DoF Briefing: Challenges of Building Fiber Optic Drones
Writen by: Amith Ravindar, Engineer, Doves Of Freedom
Fiber optic drones, which are controlled via a thin fiber optic cable rather than radio signals, first appeared on the battlefield in Russia’s Kursk Oblast in late 2024. Unjammable due to the kilometers-long cable that controls them, they wreaked havoc on Ukrainian logistics, which largely flowed on one route from the Ukrainian city of Sumy to the Russian city of Sudzha.
Since the withdrawal of Ukrainian forces from Kursk, the use of fiber optic drones has proliferated across the front line on both sides as well as in other theatres, including most recently Iraq.
Below is an image from the video feed of a fiber optic drone about to strike an American Black Hawk at Victory Base in Iraq.
Recently, we at Doves of Freedom built our first fiber optic drones for a drone unit in the Ukrainian armed forces. We had extensive experience building and flying radio-controlled drones, but had never worked with fiber optic drones. However, having heard so much about these new types of drones, we were excited to get our hands on components for them.
The production of fiber optic drones is not simply a challenge for our team, but for Ukraine in general, given the inherent advantages of fiber optic drones.
So, in this article, let’s talk a little bit about the challenges Ukraine faces in building fiber optic drones at scale.
What are fiber optic drones?
Fiber optic drones are drones that are connected by a thin, fiber optic cable, less than 1 mm in diameter, to an operator. This fiber optic cable is stored in a spool that is mounted to the drone itself, and both the commands from the operator and the video from the drone are transmitted through the cable. As the operator flies further and further away from their position, the fiber optic spool uncoils, giving the drone more wire to work with.
Why is building fiber optic drones difficult?
Weight
Fiber optic drones are heavy. Depending on the length of the fiber optic cable in the spool, the spool can weigh as much as 2.5kg. This added weight may mean that the drone requires a more robust frame, larger propellers, and more powerful motors.
Moreover, because weight can increase battery usage, a bigger battery might be required for the drone to travel to and loiter over a target before striking it.
This weight also means that the munition must be smaller to compensate, which requires a more skilled operator to more precisely pilot the heavy drone into its target.
One solution that Ukrainian manufacturers have adopted is to reduce the weight of spools by designing them in such a way that less material must be used to hold the fiber optic coil in place. This is a solution that was already improvised by the Chinese.
Weight Distribution
In addition to the munition and battery, a coil needs to be mounted, usually on the bottom of the drone. This variety of objects that need to be affixed to the drone and that need to stay attached to the drone during the flight can create problems in terms of the stability of the drone.
For stable flight of the drone, the center of gravity of the drone needs to be as close to the center of the drone as possible. In order to achieve this, the position of these different objects on the drone and how they balance each other out needs to be considered carefully.
Furthermore, these need to remain securely attached to the frame through 20km+ of flight, otherwise, they can lead to vibrations and instability in the drone’s flight.
This challenge of keeping the drone balanced is compounded by the fact that as the fiber optic cable unwinds from the drone during flight, it actually reduces the weight of the spool itself, altering the weight distribution of the drone.
Accordingly, Ukrainian manufacturers that produce both the spools and drones custom-designed to work with these spools have been more successful at creating performant fiber optic drones. These are distributed to units as full “kits.”
Ground Station
Ground stations are required to connect a controller and headset or monitor to a fiber optic spool, so that an operator can fly a drone. This is more of a logistical issue, but it seems like different types of fiber optic drones all require different ground station modules, each of which can be expensive.
This is due to differences in the physical characteristics of the fiber optic cable, as well as the type of signal transmitted across the cable, which must be converted to electrical signals at the ground station.
Particularly if a unit or volunteer organization is working with spools from different organizations, this can be both inconvenient and expensive.
However, Ukraine has very recently made efforts to create a common ground station that can replace the array of ground stations that would normally be present at drone positions.
