Category Archives: Fiber Optic Testers

FiberStore offers a selection of Fiber Tester and Fiber Optic Tools to fit any job. We stock top high quality Test Equipment for the communications applications. In the fiber optic installation and maintenance works, Optical Power Meters, Fiber Light Sources, Fiber Scopes and OTDR are commonly used for fiber optic testing.

What Should You Know Before Using an OTDR?

OTDR, the optical time domain reflectometer, is the most important investigation tool for optical fibers. It’s applied in the measurement of fiber loss, connector loss and for the determination of the exact place and the value of cable discontinuities. It’s the only device which can verify inline splices on concatenated fiber optic cables and locating faults.

To know how to use OTDR for the fiber investigations, first you should know the structure and working principle of OTDR equipment. When a short light pulse transmits into the fiber under test, the time of the incidence and the amplitude of the reflected pulses are measured. The commonly used pulse width ranges from nanosecs to microsecs, the power of the pulse can exceed 10 mW. The repetition frequency depends on the fiber length, typically is between 1 and 20 kHz, naturally it is smaller for longer fibers. The division by 2 at the inputs of oscilloscope is needed since both the vertical (loss) and the horizontal (length) scales correspond to the one-way length.

jdsu-mts-4000-otdr

Besides, to use an OTDR successfully, you should also know how to operate the instrument. The following is about the experiences collected from some experienced people who use OTDRs during installation and for maintaining telecommunication networks.

Keep Connectors Clean

Before use OTDR, first, you should watch out if the connectors are clean. If it’s dirty, then clean it. Otherwise, it will make measurements unreliable, noisy or even impossible. What’s worse, it may damage the OTDR.

Check the Connector or the Patch Cord

Check whether the patch cord, the module, and the fiber under test are single-mode or multimode. To test the patch cord, activate the laser in the CW (Coarse Wavelength) mode and measure the power at the end of the patch cord with a power meter. This should be between 0 and – 4 dBm for most single-mode modules and wavelengths.

Set the Range

The range is the distance over the cable which the OTDR will measure. The range should be longer than the cable you are testing. For example, if your link is 56.3 km long, choose 60 km. For distances greater than approximately 15 km, make your first measurement in longhaul mode, otherwise use shorthaul.

Determine the Wavelength

Usually single-mode is set for 1310 nm or 1550 nm, and multimode is set for 850 nm or 1300 nm.

Averages of Noisy Traces

If the trace is very noisy, increase the number of averages. Usually 16-64 averages are adequate. To improve the signal to noise ration of the trace, the OTDR can average multiple measurements, but averaging takes time. So try to average over a longer time.

Realtime Mode

In this mode, you can modify parameters only if you stop a measurement explicitly. So it avoids you to erase a trace averaged over a long time by accident. You use realtime mode to check your connection, the quality of splices, and whether a fiber is connected. Start in automatic mode, then switch to realtime mode and select the most suitable parameters.

Adjust the Refractive Index

If you know the exact physical length of the fiber under test, you can measure the refractive index. Start with the refractive index 1.5000. Place a marker at the end of the fiber. Then select the refractive index function and adjust it until the displayed marker position is equal to the known fiber length. Then, the effective refractive index will be displayed.

Macrobending Loss

Single-mode fibers (1550 nm) are very sensitive to macrobending such as a tight bend or local pressure on the cable. It doesn’t always happen at this wavelength of 1310 nm. So characterize your link at both wavelengths.

OTDRs are invaluable test instruments. Maybe a small mistake will cause serious damage to this equipment. So before use it, you should better know it as detailed as possible to avoid any loss because of innocence and make full use of it in optical fiber events.

Related article:
How to Choose a Right OTDR?
OTDR Selection Guide

How to Choose a Right OTDR?

An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to measure fiber loss, the loss and reflectance of fiber splices, and to locate loss irregularities within the fiber. Now there are many types of OTDRs providing different test and measurement needs including very simple fault finders and advanced OTDRs for link certification. Then, how to choose the right one?

aq1200-mft-otdr

First, you should evaluate your needs. Installing or maintaining fiber? For simple maintenance, a simple or low cost OTDR is good. It’s easy to use, requires the lowest possible investment and some even provides total link loss and optical return loss values. For not very complex installation, you should choose a mini OTDR based on the following key parameters for your specific environment.

Dynamic Range

This specification determines the total optical loss that the OTDR can analyze; i.e., the overall length of a fiber link that can be measured by the unit. The higher the dynamic range, the longer the distance the OTDR can analyze. Insufficient dynamic range will influence the ability to measure the complete link length and affect the accuracy of the link loss, attenuation and far-end connector losses. It’s good to choose an OTDR whose dynamic range is 5 to 8 dB higher than the maximum loss you will encounter.

