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  • Press Release from EXFO
  • Featured Product: Introducing...
    the EXFO AXS-110 Series
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    Will It Shoot?
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    Featured Press Release From EXFO Back to Top

    EXFO Introduces OTDR Series for Access and Enterprise Network Testing

    * High-performance OTDR model characterizes both multimode and singlemode fiber

    QUEBEC CITY, CANADA, March 13, 2007 — EXFO Electro-Optical Engineering Inc. (NASDAQ: EXFO, TSX: EXF) announced today the introduction of the AXS-110 OTDR for access and enterprise network testing.

    This lightweight, handheld OTDR, which builds on EXFO’s leading technology and market share in optical time-domain reflectometry, has been designed with the new reality of field technicians in mind. The new AXS-110 OTDR is specifically intended for technicians who must transition from copper to fiber testing with the benefit of little or no training, thus making its high performance and simplicity key benefits.

    As part of the AXS-100 OTDR Series, it boasts an unmatched high resolution (event dead zone) of 0.8 meters for easy identification and characterization of events, which is critical for characterizing short links as there are numerous connection points along them. As well, a single touch of the FasTrace button enables the capture of OTDR traces for maximum simplicity and user-friendliness...

    Read More At >>

    Featured Product: EXFO Access 110 Back to Top
    Order it now! Get Specifications See it on the web Introducing the AXS110 Series

    Model Descriptions & Pricing

    Model Description and Options Price
    AXS-110-QUAD Combining singlemode and multimode capabilities for enterprise, campus and access networks, this model offers the 850, 1300, 1310 and 1550 nm wavelengths, with respective dynamic ranges of 24, 25, 32 and 30 dB. $10,000
    AXS-110-SM Ideal for FTTx/access and CATV testing, the singlemode model offers the 1310 and 1550 nm wavelengths, with respective dynamic ranges of 32 and 30 dB. $7,500
    AXS-110-MM Optimized for enterprise testing on both 50 and 62.5 µm multimode fiber, the multimode model offers the 850 and 1300 nm wavelengths, with respective dynamic ranges of 24 and 25 dB. $7,500
    Monthly Tidbits Back to Top
    Help us build a community! Do you have a question or concern, solution or answer, lesson learned or useful resource that you would like to share with the community? E-mail your question or tidbit to and we will feature your comments in future mailings. Get credit and gain exposure by including your name and a link to your company or personal business.

    Tidbit #1: How Far Will It Shoot?

    "Many of our customers ask us about maximum distances and signal losses when on the market for an OTDR. The fact of the matter is that there is no way to know all the variables as these measurements are dependant on a number of installation-specific factors such as type of cable used (singlemode/multimode/combo), condition of the cable, number of splices and connectors and other dispersive losses. I've found the table and equations below (drawn from a technology overview report by IMC Networks) to be useful guides for calculating both maximum signal loss across a piece of pre-existing fiber as well as the maximum fiber distance given known budget and loss variables. However, I always encourage people to be aware that these are only estimates and not guarantees."

    -- Matt Aigeldinger
    Director of Marketing and Sales

    Fiber Loss Table

    The numbers listed are averages typical of new fiber. When calculating using these numbers, take them to be more of a "best case" estimate.

    Wavelength/Mode Fiber Core Diameter Attenuation per Kilometer Attenuation per Splice Attenuation per Connector Modal Bandwidth (MHz-km)
    850 nm/multimode 50 µm 3.75 0.1 dB 0.75 dB 185
    850 nm/multimode 62.5/125 µm 3.0 dB 0.1 dB 0.75 dB 185
    1300 nm/multimode 62.5/125 µm 0.7 dB 0.1 dB 0.75 dB 500
    1310 nm/singlemode 9 µm 0.35 dB 0.1 dB 0.75 dB N/A
    1550 nm/singlemode 9 µm 0.22 dB 0.1 dB 0.75 dB N/A

    Calculating Fiber Loss

    Maximum signal loss is simply the sum of all the worst-case variables within your fiber segment. Once again, the values in the table above are averages for new fiber so be sure to include at least 3 dB of loss as a safety buffer to account for fiber aging, poor splices, temperature/humidity etc.

    Total Signal Loss Equation
    Loss = (Fiber Attenuation x km)
    + (Splice Attenuation x # of splices)
    + (Connector Attenuation x # of connectors)
    + (Safety Margin)

    = Total Loss

    As an example, suppose you want to determine the average losses on a run of 10 km 1310 single-mode fiber with one splice. Let's include connector losses and a 3dB safety margin as well:

    Example Problem
    Loss = (0.35 dB/km x 10 km) = 3.5 dB
    + (0.1 dB/splice x 1 splice) = 0.1 dB
    + (0.75 dB/connector x 2 connectors) = 1.5 dB
    + (3 dB) = 3 dB

    = 8.1 dB Total Loss

    Calculating Budget and Fiber Distances

    The first step in calculating distance is to calculate the power budget. Power budget is found by subtracting the receive sensitivity (the minimum energy required for the fiber receiver to detect a signal) expressed in dBm from the launch power (the amplitude/energy of the light as it leaves the transmitter) also expressed in dBm to yield the power budget in dB.

    As a quick example, suppose you are connecting a fiber switch with a -17 dBm minimum launch power to a media converter with a worst case receive sensitivity of 30 dBm:

    Power Budget = (Launch Power) - (Receive Sensitivity)  
    Power Budget = (-17 dBm) - (-30 dBm) = 13 dB

    Then losses from splices, connectors and the safety margin are subtracted from the power budget to get the net power budget, also expressed in dB. This number is finally divided by the maximum loss per km specified by your fiber.

    The example below demonstrates maximum fiber distance using the numbers from all previous examples with fiber that is specified at a loss not to exceed 0.3 dB/km:

    Example Problem
    Power budget = 13 dB
    Losses from splices = -0.1 dB
    Losses from connectors = -1.5 dB
    Safety Margin = -3 dB

    Net Power Budget = 8.4 dB
    Total Distance
    (8.4 dB)/(0.3 dB/km) = 28 km

    A Brief Word On Modal Dispersion

    When calculating distances for multi-mode fiber, it is important to also include losses from modal dispersion, an uneven dispersion of light occurring in multi-mode fiber that can create a form of jitter as data traverses the cable.

    Since modal dispersion is dependant on the data rate, use the following example as a reference for how to calculate maximum distance. Assume you are using 850 nm multi-mode fiber with 100 Mbps Fast Ethernet (actual bit rate = 125 Mbps).

    Distance = (185 MHz-km)

    = >1.5 km
    (125 MHz)

    Note: The length is not typical of Monthly Tidbit responses. Though there are no limitations, 3 paragraphs or less is usually desired.

    Solve Puzzle And Win A Prize! Back to Top

    Solve this month's WORD PUZZLE and enter a drawing to win a FREE VEST!* Unscramble the following word and simply e-mail the solution to with your address and preferred size (L, XL or XXL).


    *The number of monthly winners is limited to the quantity of available prizes. Due to international shipping costs, participants outside the U.S. will receive their prize along with their next order from