With the massive use of fiber-optic drones, Russian and Ukrainian experts are looking for a solution that would help protect against them. Wired communications have made attack drones and their pilots completely invulnerable to electronic warfare and reconnaissance.

The research in this area has been overgrown with theories and myths in a short period of time, but the tests presented below have debunked some of them and offer one of the first working solutions to combat enemy UAVs.

Militarnyi is cautious about disclosing Ukrainian developments in the technological sphere, but with the publication of relevant materials by hostile resources, any secrecy loses its meaning.

Recently, Russian telegram channels published a study of a hypothesis on finding fiber-optic drone control points by laser-illuminated wires. Theoretically, in the dark, the cable irradiated in this way would become a “path” to the other end with a UAV control point.

For the study, the Russians used a laser flaw detector with the VFL function, which is designed to find breaks in network fiber-optic cables. The laser, fired along the cable, perfectly highlights the places of damage, breaks or other areas with high signal loss.

To confirm or refute the hypothesis, the researchers simulated a real situation by laying a three-kilometer-long cable with a conventional fiber-optic drone. The drone simulated a real flight scenario, performing maneuvers and turns. From the point of the cliff where the allegedly used drone was located, a conventional OTDR with VFL function was connected.

The test showed that visually at night, the cable connected to the flaw detector does emit light with a low intensity. However, this was not enough for a drone with a daytime camera to track the direction. DJI Mavic 3T, a popular drone among the military, does not see such a cable through either the TV or thermal imaging channels.

Instead, at night, this cable glows quite brightly in the infrared spectrum. It is perfectly visible with a passive night vision device or a drone such as Autel Max 4N with an IR camera.

Militarnyi contacted the specialists of DeepStrikeTech, a Ukrainian miltech company that develops and researches the combat use of drones with fiber-optic communication systems, to verify the results of enemy tests.

Ukrainian researchers studied the possibility of using lasers to illuminate fiber-optic cables and contacted a scientific institution. There, they obtained similar results when using equipment for illumination and break detection. However, third-party laser illumination of the cables did not work.

The developers also studied the possibility of detecting the glare of a working fiber-optic cable when a drone transmits signals, but this hypothesis proved to be unworkable due to the specific radiation spectrum.

“In my opinion, you can only detect fiber optics by physically seeing them. We contacted a scientific institution and could not find any solutions, because the spectrum in which the signal is transmitted is invisible to the human eye or to special cameras. We even shone not at the fiber, but at the connector itself and the core,” says Viktor, a representative of DeepStrikeTech.

Given the results, we can confidently say that in theory, it is possible to search for enemy pilots using illuminated fiber-optic cables. However, this requires a number of conditions to be met:

• The specialists must find the necessary cable before the enemy pilots change their position;
• the search is possible only at night and with the necessary equipment and drones;
• the cable must be intact, i.e., without any breaks that would interfere with the laser beam.

Experts who have studied this method say that to illuminate a cable, you need to connect a flaw detector to it directly. To do this, you need to properly strip the cable using a special fiber optic stripper, and then connect the fast connector. The process takes about 10-15 minutes, but in the field, it may take a little longer.

Given that the operators of fiber-optic drones with daytime cameras leave their position at night and change it the next day, this tactic is hardly effective. However, it may be useful in the fight against nighttime drone operators.

It is also worth mentioning a somewhat related episode of the Russian-Ukrainian war, when the operators of the 15th Kara-Dah Brigade discovered a large cluster of fiber-optic cables by the glare of the sun and were able to track the location of enemy pilots. As a result, the enemy control center was immediately attacked.

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— Karna La Vera (@Karna13377) February 18, 2025

According to Militarnyi’s interlocutors, such cases are rare and their probability is already close to zero: the military has been purchasing fiber-optics with a matte black or green covering for a long time.