Dead Zones

Dead zones originate from reflective events (connectors, mechanical splices, etc.) along the link, and they affect the OTDR’s ability to accurately measure attenuation on shorter links and differentiate closely spaced events, such as connectors in patch panels, etc. There are two types of dead zones to specify OTDR performance:

Attenuation dead zone refers to the minimum distance required, after a reflective event, for the OTDR to measure a reflective or non-reflective event loss. Try to choose OTDR with the shortest possible attenuation dead zone to measure short links and to characterize or find faults in patchcords and leads. Industry standard values range from 3 m to 10 m for this specification.

Event dead zone is the distance after a reflective event starts until another reflection can be detected. If a reflective event is within the event dead zone of the preceding event. Industry standard values range from 1 m to 5 m for this specification. The event dead zone specification is always smaller than the attenuation dead zone specification.

Sampling Resolution

Sampling resolution refers to the minimum distance between two consecutive sampling points acquired by the instrument. This is a quite important parameter as it defines the ultimate distance accuracy and fault-finding capability of the OTDR.

Pass/Fail Thresholds

This parameter is also important because lots of time can be saved in the analysis of OTDR traces if you set Pass/Fail thresholds for parameters of interest (e.g., such as splice loss or connector reflection). These thresholds highlight parameters that have exceeded a Warning or Fail limit set and, when used in conjunction with reporting software, it can rapidly provide re-work sheets for installation/commissioning engineers.

Report Generation

If an OTDR has specialized post-processing software allowing fast and easy generation of OTDR reports, it can save up to 90% post-processing time. These can also include bidirectional analyses of OTDR traces and summary reports for high-fiber-count cables.

To choose a right OTDR for your test application, you should better consider the above factors. Fiberstore offers YOKOGAWA AQ1200A, EXFO AXS-110-23B-04B OTDR, etc,. with great accuracy, measurement range and instrument resolution. There must be one suitable for you and helpful to maximize your return on investment.

Originally published at http://www.articlesfactory.com/articles/communication/how-to-choose-a-right-otdr.html

Related article: What Should You Know Before Using an OTDR?

Introduction of Network Tester

Network tester is a device used for logging and monitoring your internet connection, network or maintain uptime stability. It is a dispensable tool for managers to troubleshoot network problems and maintain the network actively, such as troubleshooting your video, audio, data, and voice network cables during installation or testing to make sure your signal is good.

Network testers can be divided into different types depending on two standards: network transmission and function media. By network transmission media they can be divided into two kinds: wireless network testers and line network testers. And by its function they can be classified into three types: cable testers, multifunction network testers and network performance testers. Of those various types of testers, the most common used network tester for network administrators and installers is cable tester which is designed to test the strength and connectivity of a particular type of cable or other wired assemblies. It can test whether cables or wires are set up and connected appropriately and if the communication strength between the source and destination is strong enough to serve its intended purpose.

Network Cable TesterNetwork testers are mainly applied in two aspects, one is testing and maintaining the equality and data of network construction equipment which is widely used in comprehensive wiring system. Another is troubleshooting problems of network maintenance equipment which attached importance to products’ multiple functions and applications. And network testers are utilized in a wide range of fields including LAN administration, comprehensive wiring system, data centres, bandwidth operation, and network computer lab.

There are few tips for you when using network tester.

  • Some important network characteristics including utilisation levels, number of users, and application utilisation must be noticed and each network should be evaluated individually.
  • Comprehensive network testing will enable a network manager to maintain the network with high efficiency. So a properly implemented network testing schedule is of high importance which provides a valuable insight to trends or changes in the network’s daily operation. This insight may allow the network manager to predict network operation under a given load, or anticipate problems created by new services.

Fiberstore offers various network cable testers, from basic to complicated,with high quality at good prices. FiberStore supplies so many kinds of LAN Network Cable Tester, which are a kind of convenient and comprehensive tool for network professionals.

Understanding Fiber Optic Based Light Source

Each piece of active electronics will have a variety of light sources used to transmit over the various types of fiber. The distance and bandwidth will vary with light source and quality of fiber. In most networks, fiber is used for uplink/backbone operations and connecting various buildings together on a campus. The speed and distance are a function of the core, modal bandwidth, grade of fiber and the light source, all discussed previously. Light sources of the fiber light source are offered in a variety of types. Basically there are two types of semiconductor light sources available for fiber optic communication – The LED sources and the laser sources.

