most typical factor which could cause this accident may be the utilization of backhoe while digging. If it happens to you, you can simply search for backhoe and obtain the cut cables.

However, if it is brought on by moles, it will likely be difficult for you to troubleshoot it. You will need some equipment to involve. Here are a few steps suggested for you.

The first thing you need to do is to look for the break in your cable. Commonly, the fiber-optic technicians utilize a device which is known as an optical time-domain reflectometer or OTDR. With the ability to work like radar which sends a light pulse right down to the cable. It will be deflected to your device when it encounters break. It helps technician knows the position of the break.

After knowing the location of the break, you should dig up the cable with the break. Then, strip the fiber around 9 feet of the cable using cable rip cord. Peel the jacket gently so the fiber-optic tubes exposed and get rid of the excess jacket. Then, clean that cable gel using cable gel remover and cut any sheath and yarn. Separate the tubes from the fiber. Avoid damaging the strength member as it is required to hold the cable in fiber splice closure.

The next matter you need to do is to expose fiber cladding at 2 inches by using a fiber-coating stripper oral appliance clean the fiber within the tubes. Trim any damage on the fiber ends using high-precision fiber cleaver. If you want to perform a fusion splice, you have to convey a fusion splice protector to the fiber. Hereafter, you have to clean that striped fiber using lint-free wipes that is soaked in alcohol. In addition, if you want to produce a mechanical connection, you need to put quick-connect fiber-optic connectors to the fiber and clean the stripped fiber with alcohol and lint-free wipes. Ensure that the fiber doesn’t touch anything.

If you make a fusion splice, you have to place the fibers which is spliced within the fusion splicer. Then, fire the fusion splicer in line with the manual. After that, you have to move the fusion connector right into a heat shrink oven. Press a button to heat shrink. In some cases, the fusion splice is preferable to mechanical splice because the signal loss is under 0.1 decibels (dB). However, the mechanical splice has signal loss under 0.5 dB. The very last thing would be to see the connection of fiber-optic using the OTDR. Then put back those splices in to the splice enclosure. Close the enclosure after which rebury the cable.

Cabling architectures and communication availability

Ensuring communications remain available is vital during a disaster. If workers in the office lose the internet because of a tornado, the business disruption is a problem, but not nearly as much of an issue as it would be if communications go down completely. Installing cabling architectures that interconnect with telecom infrastructure is a key part of a construction process, and how these systems are deployed can impact communications availability during a disaster. Having alternative network options that can provide emergency communications can also help, ensuring that emergency services can be contacted in the event of a disaster event.

Simplex OM2 50/125 Multimode Fiber Optic Patch Cable

Installing cables to ensure free movement through a building

A poor cabling setup can lead to major problems when disasters strike. Loose wires can clump together, blocking doors, hallways and other areas, preventing people from getting out of a building to escape or into a structure to rescue any trapped individuals. Meeting high standards for safety, including regulations from OSHA and national fire codes can provide a solid foundation for safe and well-designed cable deployment. However, it is important to also consider the quality of the components that keep cables in place and how the wiring systems are laid out in the building to ensure they do not become obstructions during a disaster.

Cabling installation methods could mean the difference between life and death during a disaster. When a tornado or hurricane hits an area, employees must be able to get to safety, or get help, as quickly as possible. Cables that get in the way can be a detriment to this process, but a well-designed system will not only stay out of the way, it could help keep key communication channels available.

The advantages of Cisco CWDM/DWDM solutions

The Cisco CWDM solutions are built on the Gigabit Interface Converter (GBIC) technology to support the gigabit Ethernet services. The Cisco CWDM GBIC products can be inserted into the Cisco switches and routers.

The Cisco DWDM products are based on the wireless fiber media converter. And these Cisco DWDM products support many services such as the gigabit Ethernet, Fibre Channel, OC-x, ESCON/FICON and the DSx service. The Cisco DWDM products also can be connected to the Cisco switches and routers.

 If you think that the Cisco products, such as, fiber optic transceivers, are very expensive. You come to the right place. We provide CWDM GBIC transceivers, DWDM GBIC modules, SFP+ modules, X2 modules and other fiber optic modules with the high performance and the lower price. And these products are all compatible with Cisco and other brands’ equipment.

Do you really know 1000BASE-LX / LH SFP?

1000BASE-LX/LH SFP1000BASE-LX LH SFP, one of the commonly used fiber optic transceivers, is now widely used in optical transmission systems. With the development of 40/100G Ethernet, even 400G Ethernet, this kind of transceiver module is nothing new to the module users. However, few people can deliver a clear answer to the question of what “1000BASE-LX / LH” infers. Well, if you know what it means, congratulations! you are the one of the few. You can skip today’s contents or share your experience to us in the comment. Actually, this post is a simple reference source for the beginners in this field or those who are lack of knowledge with fiber optic transceiver but have a strong interest in it.

