This document discusses optical fiber detectors. It describes the basic types of optical fiber detectors including PN photodiodes, PIN photodiodes, and avalanche photodiodes. It explains how each detector works by absorbing photons and generating electron-hole pairs that produce a photocurrent. The document also discusses parameters that characterize detector performance such as responsivity, quantum efficiency, and detectivity. Finally, it outlines different types of fiber sensors including intrinsic sensors like microbend and flow sensors, and extrinsic sensors for applications like level detection, pressure sensing, temperature measurement, and velocity measurement.

10. PIN Photodiode

14. AVALANCHE PHOTODIODE PROCESSS Figure 4 — APD

18. PHASE FIBER SENSOR

19. POLARIZATION FIBER SENSOR

20. FIBER MICROBENDING INTIRINSIC SENSOR

21. INTRINSIC OPTICAL FIBER FLOW METER

22. EXTRINSIC FIBER OPTICAL FLUID LEVEL DETECTOR

23. PHOTO ELASTIC PRESSURE SENSOR

24. FLUOROOPTIC TEMPERATURE SENSOR

25. FIBER LASER DOPPLER VELOCIMETER

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