JDS Uniphase RM3750 Loss Before the DUT, Reflections Before the DUT, Reflections After the DUT

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Internal Backreflection (for single mode model only, except 980 nm model)
Connector Loss and Backreflection

RM3 SERIES BACKREFLECTION METER

USER’S MANUAL

Loss Before the DUT

￿When a DUT is connected to the RM meter, the loss from connectors before the DUT affects the backreflection reading. Because the light is going out from the RM meter and then returning, it goes through the connectors twice, so the effect of the loss is doubled. If the loss is close to 0.15 dB, its effect is compensated automatically by the meter. If the loss differs substantially from 0.15 dB, follow the measurement procedures described at the end of the Measuring Backreflection section.

Reflections Before the DUT

￿When a device is connected to the RM meter, the reflections from the connectors affect the backreflection reading. The front panel FC/PC connections must have backreflection levels lower than -45 dB for single mode (-25 dB for multi mode), and FC/APC connections must have backreflection levels lower than -60 dB for single mode (-40 dB for multi mode). To ensure that the RM meter automatically compensates for this backreflection, follow the setup procedure described in the Setting Up the Meter for Backreflection Measurements section, and ensure that the backreflections do not change from the time of the setup.

Reflections After the DUT

￿When making a backreflection measurement, the fiber after the DUT must be terminated to eliminate the reflections from the end of the fiber (see the Termination Techniques section). For greatest accuracy when making very low backreflection measurements, terminate near the DUT to eliminate reflections from the fiber itself.

Front Panel Connectors

Follow the maintenance procedure described in the Maintaining the Meter section, to ensure that the internal pigtail connectors are clean and properly connected to the front panel mating sleeve.

Ensure that the loss and backreflection of all the connectors are low and stable, complying with the connector specifications.

To confirm proper operation of the RM meter, terminate the internal cable while using the factory-set BR0 value (BR0 key lamp is off). The backreflection reading must be less than ￿-65 dB.

Long Cables (for single mode model only, except 980 nm model)

Terminate the cables near the devices or connectors being tested in order to eliminate backreflections from the fiber.

10112341 Rev 002

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Contents User’s Manual RM3 Series Backreflection MeterContents Programming Guide Customized Features and Test DataSafety Information Safety Information, Instructions, and SymbolsClass Laser Product Operating the Unit Safety InstructionsBefore Initializing and Operating the Unit RM3 Series Backreflection Meter USER’S Manual Proceeding Safety SymbolsSymbol FDA-CDRH Compliance CSA / IEC Compliance ComplianceCE Compliance RM3 Series Backreflection Meter USER’S Manual General Information General Information and SpecificationsBackreflection Measurements Loss and Power MeasurementsHybrid Jumpers Key FeaturesOutput Port Internal Light SourcesApplications Standard AccessoriesOptional Accessories Parameter Specification Single-mode Multimode SpecificationsFlexcor is a trademark of CorningR Environmental ElectricalPhysical Initial Inspection Getting StartedBefore Initializing and Operating the Unit Storing and Shipping Operating EnvironmentCleaning Connectors Connector Cleaning connector type can vary Powering Up the MeterKey/LED Description Operating and Maintenance InstructionsFront Panel Termination Techniques for Single-mode Fiber except 980 nm Rear PanelTermination Techniques Component FunctionMeasuring Backreflection for Single-mode except 980 nm Backreflection Measurements Setting Up the Meter for Backreflection MeasurementsMeasuring Backreflection Backreflection Accuracy and Range Loss and Power MeasurementsSetting Up the Meter for Loss and Power Measurements Loss and Power Measurements Measuring PowerMeasuring Absolute Power Measuring Relative Power Insertion LossDisplay Description Data Logging Using the Foot PedalMessages and Symbols Power AccuracyStabilizing Calibrating the Meter Power Calibration Adjustment Backreflection Calibration AdjustmentMaintaining the Meter Cleaning the UnitCleaning the Connector Ends Troubleshooting Recharging the BatteryReplacement of Internal Fuses Reflections Before the DUT Front Panel ConnectorsLong Cables for single mode model only, except 980 nm model Loss Before the DUTUp the Meter for Backreflection Other Display Problem SolutionLaser Stability CalibrationRS232 Serial Interface RS232 Interface SpecificationsName Symbol Pin Number Signal Direction Programming GuideCommand Action RS232-GPIB Converter Left Dip SwitchSwitch Setting Meaning Right Dip SwitchRS232 Interface Program Example Programming ExamplesCustomized Features and Test Data
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