• Optimize the input polarization into the PMF by trying to movethe blue spot into the center of the display which indicates theoptimum input polarization.6.4.3 Application: PER/PMF Crosstalk (Using a single A1210 Thermal Cycling Unit)Use this application for crosstalk measurements of polarization maintain-ing fibers (PMF) using a laser source at a fixed wavelength and an A1210to automatically heat up and cool down the PMF.Connect the instrument and the PMF according to the following setup:FixedWavelengthLaser SourcePER AnalyzerLaser Output Polarimeter Input(SMF or PMF)Personal ComputerUSBA1200PMFPaddlesGPIBGPIB(optional)ExpansionUSB12V PowerSupplyA1210Thermal Cycling UnitTo optimize the PER inside the PMF follow these steps:• Setup your device so that coherent light is guided through the PMF(e.g. turn on your laser diode or connect a tunable laser source tothe PMF).• Start the PER-application by double-clicking it.• If the Thermal Cycling Unit is detected, the heater 1 should appearas ”off” in the ”Fiber Heater Status” area.• Enter the correct wavelength of the laser source• Click on ”PER (Heater)”• The A1210 is starting the temperature cycle by heating up the PMF(LED=red) and then cooling down the PMF again (LED=green).Then the device is turned off (LED=off).• The number displayed on the screen is the current PER.• Once a PER value is stable, the software switches to the ”PERLive” mode for realtime alignment.• Now the current PER is measured in realtime based on the recentlystored reference.• Optimize the input polarization into the PMF by trying to movethe blue spot into the center of the display which indicates theoptimum input polarization.• If you think you have reached the optimum, you can repeat themeasurement by clicking on ”PER (Heater)” again.52 A1XXX/A2XXX/A3XXX User Guide