Using single mode fiber for short distances can cause the receiver to be overwhelmed and an inline attenuator may be needed to introduce attenuation into the channel. With Gigabit to the desktop becoming commonplace, 10Gb/s backbones have also become more common. The SR interfaces are also becoming common in data center applications and even some desktop applications. As you can see, the higher quality fiber (or laser optimized fiber) provides for greater flexibility for a fiber plant installation. Although some variations ( 10GBase-LRM SFP+ and 10GBASE-LX4) support older grades of fiber to distances 220m or greater, the equipment is more costly. In many cases, it is less expensive to upgrade fiber than to purchase the more costly components that also carry increased maintenance costs over time.

Light sources of the fiber light source are offered in a variety of types. Basically there are two types of semiconductor light sources available for fiber optic communication – The LED sources and the laser sources.

In fiber-optics-based solution design, a bright light source such as a laser sends light through an optical fiber, called laser light source . Along the length of the fiber is an ultraviolet-light-treated region called a “fiber grating.” The grating deflects the light so that it exits perpendicularly to the length of the fiber as a long, expanding rectangle of light. This optical rectangle is then collimated by a cylindrical lens, such that the rectangle illuminates objects of interest at various distances from the source. The bright rectangle allows line scan cameras to sort products at higher speeds with improved accuracy.

The laser fiber-based light source combines all the ideal features necessary for accurate and efficient scanning: uniform, intense illumination over a rectangular region; a directional beam that avoids wasting unused light by only illuminating the rectangle; and a “cool” source that does not heat up the objects to be imaged. Currently employed light sources such as tungsten halogen lamps or arrays of light-emitting diodes lack at least one of these features.

Choose The Right Fiber Optic Tools For Cable Splicing And Terminating

Correctly splicing and terminating fiber optic cable requires special tools and methods. Training is essential and there are many excellent causes of training available. Do not mix your electrical tools with your fiber tools. Use the right tools to do the job! Being experienced in fiber work will end up increasingly necessary because the importance of data transmission speeds, fiber towards the home and fiber to the premise deployments still increase.

Many factors set fiber installations apart from traditional electrical projects. Fiber optic glass is very fragile; it’s nominal outside diameter is 125 micron. The slightest scratch, mark or perhaps speck of dirt will affect the transmission of light, degrading the signal. Safety factors are important because you will work with glass that can sliver to your skin without being seen through the human eye. Transmission grade lasers are extremely dangerous, and require that protective eyewear is a must. This industry has primarily been coping with voice and data grade circuits that may tolerate some interruption or slow down of signal. The person speaking would repeat themselves, or even the data would retransmit. Today we are dealing with IPTV signals and customers who’ll not tolerate pixelization, or momentary locking from the picture. All the situations mentioned are reason for the client to look for another carrier. Each situation might have been avoided if proper attention was handed towards the techniques used when preparing, installing, and maintaining fiber optic cables.

Jacket Strippers are utilized to remove the 1.6 – 3.0mm PVC outer jacket on simplex and duplex fiber cables. Fiber Cutters will cut and trim the kevlar strength member directly underneath the jacket and Buffer Strippers will take away the acrylate (buffer) coating from the bare glass. A protective plastic coating is used to the bare fiber after the drawing process, but just before spooling. The most typical coating is really a UV-cured acrylate, that is applied in two layers, producing a nominal outside diameter of 250 micron for that coated fiber. The coating is highly engineered, providing protection against physical damage caused by environmental elements, such as humidity and temperature extremes, contact with chemicals, reason for stress… etc. whilst minimizing optical loss. Without it, the manufacturer wouldn’t be in a position to spool the fiber without breaking it. The 250 micron-coated fiber may be the building block for a lot of common fiber optic cable constructions. It is usually used as is, particularly when additional mechanical or environmental protection is not needed, for example inside of optical devices or splice closures. For additional physical protection and easy handling, a secondary coating of polyvinyl chloride (PVC) or Hytrel (a thermoplastic elastomer that has desirable characteristics to be used as a secondary buffer) is extruded within the 250 micron-coated fiber, increasing the outside diameter as much as 900 micron. This kind of construction is called ‘tight buffered fiber’. Tight Buffered may be single or multi fiber and are observed in Premise Networks and indoor applications. Multi-fiber, tight-buffered cables often can be used for intra-building, risers, general building and plenum applications.