To begin with, I’d like to make a brief introduction of 1000BASE-LX / LH SFP. This kind of SFP is similar with the other SFPs in basic working principle and size. But it is compatible with the IEEE 802.3z 1000BASE-LX standard, operating on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers. In addition, when used over legacy multimode fiber type, the transmitter should be coupled through a mode conditioning patch cable (see Earlier article: Why Mode Conditioning Patch Cable Necessary for 1000Base-LX / LH Application).

 

As we know, an optical transceiver module is generally either made for single mode (long distance) or multimode (short distance). But 1000BASE-LX / LH SFP can be used for both singlemode and multimode. In fact, the Ethernet standard defines this optical interface specification as 1000BASE-LX10. However, many vendors as a proprietary extension called either 1000BASE-LX / LH or 1000BASE-LH before it was standardized. Thus, we often see 1000BASE-LX / LH rather than 1000BASE-LX10.

 

In a word, 1000BASE-LX / LH SFP has two identities. It is single mode by design, but when it gets together with its friend “mode conditioning patch cable“, it can also be used for multimode application. This patch cable inserts a single to multi splice on the transmit path, to “fill” the multimode fiber with light. It is more expensive than normal patch cables, but is necessary if using these on multimode fiber. At present, 1000BASE-LX / LH SFP is the only one kind of fiber optic transceivers which can be used for both singlemode and multimode applications. And these applications are depending on what fiber you use.

 

The FOA Reference For Fiber Optics

Fiber Optic Transmitters and Receivers (Transceivers)

 

Fiber optic transmission systems (datalinks) all work similar to the diagram shown above. They consist of a transmitter on one end of a fiber and a receiver on the other end. Most systems operate by transmitting in one direction on one fiber and in the reverse direction on another fiber for full duplex operation.

 

Most systems use a "transceiver" which includes both transmission and receiver in a single module. The transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant. The light from the end of the fiber is coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment.

 

The sources used for fiber optic transmitters need to meet several criteria: it has to be at the correct wavelength, be able to be modulated fast enough to transmit data and be efficiently coupled into fiber.

Four types of sources are commonly used, LEDs, fabry-perot (FP) lasers, distributed feedback (DFB) lasers and vertical cavity surface-emitting lasers (VCSELs). All convert electrical signals into optical signals, but are otherwise quite different devices. All three are tiny semiconductor devices (chips). LEDs and VCSELs are fabricated on semiconductor wafers such that they emit light from the surface of the chip, while f-p lasers emit from the side of the chip from a laser cavity created in the middle of the chip. 

 

LEDs have much lower power outputs than lasers and their larger, diverging light output pattern makes them harder to couple into fibers, limiting them to use with multimode fibers. Laser have smaller tighter light outputs and are easily coupled to singlemode fibers, making them ideal for long distance high speed links. LEDs have much less bandwidth than lasers and are limited to systems operating up to about 250 MHz or around 200 Mb/s. Lasers have very high bandwidth capability, most being useful to well over 10 GHz or 10 Gb/s.

 Because of their fabrication methods, LEDs and VCSELs are cheap to make. Lasers are more expensive because creating the laser cavity inside the device is more difficult, the chip must be separated from the semiconductor wafer and each end coated before the laser can even be tested to see if its good.

LEDs have a limited bandwidth while all types of lasers are very fast. Another big difference between LEDs and both types of lasers is the spectral output. LEDs have a very broad spectral output which causes them to suffer chromatic dispersion in fiber, while lasers have a narrow spectral output that suffers very little chromatic dispersion. DFB lasers, which are used in long distance and DWDM systems, have the narrowest spectral width which minimizes chromatic dispersion on the longest links. DFB lasers are also highly linear (that is the light output directly follows the electrical input) so they can be used as sources in AM CATV systems.

 

The choice of these devices is determined mainly by speed and fiber compatibility issues.  As many premises systems using multimode fiber have exceeded bit rates of 1 Gb/s, lasers (mostly VCSELs) have replaced LEDs. The output of the LED is very broad but lasers are very focused, and the sources will have very different modal fill in the fibers. The restricted launch of the VCSEL (or any laser) makes the effective bandwidth of the fiber higher, but laser-optimized fiber, usually OM3, is the choice for lasers.

 

The electronics for a transmitter are simple. They convert an incoming pulse (voltage) into a precise current pulse to drive the source. Lasers generally are biased with a low DC current and modulated above that bias current to maximize speed.

 

Detectors for Fiber Optic Receivers

 

Receivers use semiconductor detectors (photodiodes or photodetectors) to convert optical signals to electrical signals. Silicon photodiodes are used for short wavelength links (650 for POF and 850 for glass MM fiber). Long wavelength systems usually use InGaAs (indium gallium arsenide) detectors as they have lower noise than germanium which allows for more sensitive receivers.

