Optical frequency domain reflectometry
The optical Frequenzbereichsreflektometrie , also known under the English name O ptical F requency D omain R eflectometry short OFDR is a process for the identification and analysis of run lengths and reflection characteristics of electromagnetic waves and signals in the wavelength range of the light . It is related to optical time domain reflectometry (OTDR).
OFDR does not work in the time domain like OTDR technology, but in the frequency domain . With the OFDR method, a statement is made about the local temperature profile if the backscatter signal detected during the entire measurement time is measured as a function of frequency and thus in a complex manner (complex transfer function) and then Fourier transformed .
The main advantages of OFDR technology are the quasi continuous wave operation of the laser and the narrow-band detection of the optical backscatter signal, which results in a significantly higher signal-to-noise ratio than with pulse technology. This technical advantage enables the use of inexpensive semiconductor laser diodes and the use of cheaper electronic assemblies for signal averaging. On the other hand, there is the technically difficult measurement of the scattered light (complex measurement according to amount and phase) and signal processing that is complex due to the FFT calculation with higher linearity requirements of the electronic assemblies.
See also
Web links
- Optical code division multiplexing processes in sensor technology p. 10 ff. (Accessed on March 12, 2018)
- METHOD AND MEASURING DEVICE FOR SPATIAL DISTRIBUTED AND / OR DISTANT MEASUREMENT OF PHYSICAL VALUES (accessed on March 16, 2018)
- Optical Frequency Domain Reflectometry (accessed March 16, 2018)
- OPTICAL FREQUENCY DOMAIN REFLECTOMETER FOR CHARACTERIZATION OF OPTICAL NETWORKS AND DEVICES (accessed March 16, 2018)