Abstract: A light pulse generator is connected with one end of an optical fiber which selectively emits light pulses of a plurality of wavelengths to the optical fiber. A photodetector outputs a signal corresponding to the strength of the light reflected from the optical fiber. A storage unit stores the signal output from the photodetector for each wavelength. A processor determines the position and characteristic of an event based on the waveform data for each wavelength stored in the storage device. A display device has first and second display areas. A display controller allows the first display area to display the waveform data for each wavelength stored in the storage unit in a discriminable manner, and allows the second display area to display a list of positions and characteristics of events for each wavelength determined by the processor.

Abstract: A measurement data display apparatus is provided which has an input section, a display, and a control section. The display displays a main screen showing fundamental measurement data of a measured object. In addition, responsive to an operation of a first key of the input section, the control section pops up on the main screen a secondary screen which simultaneously includes a plurality of large item menus relating to additional measurement data of the measured object, and a plurality of small item menus corresponding to each of the plurality of large item menus. Each of the plurality of small item menus are displayed at a position corresponding to each of a plurality of function keys of the input section, and the plurality of large item menus are enabled to be selected by operating a second key of the input section.

Abstract: An optical time domain reflectometer receives a return light of an optical pulse incident on a measurement target optical fiber formed out of a plurality of optical fibers coupled in series, and measures the splice loss, return loss and unit length loss of the measurement target optical fiber. A maximum value detector detects a maximum value due to an absolute value for the splice loss and maximum values for the return loss and the unit length loss of the measurement target optical fiber, respectively, in response to the return light. A display unit displays the maximum value due to the absolute value for the splice loss and the maximum values for the return loss and the unit length loss according to items of the splice loss, the return loss and the unit length loss based on output from the maximum value detector.

Abstract: First to fourth initial data memories 31a to 31d prestore initial data R obtained when a reference optical fiber 22 having a predetermined length was previously measured, and initial data Pa to Pc obtained when a to-be-monitored optical fiber was previously measured. A first arithmetic unit 33 finds a difference .alpha. between measurement data R' obtained when the reference optical fiber 22 is newly measured and the initial data R as a first drift amount representing a variation in characteristics of the OTDR itself. A second arithmetic unit 34 finds a difference .beta. between measurement data P' obtained when the to-be-monitored optical fiber 1 is newly measured and the initial data of the to-be-monitored optical fiber as a second drift amount representing a variation in characteristics of the OTDR itself and characteristics of the to-be-monitored optical fiber 1. A third arithmetic unit 35 finds, from a difference between .beta. and .alpha., a real characteristic variation amount .gamma.