Frequently asked questions

An FSO link converts data into a modulated optical signal, directs that signal through free space and detects it at a receiving terminal. Terrestrial systems commonly use infrared wavelengths which are also used in fibre-optic networks. FSO can deliver fibre-class data rates without installing a physical cable across the gap. Applications range from short links inside machinery and docking stations to connecting buildings, mobile platforms, ground-to-air or ground-to-space links and inter-satellite laser communication. Put simply: it is data on a laser beam.

An FSO system uses a transmitter, optical beam-forming elements, a free-space path, receiving optics, a detector and data interfaces, supported by mounting, alignment, control and power.

The data source drives a laser or other optical transmitter. Lenses or telescopes shape and direct the beam toward a receiving aperture, which focuses the light onto a photodetector or optical receiver. Electronics recover the data and pass it to the connected equipment. Practical systems also require a stable structure, coarse alignment, optional acquisition and tracking, diagnostics, management, environmental protection, power and safety controls. Bidirectional links may use separate beams or different wavelengths through a shared optical path.

Fibre is the preferred choice when a permanent cable can be installed economically and maximum availability is required. Conventional RF is flexible, supports non-line-of-sight or wider coverage in many cases and benefits from mature equipment, but capacity, interference, spectrum and security can be a limiting factor. Millimetre-wave radio offers high data rates but still uses regulated or shared RF bands and can be affected by rain and interference. FSO is useful when the link needs high bandwidth, low processing latency, RF independence, directionality, rapid deployment or freedom from a repeatedly moving cable and extra security from a direct link between transmitter and receiver.

FSO brings optical network capacity across a space where installing or repeatedly moving a cable is difficult. Its narrow beam limits energy outside the intended path, reduces interference with neighbouring links, and makes interception more difficult. Because the data path is optical, it is immune to RF congestion and jamming at the propagation layer. Many systems can be installed faster than trenching fibre and can provide a transparent physical link for standard interfaces. These benefits are strongest in high-bandwidth, controlled line-of-sight applications.

The optical beam must remain within the receiving aperture and field of view. Heavy fog or mist can scatter enough light to interrupt a terrestrial link. Wind, thermal expansion, vibration or motion can move the terminals out of alignment. Dirt, water, snow or ice can block or distort the optical path. Sunlight and turbulence can reduce receiver performance in some designs. These risks are managed through correct range and link-budget design, stable mounting, larger apertures or appropriate divergence, tracking, environmental protection, monitoring and redundancy.

Atmospheric particles absorb or scatter part of the beam. Dense fog droplets are close enough in scale to optical wavelengths to create high attenuation, especially over longer distances. Rain drops and many snowflakes are larger and often produce less attenuation per unit distance, though severe precipitation and accumulation remain important. Dust, smoke and pollution can reduce visibility or coat optics. Turbulence can cause intensity fluctuations and beam wander, while sunlight can raise detector background noise. Wavelength, path length, aperture, field of view and receiver filtering all affect sensitivity.

The calculation begins with transmitted optical power. It subtracts losses from transmit optics, beam spreading, path geometry, atmospheric attenuation, pointing error, receive optics and coupling. The result must remain above the receiver sensitivity and below its overload limit. A reserved margin for weather, vibration, installation tolerance, contamination, ageing and uncertainty is added. A useful link budget identifies normal, worst-case and failure thresholds and connects them to the desired service availability.

Short industrial and docking links can support tens or hundreds of gigabits per second across centimetres or metres. Distance between buildings may cover hundreds of metres or kilometres at gigabit-class rates. Ground-to-space and inter-satellite systems use specialised telescopes, acquisition/tracking and optical terminals over far greater distances. There is no single FSO maximum: higher data rate normally demands more receiver performance and may reduce available link margin unless optics, power, coding or aperture are changed.

Light travels through air at nearly the same speed as in vacuum, so propagation across a terrestrial FSO path contributes almost zero delay. Most added latency comes from electro-optical conversion, DSP, coding/FEC, timers, media conversion and network equipment. A simple optical bridge can carry standard Ethernet or other compatible signals without routing or packet inspection. Transparent optical systems may carry externally generated waveforms, provided wavelength, power, modulation, fibre and receiver requirements are compatible.

FSO beams are narrow, so the transmitter must remain pointed at the receiver. Tracking compensates for installation error, thermal movement, vibration or platform motion.

FSO can be highly reliable in a well-designed operating envelope, but availability is site- and weather-dependent. Critical links usually combine FSO with a redundant optical, RF or fibre path.

An attacker normally needs physical access near the line of sight and must couple light without causing a detectable loss. The beam does not travel through walls and is unaffected by RF jamming. FSO is a valuable physical-security layer, not a replacement for cryptography or cybersecurity.

