CWDM System Testing Process

With the explosion of CWDM, it is very necessary to formulate a basic testing procedure to certifying and troubleshooting CWDM networks during installation and maintenance. Today, one of the most commonly available test methods is the use of an OTDR or power source and meter, which is capable of testing the most commonly wavelengths, 1310, 1490, 1550 and 1625nm.

This article here is based on the pre-connectorized plug and play CWDM systems that allow for connecting to test equipment in the field:

In the multiplexing module of a pre-connectorized CWDM system, wavelengths are added to the network through the filters and transmitted through the common port. The transmitted wavelengths enter the COM port in the de-multiplexing module and are dropped. All other wavelengths present at the MUX/DeMux module are went through the express port.

Most of today’s OTDRs have expanded capability for testing wavelengths in addition to 1310 and 1550 nm. The OTDR allows partial testing of such system offered in test equipment source. The OTDR allows partial testing of these systems by using the flexibility of pre-connectorized solutions. This is done by switching connections within the CWDM field terminal to allow for testing portions of the non-1310/1550 nm optical paths.

To test the 1310nm, the first step is to test the downstream portion of a system at 1310 nm by connecting the OTDR to the 1310 nm input on the CWDM MUX located at the headend. Then switch the test leads over the the upstream side and repeat. Test method is the same for both the downstream and upstream paths.

1550 nm testing is performed similarly by switching the test leads to the 1550nm ports. If additional wavelengths are present, you need to follow the procedures below:

Using the 1550 nm test wavelength, switch the OTDR connection to the 1550 nm input port on the headend MUX. Have a technician stationed at the field terminal connect the drop cable leg connectors for the 1570 nm customer to the 1550 nm port on the Mux/demux device. What should be noted is that in a play and plug solution this should not require repositioning where the drop cable passes through the OSP terminal. Test the downstream 1570 nm passive link at 1550 nm, and then repeat for the 1570 nm upstream side. When testing is complete, have the technician switch the connections for the 1570 nm drop back to the 1570 nm ports on the field MUX/DeMUX device as shown in Figure 6. Repeat this process for the 1590 nm, 1610 nm drop cables and other wavelengths present. Finally, test the 1550 nm path normally with the 1550 nm drop cable connected to the 1550nm MUX/DeMUX ports.

Since the OTDRs is able to test at 1490 or 1625 nm, the drop cables under test could be connected to the EXP port of the module and tested at 1490 or 1625 nm respective wavelength, without having to connect each to the 1550 nm port. Otherwise the procedure is the same.

As CWDM network become more and more common the data they carrying has also become critical. The procedure introduced here allows for testing modular pre-connectorized CWDM systems with standard optical test equipments. Relative channel power can be measured with a wide-band fiber optic power meter at the filter outputs or at other points in the network with the aid of a wavelength selective test device or with an optical spectrum analyzer.

Overview of Miller Fiber Optic Stripper

Miller is a diversified global company specialized in high-tech products in development. It’s diverse business involves in welding, cable & wire tools, winery, furniture and even textile. Miller Cable & wireless tools are very famous fiber optic tools that feature top technology and perfect performance.

FiberStore, as the major global fiber optic tools provider, is proud to become the agent for the original Miller fiber optic tools. Our Miller fiber optic tools include fiber scribers, cable Strippers, cutting tools and Kevlar shears.

A precise stripper is utilized to remove the buffer coating of the fiber itself for termination. There are three types of fiber strippers available, known as the Miller Stripper, No-Nik and Micro-Strip. These three can work equally well, and most techs choose the one they are most acquainted with. The Miller striper is used on the left thus has the disadvantage of being “right-handed”, Which is considered to be the most rugged. The No-Nik is careful with the fiber but requires careful cleaning. Check out the original Miller Fiber optic stripper features:

Miller Fiber Optic Stripper FO 103-D-250
New Dual holes models offer he same quality of our standard FO 103-S fiber tool coupled with a second hole
FO 103-D-250: Second hole for stripping 900 micron tight buffer down to 250 micron buffer coating and standard 125 micron fiber stripping (250 micron removal to 125 micron) – allows longer
Stripping lengths without damaging the fiber
Easy-to-read stripping diagrams imprinted on handles
Made in the U.S.A.
Length: 5.375 in (137mm)
Weight: 2.5 oz (71g)

