Calibrating the unit requires a stable optical source, adjustable optical attenuator, and standard optical power meter. Press the button to adjust the calibration index from +5. EXFO can help save both time and costs with an automated calibration test system that is designed for the verification of power meters, attenuators, sources and optical time-domain reflectometers (OTDRs). This sophisticated device combines advanced photonic technology with user-friendly features to deliver accurate power readings across various. NIST optical fiber power meter calibration services.