 

Packaging

Transcivers are usually packaged in industry standard packages like these XFP modules for gigabit datalinks(L) and Xenpak (R). The XFP modules connect to a duplex LC connector on the optical end and a standard electrical interface on the other end. The Xenpak are for 10 gigabit networks but use SC duplex connection. Both are similar to media converters but are powered from the equipment they are built into.

 

Performance

Just as with copper wire or radio transmission, the performance of the fiber optic data link can be determined by how well the reconverted electrical signal out of the receiver matches the input to the transmitter. The discussion of performance on datalinks applies directly to transceivers which supply the optical to electrical conversion.

Every manufacturer of transceivers specifies their product for receiver sensitivity (perhaps a minimum power required) and minimum power coupled into the fiber from the source. Those specifications will end up being the datalink specifications on the final product used in the field.

All datalinks are limited by the power budget of the link. The power budget is the difference between the output power of the transmitter and the input power requirements of the receiver. The receiver has an operating range determined by the signal-to-noise ratio (S/N) in the receiver. The S/N ratio is generally quoted for analog links while the bit-error-rate (BER) is used for digital links. BER is practically an inverse function of S/N.

 

SIMPLE FUSION SPLICING GUIDE

Fusion Splicing is simply joining two optical fibers together by making use of heat. The two optical fibers should be fused in such as way as to allow light to be passed through them without scattering or reflecting light back at the point of the splice. The heat used to fuse the two fibers together is usually in the form of an electric arc, however it can also be achieved using a laser or even gas flame, but these methods are considered dated and inferior . This very simple Fusion Splicing guide should help to explain the process without getting too technical.

 

What You’ll Need

 

Fiber Strippers

Kevlar Cutter

Splice Sleeves

Alcohol Wipes

Fiber Optic Cleaver

Microscope (Not mandatory, but very useful for checking fiber ends)

Fusion Splicer

 

Step 1: Stripping the Fibers

It sounds simple enough right? Unfortunately this is not quite as simple as stripping the simple coating of your average house-hold copper cable. In this case you will first be removing the polymer coating by making use of Fiber Strippers, which are specially designed for stripping the coating off the fiber. Ideally 1 and half inches (40 mm) should be removed  from each end of the fiber you are joining. This should be done incrementally and gently while ensuring the stripper is held at a slight angle during the process.

 

With the coating stripped from the fibers it is now time to simply clip away any excess, exposed Kevlar with your Kevlar cutter. Once completed slide one of your Splice Sleeves onto one of your fiber, you may not be able to do this once you have spliced the two fibers together so it is best to do it now.

 

Step 2: Clean, Cleave and Clean

 

Keeping the fibers clean is of the utmost importance when it comes to fusion splicing. It cannot be repeated enough, ensure that the fibers you are working with are cleaned after every major interaction with them. You do this by gently wiping them down with Alcohol Wipes.

 

Once clean it is time to cleave the fibers. The fiber should ideally be cleaved using what is know as the score-and -break method, this is done to ensure that the end face is perfectly flat and perpendicular to the axis of the fiber. This is best done by making use of a quality Fiber Optic Cleaver. The closer the cleave angle is to 90 degrees on both fibers the better, this will result in less optical loss from the splice. After cleaving both fibers it is time to once again clean the ends with the Alcohol Wipes.

 

Step 3: Fusion Splicing

 

It is now time to make use of your Fusion Splicer, begin by placing each fiber into the guides on the Fusion Splicer and clamp them into places securely. Close the lid of the splicer and be sure to select the correct settings on the monitor and program in the correct fiber types into the Fusion Splicer. The fiber ends will be automatically moved into position, at this point a prefuse cycle will begin and any remaining dirt on the fiber ends will be removed as preheating begins. Next the fusion splicer will attempt to align the two fibers by inspecting the cleaves, bad cleaves will result in misalignment and will be rejected. If the cleaves are good the fibers will be fused by an automatic arc cycle that heats the ends and feeds the fibers together at a controlled rate.

Once fusion has been completed the Fusion Splicer will inspect the splice and estimate the total optical loss of the splice. Should it need to be remade it will inform you. If all goes according to plan it is now time to remove the fibers from the guides and move the splice protector over the splice and shrink it to fit (Most splicing machines have a heating device for heat shrinking protective sleeves).

 

As previously mentioned, this is a very simple guide. There are many variables that must be taken into account when you are splicing different types of fiber. So while it is difficult to get down to specifics hopefully this guide should give you a good idea of the process as a whole and get you started. Just remember to take your time while splicing in order ensure a good clean splice, it will save time in the long run.