"In the experiment, two fiber segments of the type similar in length were used PANDA: narrow–band radiation is launched along the fiber, which changes the wavelength at a constant speed, and reflected radiation with different polarization comes with a small difference in wavelengths, - said Konstantin Ovchinnikov, one of the inventors of the technology, a first-year master's student of the Faculty of Physics at PSNIU. – By applying
Fourier transforms to this signal, it is possible to determine exactly what frequency it is, and knowing the laser settings, you can find out the time of passage of light in the fiber and the difference the time between radiations with different polarization".
Initially, scientists set the task of measuring two identical fiber- optic circuits using the method of reflectometry, but during the study they discovered additional parameters. Then it was suggested that this is due to different polarization.
"Later we suggested that in this way it is possible to determine one of the main parameters of the fibers with the preservation of polarization. In the course of the study , difficulties arose with the interpretation of the data of the beat frequencies – comparisons frequencies and interactions of waves with different polarization in different fibers. However , at the moment a theoretical model has been built, which converges with the results of the experiment with a fairly high accuracy," Konstantin said.Ovchinnikov.
"The system developed by the students can replace existing foreign equipment, in particular, American optical reflectometers," says Viktor, professor of the Department of Nanotechnology and Microsystem Engineering at PSNIU Krystop. The reflectometer is used to measure the parameters of fiber-
optical transmission lines, it can also be used to determine the magnitude of birefringence. Perm University students have reworked the methodology
to be able to determine this value, and as a result have found a simpler and cheaper way of measuring. To continue work on this project, a team of young scientists intends to submit their development to a competition "UMNIK-Photonics".
The development of photonics technologies is one of the priority scientific and technological projects of the Perm REC.