Fiber-Optic%20Communications

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Fiber-Optic Communications

• James N. Downing

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Chapter 10

• Fiber-Optic Test and Measurement

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10.1 Optical Power Management

• Types of Power Management
• Measuring Component Power Levels
• Measure under steady state conditions
• Cutback method primarily (must cut the fiber)
• Can be made at the manufacturing location
• Can be performed in the field
• Attenuation
• OTDR
• Substitution method

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10.1 Optical Power Management

• Power Measurement Instrumentation
• Power meter measures power.
• Loss set measures attenuation or losses.
• Talk set sends signals to measure attenuation.
• Optical time domain reflectometer measures power
  loss, fault location, and other power-related
  parameters.

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10.2 Optical Wavelength Measurements

• Types of Wavelength Measurements
• Peak wavelength
• Linewidth information
• Channel spacing
• Linearity of channel amplitudes
• Expansion availability
• Security
• Performance

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10.2 Optical Wavelength Measurements

• Optical Spectra Instrumentation
• Optical Spectrum Analyzer
• Measures wavelength and linewidth
• Wavelength Meter
• Accurate wavelength measurements

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10.3 Signal Measurements

• Dispersion and Data Rate Measurements
• Must first change light into electrical signal
• Oscilloscope
• Amplitude as a function of time
• Rise time
• Fall time
• Data rates

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10.3 Signal Measurements

• Noise and Error Measurements
• Eye-pattern analysis
• Measure multiple system noise and error
  parameters by using an oscilloscope
• Spectrum analyzer
• Measures noise and BER levels
• Performs a Fourier transform to measure amplitude
  as a function of frequency
• BER meter
• Digitized eye-pattern system

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10.3 Signal Measurements

• Additional System Test and Measurement
• Phase differences
• Polarization