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      Certifying Optical Power Levels at PON Distribution Cabinets

      Power distribution can impact service activation

      PON networks utilize Point-to-Multi-Point fiber topology and an OLT can support up to 128 subscribers. A distribution cabinet can house multiple OLTs in which each can have numerous fiber output ports. As part of the PON construction process, the construction crew needs to verify every port is receiving the required power levels before proceeding to build the next section/feed of the optical distribution network (ODN). Centralized and distributed PON networks are built with splitters that distribute power equally.  An ODN can have 1 to 3 splitters (cascade) to get services to subscribers.

      The OTDR is a must-have tool when working with fiber optics. Most OTDR are used to perform single-ended fiber characterization to qualify and identify events and fault locations.  In addition, many OTDRs have VFL, OLS and broadband OPM (BB-OPM) options. The VeEX FX150+ OTDR has a unique application, the fiber's Primary Flexibility Point (PFP) Splitter Power test mode, that allows outside plant technicians to use the built-in BB-OPM to certify that every F1/FDP fiber distribution point/cabinet splitter output port has adequate downstream power level to reach F2/F3/subscriber, to guarantee good service.  

      PON distribution (splitter) cabinet being tested

      For older FX150 or FX150+ OTDRs, their OPM can be re-calibrated to add 1577 nm or use the 1550 nm wavelengths, with measurement compensation, to correctly check the F1/F2 power levels.

      Using FX150+ PFP Splitter Power

      The PFP Splitter Power test application can be accessed via the Fiber menu.

      Quick Guide

      Clean and inspect all the optical connectors, before making any connections between the test set and distribution panel.

      1. Close OPM dust cap and set the ZERO reference for the OPM.
      2. Set the Pass/Fail (P/F) threshold to the minimum acceptable power level.
      3. Set desired wavelength (λ) to 1490nm, 1550nm or 1577nm.
      4. Enter the number of strands in cabinet to be tested.
      5. Connect a clean patch cord to the Port, to view its optical signal power level in dBm.
      6. Tap on Acquire to save the signal level value and advance to the next fiber port cell to test.
      7. Use the Down arrow button or Up arrow button buttons to skip ports/cells on the screen or to go back to re-test bad strands.
      8. Repeat steps 4-7 until all strands are tested.
      9. Tap on Stop/Save to save results and end test.

      Note: Fiber Distribution Cabinets go by different names and acronyms, including PFP for Primary Flexibility Point, Process Fiber Terminal, FDP Fiber Distribution Point, Fiber Distribution Terminal, Fiber Cabinet, Splitter Cabinet, Street Cabinet, etc.

      Related Test Solutions

      • FX150+ - Mini OTDR for FTTx, PON and Metro Fiber Networks