Cost
One of the reasons we probably didn’t get a request for fiber optic drones earlier, despite fiber optic drones already being used on the battlefield throughout 2025, is the cost. While a typical radio-controlled drone costs around $500, a fiber optic drone can cost as much as $1200, or even more, depending on the cost of fiber optic cable.
Despite changes that need to be made to the design of the drone itself, the biggest expense still remains the fiber optic spool itself.
Fiber optic drones tend to use specialized fiber optic cable that is thinner, lighter, and more flexible than the fiber optic cable used in telecommunications. Moreover, the raw materials used to make fiber optic cable itself are in heavy demand by telecommunications companies, particularly for use in data centers
Once Ukrainian manufacturers acquire this cable, it must be wound into coils in an extremely precise process that requires manufacturers to build custom winding machines.
All of these factors contribute to the cost of fiber optic spools, the economic factors notwithstanding.
There has been an explosion in demand in both Russia and Ukraine for fiber optic cable that only China can produce at scale. Even in increasing their capability to wind fiber optic, both Ukrainian and Russian manufacturers have had to work directly with Chinese manufacturers.
According to Russian sources, the price of fiber optic cable per kilometer tripled over the course of last year to 40 yuan ($5.85) per kilometer. According to Ukrainian sources, in 2026, the price had already risen to as much as $20 per kilometer and currently hovers around $45 per kilometer at the time of writing.
If we consider the fact that Ukraine produces around 50,000 fiber optic drones a month and that each contains an average of 20km of fiber optic cable, the scale of the problem becomes clear.
In a weird way, Ukraine’s destruction of Russia’s only functional fiber optic plant in May of 2025, which produced 4,000,000 kms of fiber optic cable annually, or 30% to 40% of Russia’s total fiber optic consumption annually, has exacerbated this problem. This is because now both Russia and Ukraine are competing for access to the same Chinese fiber optic plants, with Russia having the diplomatic upper hand.
Although in the long-term, complete Russian dependence on China for supplies of fiber optic cable might not be a bad thing for Ukraine, particularly as Ukraine is able to gain access to alternative suppliers in Europe and India.
Our Experience
In some ways, it was actually easier than building radio-controlled FPV drones because we had none of the complications associated with adding and configuring the VTX (for video transmission) and ELRS chip (for receiving commands from the controller).
In place of these, we had a simple cord that would connect to the drone’s fiber optic spool. Through the spool, the drone would be able to both receive commands from the operators at a remote ground station and send back a video feed from the camera.
Probably the main difference was in the configuration of the drone, given that the fairly large spool of fiber optic cable had to be mounted underneath the drone. This meant that the battery was actually mounted at the front of the drone, which makes sense from a balance perspective. The mounting was largely done via 3D printed components that we attached to the drone.
Once deployed, the munition would be placed at the top of the drone to be initiated by the operator or the pigtails mounted at the front of the drone.
Other than that, the flight controller and ESC that are the brains of the drone were the same as what we would use for a radio-controlled FPV drone along with the rest of the other components.
In terms of handling some of the issues like balance, configuration, and weight, we mitigated these issues by buying a kit of components that had already been proven to successfully function together from a Ukraine-based company called Bora Industries.
At the moment, we’re currently running our biggest ever fundraiser to support the International Battalion of 1st Azov Corps with a new batch of fiber-optic FPV drones, which you can support here.
Based on the lessons and feedback from our first batch of fiber optic drones, we will soon begin buying parts for and assembling our newest batch. Hopefully, in the future, we’ll be able to put out a “Lessons Learned” type article for this batch.
Just so you know, Doves of Freedom is a registered charity organization in both Ukraine and Canada and staffed by Americans, Brits, and Canadians who have been supporting the Ukrainian military both as members of the Armed Forces of Ukraine and as civilians since the beginning of the full-scale invasion in 2022. We supply frontline units with both radio-controlled and fiber optic FPV drones, free of charge.
You can also follow us on Instagram here to see what we’re up to.
Thanks for reading!
Amith