Miller Fiber Optic Stripper FO 103-T-250-J
New three-hole model performs all common fiber stripping functions in one compact tool….
Hole for removal of 2 to 3 mm fiber jackets
Remove 900 tight buffer to 250 micron buffer coating
Standard 250 to 125 micron stripping
Same consistent quality and features found in our standard FO 103-S tool
Made in the U.S.A.
Length: 5.375 in (137mm)
Weight: 2.5 oz (71g)

Miller FO 103-S Fiber Optic Stripper
For stripping 250 micron buffer coating from 125 micron optical fiber
Precision diameter hole & V-opening in blade allow for accurate buffer coating removal
NEW pivot pin, spring and precision handles enhances tool functionality and durability
Factory set, requires no adjustment
Prevents scratching or nicking of optical fiber
All cutting surfaces are precision formed, hardened, tempered and ground assuring precise buffer removal
Made in the U.S.A.
Length: 5.375 in (136.53mm)
Weight: 2.5 oz (71g)

Miller Fiber Optic Stripper CFS-2
For stripping 250 micron buffer coating to expose 125 micron cladding fiber
Second hole for stripping 2-3mm fiber jackets
140 µm diameter hole and V-opening in blade allows removal of 250 micron buffer coating from 125 micron fiber
Pre-set at the factory – no adjustments needed
Will not scratch or nick glass fiber
All stripping surfaces are manufactured to precise tolerances to assure clean, smooth strips
Comfort-grip, ergonomic handles
Lock to hold tool closed when it is not in use
Length 6.43 in (165.00mm)
Weight 4.17 ounces (119.0g)

Most strippers are “sized” for the fiber coatings to be removed. So ensure you have the proper stripper for the fiber being stripped. Whichever stripper is used. Care must be taken to not nick the Fiber during the stripping process as it can cause cracks that may lead to fiber failure sometime in the future. Strippers require careful cleaning and immediate replacement if they become damaged or worn.

Strippers are sized for the fiber coatings to be removed. So ensure you have the proper stripper for the fibers to be stripped. Whichever stripper is used, you must take care to not nick the fiber during the stripping process as it can cause cracks that may lead to fiber failure sometime in the future. supplies various of high quality fiber optic tools individually or in kits, most of the price is extremely cheap, even the fiber optic tool kit price is with attractive discount rate.

Find Hidden Cables with Cable Wire Locators

Locating buried and hidden lines prior to construction or maintenance projects is critical to ensure the safety of your crew and reducing the potentially costly mistake. Cable locators and wire tracers are specially designed to aid in locating energized and de-energized wires, cable and pipes whether underground or hidden in a wall.

Cable locators are reply on the target having a charge or signal placed on them which is detected by a receiver within the locator, many locators are able to induce a signal onto the line using a transmitter in order to find it. Generally, the target must be metallic in order to conduct the signal, through a sonder or mini-transmitter can be used with plastic pipes. When induce a signal onto a pipe or cable, the transmitter is most commonly connected directly to the line or pipe to be located using signal clamps or clips. The signal will then transmit along the pipe or cable. In areas where there is no access to the line, the transmitter can also induce a signal from above, through the gourd to reach the utility.

Depending upon the application, there is a range of cable locators to be chosen. Some are designed for use for underground lines and pipes while other better suited for the tight confines of a walllikes wire trackers. Cable locators usually include a transmitter and a receiver. A widely used underground cable wire locator is NF-816, which is designed to locate the path of none-energized wirebehind walls or underearth. It can rapidly find the target wire from among plenty of telephone wires or network wires. By comparing the volume of the “tout” sound and the brightness of the signal indicator, you can find the target wire which has the highest volume and brightest indicator.

There are two primary methods of sweeping for lines and pipes with a cable locator: Passive locating involves sweeping an area looking for unknown lines while actively locating searching for a specific line by using either a direct connection or by inducing a signal. When using a cable locator to find underground lines and pipes, the underearth condition has a significant impact on the signal. Lays and camp solids help the signals travel down the line or pipe stronger with less interference than dry soils. So it is necessary to add water to the ground near the transmitter to improve signal strength.

