As unmanned aerial systems continue to evolve, there is one category that is attracting increasing interest, especially in defense and surveillance circles: the fiber optic drone. While most people are familiar with wireless drones that rely on radio frequency links for control and data, fiber optic tethered drones take a completely different approach by replacing wireless RF communications with a physical fiber optic connection.
At its core, a fiber optic drone is an unmanned aerial vehicle (UAV) that remains connected to its ground operator via a thin ribbon of optical fiber. These fibers are not used to deliver power, as is common with some other tethered devices, but are used specifically for communications. Control, telemetry and high-bandwidth video signals are transmitted using optical signals rather than radio waves. As a result, the drone is controlled through direct, closed communication with its operator.
How the technical setup works
The hallmark of a tethered fiber optic drone system is easy to spot – the on-board fiber canister connected to the drone. Inside this compact case is a finely wound spool of bare optical fiber. As the drone rises and moves through its flight path, fibers continuously flow out of the can in real time. Because the fibers are wound on the spool under controlled tension, they remain on the spool inside the case until the stronger tension of the drone’s movement initiates propulsion, ensuring reliable signal transmission without interfering with flight dynamics.
On the ground, fibers connect to the operator’s control and monitoring equipment. Because the fiber itself carries the data stream, there is no dependence on antennas, transmitters, or spectrum availability. The result is a deterministic communications link that works in the same way as a direct cable connection, rather than a wireless connection.
Regarding the optical fiber itself, it is usually uncoated or uncabbed, and is referred to as bare optical fiber. While manufactured with a small layer of protective coating, a standard bare optical fiber is typically 250 µm or 200 µm in diameter. While they can be used as is for tethered drone connectors, the fiber may include an additional protective layer to increase durability, resulting in a larger diameter, such as 400 µm. In some of the latest rope innovations, protective materials such as Kevlar are incorporated into the coating for added durability. To achieve communication over distances beyond a few hundred metres, single-mode optical fiber is used due to its long-range transmission characteristics.
How do fiber optic drones differ from wireless drones?
Wireless drones rely on radio frequency signals that propagate through the air. While this allows for longer-term and more versatile operation, it also presents weaknesses. RF signals can be detected, jammed, intercepted/hacked, or degraded due to terrain and environmental conditions. In contrast, communications sent over a fiber optic tether are not detected using radio frequency identification systems, cannot be intercepted without physically accessing the fibers themselves, and are immune to electromagnetic interference. Similar to why hard-wired CCTV systems are still the solution of choice for surveillance applications when hacking and malicious radio interference are a concern, fiber optic drone communications provide similar benefits.
This physical fiber optic connection essentially meets the operator’s needs with added benefits. Data rates are becoming more consistent and predictable, high-quality video feeds and instant control are supported, and optical fiber delivers consistently low-latency performance. From a control perspective, the operator/pilot enjoys stable, responsive communication regardless of RF congestion or electronic countermeasures.
Basic benefits of physical fiber connection
Simple and straightforward, the most important advantage of fiber optic tether is security. The optical fiber does not radiate energy, meaning the drone is effectively silent from an RF detection standpoint, which is often the main focus of air defense and detection systems. This makes them particularly valuable for contested, battlefield and covert use, where mitigating drone detection or interference is essential.
Reliability is another major benefit. Fiber connections are not affected by weather, multipath fading, or spectrum congestion. This results in consistent connectivity and high-quality data delivery, even in complex urban or indoor environments.
Common applications and use cases
Fiber optic tethered drones are increasingly being used in tactical military operations where secure communications, covert operations, and avoiding detection are critical. It is well suited for tactical military offensive operations, reconnaissance, surveillance and intelligence gathering in environments where radio frequency detection and denial are expected.
Law enforcement and security teams also use these systems for continuous surveillance in sensitive areas, including monitoring activities, facility security, and hostage situations.
In all use cases, its ability to ensure a secure, interference-free, high-quality connection provides a clear operational advantage.
Trade-offs and drawbacks to consider
While fiber-tethered drones offer many significant advantages over wireless drones, several disadvantages and challenges are becoming a reality. The primary disadvantages of fiber optic drones include: flight distance limitations, excessive weight of the attached fiber package, fiber supply and manufacturing limitations, and the risk of losing the connection (and the drone) completely if the fiber is cut or damaged in flight.
The maximum flight distance of a fiber optic drone is limited to the total length of fiber in the attached enclosure. While some advanced manufacturers of these fiber rope cans have demonstrated the ability to efficiently achieve maximum distances of 20-40 km, many wireless drones are capable of flying much longer distances. This makes fiber optic drones less suitable for long-range missions that require wide coverage. Careful mission planning is essential to balance range, payload and fiber capacity.
Another challenge is the added weight of the attached fiber and enclosure hardware. Carrying excess weight increases the power requirements of the drone and reduces battery life, reducing maximum flight time. Additionally, greater weight negatively affects the drone’s overall speed. For military attack and supply UAVs carrying payload in addition to the fiber canister, reducing the weight of the fiber canister as much as possible is always a priority.
One of the biggest challenges that many entities face, and one that often goes unmentioned, is the lack of consistent access to high-quality bare fiber optics from a supply chain perspective. Optical fiber is the backbone of global communications and is experiencing rapid and continuous growth in demand. Sourcing bare fiber from major reputable manufacturers in the required quantities is very limited, or not even an option for most entities without a formal, pre-established supply relationship. Many drone users and their affiliated entities have also implemented material sourcing mandates, such as requiring all materials to be produced locally, reducing procurement options. Aside from fiber supply challenges, the successful design and production of tethered fiber drone box solutions requires highly specialized manufacturing equipment, processes and staff expertise that most entities lack.
Finally, since tethered fiber optic drones rely 100% on maintaining a physical fiber connection, if the fiber is completely severed or sustains significant damage in flight, the operator will lose connection and control, and the drone will be lost.
Learn more about fiber optic drone technology – contact M2 Optics
For more than two decades, M2 Optics has been the recognized leader in the design and manufacture of custom and buffered bare fiber optic solutions for essential communications applications. Based on this deep expertise, the company is 100% customized and manufactured in the USA. OptitherTM Drone enclosure interconnection solutions represent the latest game-changing innovations in the industry.
For more information or to partner with M2 to design a custom OptiTetherTM case based on your specific needs, contact us today.
