Chapter 10 Optical fiber measuring instruments and testing single-mode fiber networks Schematic illustration of the main parts of an OTDR Simplified graph from an OTDR OTDR curve and how it is used for distance measurement OTDR curve and its use in attenuation measurement Two – point method The many-point method Three graphs with different pulse width showing “dead zone” and noise caused by the pulse width. The time set to the left, is only to give an indication of the time interval commonly used. Block diagram of a stabilized light source with laser diode module The connection of a stabilized light source and power meter for determining the reference value Setup for measuring the cable attenuation of an operational installation Measuring connector and splice loss Pinpointing the fault