An OTDR in use An optical time-domain reflectometer ( OTDR) is an instrument used to characterize an. An OTDR is the optical equivalent of an electronic. It injects a series of optical pulses into the fiber under test and extracts, from the same end of the fiber, that is scattered () or reflected back from points along the fiber. The scattered or reflected light that is gathered back is used to characterize the optical fiber. This is equivalent to the way that an electronic time-domain meter measures reflections caused by changes in the of the cable under test. The strength of the return pulses is measured and integrated as a function of, and plotted as a function of fiber length.
Software driven controls. The OTDR injects an accurately timed light pulse into the fiber and the optical detector observes the small proportion of light that is reflected backwards (backscatter) as the forward propagating pulse travels along the fiber being measured. The amount of light that is backscattered is a tiny fraction of the input pulse, typically less than one millionth (. Simulate and optimize optical devices by combining the COMSOL Multiphysics® software and the add-on Wave Optics Module. Learn more here. For Honor. Light Ray Free Downloads. Our 'Optical Reflection Software' download list customized for people who search for Light Ray. Program to compute optical properties of multilayer. Related Software. FreeSnell and SimRoof were originally written to support. Zemax delivers design software, training, and support services that set the highest standards for the optical and illumination industries.
Contents • • • • • Reliability and quality of OTDR equipment [ ] The reliability and quality of an OTDR is based on its accuracy, measurement range, ability to resolve and measure closely spaced events, measurement speed, and ability to perform satisfactorily under various environmental extremes and after various types of physical abuse. The instrument is also judged on the basis of its cost, features provided, size, weight, and ease of use. Some of the terms often used in specifying the quality of an OTDR are as follows: Accuracy: Defined as the correctness of the measurement i.e., the difference between the measured value and the true value of the event being measured. Measurement range: Defined as the maximum attenuation that can be placed between the instrument and the event being measured, for which the instrument will still be able to measure the event within acceptable accuracy limits.
Instrument resolution: Is a measure of how close two events can be spaced and still be recognized as two separate events. The duration of the measurement pulse and the data sampling interval create a resolution limitation for OTDRs.
The shorter the pulse duration and the shorter the data sampling interval, the better the instrument resolution, but the shorter the measurement range. Resolution is also often limited when powerful reflections return to the OTDR and temporarily overload the detector.
When this occurs, some time is required before the instrument can resolve a second fiber event. Some OTDR manufacturers use a “masking” procedure to improve resolution. The procedure shields or “masks” the detector from high-power fiber reflections, preventing detector overload and eliminating the need for detector recovery.
Industry requirements for the reliability and quality of OTDRs are specified in the Generic Requirements for Optical Time Domain Reflectometer (OTDR) Type Equipment. Types of OTDR-like test equipment [ ] The common types of OTDR-like test equipment are: • Full-feature OTDR: Full-feature OTDRs are traditional, optical time domain reflectometers. They are feature-rich and usually larger, heavier, and less portable than either the hand-held OTDR or the fiber break locator. Despite being characterized as large, their size and weight is only a fraction of that of early generation OTDRs. Often a full-feature OTDR has a main frame that can be fitted with multi-function plug-in units to perform many fiber measurement tasks. Larger color displays are common.