ETU “LETI” Scientists’ Research to Improve the Efficiency of Optical Radio Monitoring Systems of the Future

ETU “LETI” Scientists’ Research to Improve the Efficiency of Optical Radio Monitoring Systems of the Future

A mathematical model presented by ETU “LETI” specialists makes it possible to identify the limitations in the use of optical processors. Such processors are considered to be the basis for next-generation radio monitoring systems.

12.05.2024 102

An important element of radio systems for various purposes (communication, monitoring, location, etc.) is special digital processors. These devices serve to real-time processing of digitized radio signals. They are characterized by relatively high performance and the ability to carry out various computations. In addition, their mass production uses widespread components.

However, the world is facing an ever-increasing need to transmit bigger volumes of information with a higher speed. This fact forces the scientists to look for ways to switch radio systems to ultra-high frequencies (UHF). At the same time, when it comes to operating in the microwave range, digital processors have certain physical limitations. Upgrading them allows us to overcome these limitations but only to some extent (this also leads to processor design becoming more complex and the cost increasing). Therefore, researchers are working to develop computing devices based on other physical principles. 

Optical processors are one of the promising alternatives to digital processors. Since these devices use optical frequency range signals, they have higher performance and energy efficiency while being smaller than digital ones. However today most examples of optical processors are single laboratory specimens. Their mass production requires that a theoretical base, production technology and component base be developed.

“Our department has manufactured an optical processor for a direction finder; it’s a device which allows you to determine the location of objects. Taking into account its principle of operation, this device can also act as a spectrum analyzer, which is a device for radio monitoring of signals in a wide frequency range. This device is very useful when you need to conduct a real-time reconnaissance of the area, for example, at the airport.”

Leonid Aronov, Senior Lecturer at the Department of Theoretical Foundations of Radio Engineering at ETU “LETI”

ETU “LETI” specialists aimed to complete the task without changing the design of the processor, since this could make the device more complicated, and, therefore, bigger and more expensive. Thus, it was necessary to analyze the capabilities of the processor's optical circuit and select a reference signal that allows analyzing a wide range of frequencies. To do this, ETU “LETI” scientists have developed a new mathematical model.

As a result, the scientists have discovered two problems typically occurring when an optical processor operates in the spectrum analyzer mode. First, it turned out that the old processor algorithms could detect signals only at certain frequencies, and between these frequencies, the information was lost. The solution to this problem was to use a reference signal of a special structure.  Second, optical processors are noticeably affected by photonic noise. This sometimes leads to some signals being distorted or missed.

 “There are several ways to solve the second problem. For example, we can use various optical processors in parallel to increase the dynamic range of a radio monitoring system. Although, this does not remove the limitation associated with the inevitable fundamental photonic noise. There is another approach – to use a more advanced component base for an optical processor and develop a new one. However, this solution is still at the stage of laboratory models. Nevertheless, this task can be solved one way or another in the future as radio engineering systems switch to higher frequencies,” explains Leonid Aronov.

The results of the study are published in the scientific journal Journal of the Russian Universities. Radioelectronics (Izvestiya Vysshikh Uchebnykh Zavedenii Rossii. Radioelektronika) and are also set out in the PhD thesis of Leonid Aronov, which he successfully defended in 2023.

Anastasia Mustafina, a 4th-year student of the Faculty of Humanities of ETU "LETI"