‘Loose tube fiber’ usually includes a bundle of fibers enclosed inside a thermoplastic tube referred to as a buffer tube, which has an inner diameter that is slightly larger than the diameter of the fiber. Loose tube fiber has a space for the fibers to grow. In a few climate conditions, a fiber may expand after which shrink over and over again or it may be exposed to water. Fiber Cables will sometimes have ‘gel’ within this cavity (or space) yet others that are labeled ‘dry block’. You will find many loose tube fibers in Outside Plant Environments. The modular design of loose-tube cables typically stands up to 12 fibers per buffer tube with a maximum per cable fiber count in excess of 200 fibers. Loose-tube cables can be all-dielectric or optionally armored. The armoring is used to protect the cable from rodents such as squirrels or beavers, or from protruding rocks in a buried environment. The modular buffer-tube design also permits easy drop-off of categories of fibers at intermediate points, without disturbing other protected buffer tubes being routed to other locations. The loose-tube design also helps in the identification and administration of fibers within the system. When protective gel is present, a gel-cleaner such as D-Gel will be needed. Each fiber will be cleaned with the gel cleaner and 99% alcohol. Clean room wipers (Kim Wipes) are a good choice to use with the soap. The fibers inside a loose tube gel filled cable will often have a 250 micron coating so that they tend to be more fragile than the usual tight-buffered fiber. Standard industry color-coding can also be accustomed to identify the buffers along with the fibers in the buffers.

A ‘Rotary Tool’ or ‘Cable Slitter‘ can be used to slit a diamond ring around and thru the outer jacketing of ‘loose tube fiber’. Once you expose the durable inner buffer tube, you can use a ‘Universal Fiber Access Tool’ that is designed for single central buffer tube entry. Utilized on the same principle because the Mid Span Access Tool, (which allows access to the multicolored buffer coated tight buffered fibers) dual blades will slit the tube lengthwise, exposing the buffer coated fibers. Fiber handling tools such as a spatula or perhaps a pick can help the installer to access the fiber in need of testing or repair. Once the damaged fiber is exposed a hand- stripping tool will be used to take away the 250 micron coating in order to work with the bare fiber. The next step is going to be cleaning the fiber end and preparing it to be cleaved. A great cleave is among the most important factors of manufacturing a low loss on the splice or a termination. A Fiber Optic Cleaver is really a multipurpose tool that measures distance in the end of the buffer coating enough where it will likely be joined also it precisely cuts the glass. Always remember to utilize a fiber trash-can for that scraps of glass cleaved from the fiber cable.

When performing fusion splicing you may need a Fusion Splicer, fusion splice protection sleeves, and isopropyl alcohol and stripping tools. If you are using a mechanical splice, you will need stripping tools, mechanical splices, isopropyl alcohol and a mechanical splice assembly tool. When hand terminating a fiber you will need 99% isopropyl alcohol, epoxy/adhesive, a syringe and needle, polishing (lapping) film, a polishing pad, a polishing puck, a crimp tool, stripping tools, fiber optic connectors (or splice on connectors) and piano wire.

Whenever a termination is complete you have to inspect the finish face of the connector having a Fiber Optic Inspection Microscope. Ensuring light is getting most likely through the splice or even the connection, a visible Fault Locator may be used. This piece of equipment will shoot a visible laser down the fiber cable so you can tell there are no breaks or faulty splices. If the laser light stops on the fiber somewhere, there’s most likely a break in the glass at that point. If you find more than a dull light showing in the connector point, the termination was not successful. The light should also pass through the fusion splice, if it does not, stop and re- splice or re-terminate.

Fiberguide Can Provide Fiber Optic Retail And Local Inventory Service




Summarize

With the requirement of the high energy laser and special fiber optical sensing application market has become increasingly active in China market, more and more customers need to use small quantities (<20m) of fiber to carrying research and development test, mass production until the system pass the verification assessment.

FiberStore news, US-based specialty fiber solutions provider Fiberguide had announced that it can provide RMB settlement, fiber optic retail and local inventory and other services.

With the requirement of the high energy laser and special fiber optical sensing application market has become increasingly active in China market, more and more customers need to use small quantities (<20m) of fiber to carrying research and development test, mass production until the system pass the verification assessment. It requires international fiber optic providers to be more flexible and respond more quickly. Fiberguide, comply with the requirements of customers, has been completed the whole work of RMB settlement  and fiber optic products local stocks, fiber can be sold by meter, always running stock fiber optic products and delivery within one week after payment.

Providing fiber retail and local inventory are important parts of Fiberguide’s work plan in Chinese market. The first regular standing fiber will include the Polyimide high-temperature fiber whose temperature can reach up to 350��, as well as Japanese double-clad high power fiber (size 200/500/780/1300, 300/500/780/1300, 400/500/780/1300) and so on. Fiberguide will timely add more varieties of fiber based on customer feedback.

The first batch of domestic customers purchasing retail specialty fiber is gold plated. Fiberguide believes that hot sale products will be Japanese double-clad high-power fiber and single-use medical fiber which are widely used in the market, relevant preparation work is carrying on in order.