What are the detector materials in power meters?
-Silicon for shorter wavelengths.
-Germanium or indium gallium arsenide for longer wavelengths.
Power meter calibration
-Wavelengths must follow NIST for USA standards. Some wavelengths are more sensitive to the device than others for testing
-Must be recalibrated every year since they are known to drift.
Insertion loss test
-When a power meter and a light source are used to measure the loss inside of a fiber.
- Can have 1, 2, or 3 jumpers.
What causes OTDR uncertainty in measurements?
-Modal dispersion
-Pulse width
-Deadzones (EDZ&ADZ)
-Backscatter coefficient variability
-IOR error
-Step loss & Reflective loss
-Signal to Noise ratio
Gainer (OTDR)
Whenever there is a random increase on the read of backscattered light.
Splice loss error
-Core misalignment
-Angular misalignment
-MFD diameter
-Backscatter coefficient mismatch
-Poor cleave quality
-Gas bubbles in the splice
-Arc callibration error
-Fiber bend in splice
Connector loss error
-Endface geometry errors
-Contamination errors
-Ferrule misalignment
-Air gaps
-Endface damage
-Mode-Field diameter mismatch
-Poor installation
-Connector mismatch
How do you test for PMD
-Interferometric method
-Jones Matrix Eigenanalysis
-Fixed analyzer or “scrambling method.”
Optical reflectance testing
-Test that measures how much light is reflected to the source.
-OTDR and ORL
Types of OTDR testing
-Single-Ended/Oneway
-Double-Ended/Two-way
-Bidirectional
-Backscatter-based
-Event/Insertion loss testing
-Live fiber testing
-Encircled/Backloop testing
Information displayed on an OTDR
-The trace.
-Event table with type, location, number, and types of loss.
-Reflectance in the fiber.
-Slope of attenuation coefficient.
-Measurements & Settings (ex., pulse width, dynamic range, averaging time)
OTDR measurement parameters
-Range
-Wavelength
-Pulse width
-Averaging
-NVP or Index of refraction