Using Fiber Optic Power Meter to Test Optic Power Level

Fiber optic communication equipment is based on the optical power level between the transmitter and the receiver. The difference of the optical power level between them is the loss of the cabling plant. To measure the power loss of them, an optical power meter is needed to conduct a power loss testing.

fiber optic power meter is typically consist of a solid state detector, signal conditioning circuitry and a digital display of power. To interface to the large variety of fiber optic connectors in use, some form of removable connector adapter is usually provided. The power meter is calibrated at the same wavelength at the source output such as multimode 850 or 1300nm, single mode, 1310, 1490 and/or 1550nm, POF. Meters for POF systems are usually calibrated at 650 and 850nm. The wavelengths used in POF systems.

When performing the test, use the optical power meter adapter to mate to the connector type on the cable. The connectorized reference patch cables must be the same fiber type and size as the cable plant and have connectors compatible to those on the source and cables.

Power meters are calibrated to read in dB reference to one milliwatt of optical power. Some meters of a relative dB scale also, useful for loss measurements since the reference value may be set to 0 dB on the output of the test source. Occasionally, lab meters may also measure in linear units like milliwatts, microwatts and nanowatts.

Optical Power Testing Procedure:
Turn on the power meter to allow time to warm-up.
Set meter to wavelength of the source and “dBm” to measure calibrated optical power.
Clean all connectors and mating adapters.
Attach reference cable or fiber patch cord to source if testing source power or disconnect cable from receiver.
Attach power meter to end of cable and read measured power.

To reduce the measurement uncertainty, you must calibrate the optical power meter according the manufacturers specified intervals. Clean all connectors and remove the meter adapter periodically to clean the adapters and power meter detector. To avoid the stress loss, please don’t bend the fiber optic cables during the testing.

Optic power testing is only one the main part of fiber optic testing. Most test procedures for fiber optic component specifications have been standardized by national and international standards which are converted in procedures for measuring absolute optical power, cable and connector loss and the effects of many environment factors such as temperature, pressure, flexing, etc. Basice fiber optic testing instruments are the fiber optic power meter, optical light source, OTDR and fiber inspection microscope.

Fiber Optic Cleaver Needed In Fiber Optic Cleaving

If you have never done cable splicing and are just beginning to build your fiber optic link, it is recommended to start out with our fiber splicing kit, which is a great starting point for your fiber installation.

Optical fiber fusion splicing always requires that the fiber tips have a smooth end face that is perpendicular to the fiber axis. The cleave quality is very important in determining the fusion splicing loss. This is especially true for specialty fibers such as erbium-doped fibers and dispersion-compensating fibers.

Fiber optic cleaving is the process to scribe and break an optical fiber endface. Fiber optic technicians need some training in order to gain the skills necessary for best possible results.

The goal of fiber cleaving is to produce a mirror like fiber endface for fiber splicing – either fusion splicing or mechanical fiber splicing. Incorrect or pool cleaving techniques will result in lips and hackles which makes good fiber splicing impossible. A bad cleaving usually has to be redone.

The tools needed for fiber cleaving are called fiber optic cleaver or fiber cleave tools. There are two types available on the market: high precision fiber cleaver and field fiber cleaver.

The design of fiber optic cleavers varies among manufacturers such as AFL, Corning, Fujikura or York. But the working principle is the same. Here I describe a typical work flow of optical fiber cleavers.

Step One: Strip the fiber to its cladding size, the standard optical fiber cladding size is 125um. The strip length depends on your application.

Step Two: Clean the fiber with lint-free wipes moistened with isopropyl alcohol.

Step Three: Place the stripped and cleaned bare fiber into the fiber cleaver

Step Four: Scribe the bare fiber with either a cutting wheel or a blade

Step Five: Break the fiber with the built-in mechanism on the cleaver

Step Six: Remove the fiber scrap and put it into a fiber disposal unit

This semi-automated process produces high quality cleaving in minimum steps. It has been used widely in the fiber optic communication industry.

FiberStore provides a complete line of cables, connectors, termination tools, and test equipments for installing and testing fiber optic network. It’s important to make sure you have the proper set of fiber optic tools to working with your fiber optics. At FiberStore, they carry a wide selection of fiber tools, just about every tool needed to successfully install, terminate and test the fiber you’ve installed. Some of the essential fiber tools to have would be a fiber tester, fiber stripper, telephone line tester, fiber optic cleaver, tool kits and other tools.