Laser safety depends on wavelength, power, beam diameter/divergence, aperture, exposure time, accessibility and fault conditions. IEC 60825-1 provides the principal product classification framework, including Class 1 and 1M categories. Optical wireless operation does not require a radio-frequency allocation, but electrical, EMC, workplace, building, environmental, machinery and sector regulations can apply.

Installation needs a site survey, a clear line of sight, stable mounts, power, data connections, alignment and an acceptance test. Maintenance is mostly optics, mounts, monitoring and software. A KORUZA MINI link inside a machine needs practically none.

Strong FSO applications include machine motion and robotics, docking/data offload, temporary high-capacity links, RF-sensitive facilities, secure point-to-point paths, difficult physical crossings, research platforms and specialised communication. A customer should prefer fibre when permanent cabling is practical and maximum availability is needed. RF is often preferable when adequate capacity is available, line of sight cannot be guaranteed or broad mobility/coverage matters more than directionality. The best design may combine technologies for diversity.

KORUZA MOD is designed for customers who need specific FSO capability. Its mechanically aligned baseplate can carry different plug-in modules, allowing the optical path, data rate, range, tracking, control and packaging to be selected around the required user application. KORUZA Pro generally addresses fixed or medium-range links up to about 150 m, with special configuration up to 1 km, while KORUZA Mini addresses compact links for up to 10 m for docking, robotics and machine motion. A KORUZA MOD configuration may be delivered as a development platform, a configured kit or can be used as a basis for a custom designed product.

KORUZA MOD separates the system into optical and supporting modules. Optical options include 1 Gb/s and 10 Gb/s BiDi links with 50 mm optics, compact 10 Gb/s Mini modules, a split transmit/receive Mini option, a 25 Gb/s BiDi module, a short-range 100 Gb/s QSFP28 module, 20 mm and 50 mm transparent optical interfaces, a MEMS attenuator and an EDFA. Supporting items include 1/10/25 Gb/s interface boards, a tracking camera, pan/tilt mechanisms, a main controller, an outdoor enclosure and training. The final combination is selected from the application requirements.

We have delivered KORUZA links at 1 and 10 Gb/s. The 25 and 100 Gb/s configurations are in the catalogue and at an earlier stage. The optical channel itself is not the bottleneck: the data rate is set by the transceiver, the interface board and the link margin. The 100 Gb/s module is a compact QSFP28 head for links of roughly 1 to 10 m. A higher rate does not come with the same range or weather tolerance for free, so for each project we choose the transceiver, optics, interface and tracking together and confirm the line rate, useful payload, duplex mode, error rate and distance before we quote.

Range depends on data rate, transmitter power, receiver sensitivity, aperture, beam divergence, alignment, weather and required availability. Speeds can go up to 10 Gb/s and 100 Gb/s for 1-10 m; 10 Gb/s 50 mm variants for 50-150 m; 25 Gb/s variant for 50-150 m; and a 1 Gb/s variant for 100-200 m. Longer-range systems are possible as custom engineering or research, but they need different optics, amplification, tracking, safety analysis and availability modelling.

For a representative 150 m configuration, KORUZA has free-space attenuation below about 3 dB and an available margin in the approximate 15-21 dB range, depending on the optical transceiver. The current KORUZA MOD catalogue contains several different power/sensitivity pairs, so there is no single KORUZA link budget. We prepare a project-specific model using transmitter limits, receiver sensitivity and overload, optical coupling, aperture, divergence, path loss, atmospheric attenuation, alignment errors and the customer’s required availability.

KORUZA is designed with link margin and alignment control for real deployments, but availability depends on local visibility and distance. Internal testing has included fog influence, and previous design calculations used severe attenuation cases around 100 dB/km. At 150 m that corresponds to approximately 15 dB of atmospheric loss, which selected configurations may accommodate if sufficient margin remains. Dense fog is not always survivable, particularly over long range. Rain, snow and temperature usually matter less through direct atmospheric attenuation, but wind, thermal expansion, ice, dirt and physical blockage can cause misalignment or obstruction.

KORUZA can combine camera-assisted alignment, central control and motorised pan/tilt tracking. The mechanism is selected based on deployment scenarios (fixed structures, thermal movement, machinery, docking or mobile platforms). The complete answer depends on the required angular range, resolution, vibration, speed and re-acquisition time. High-speed MEMS correction is under development.

Short-range FSO can remove a physical data cable across a controlled motion gap. KORUZA is already used in use cases like 1 Gb/s and 10 Gb/s linear-motion machine integration, tracked robotics and 25/100 Gb/s docking. Typical opportunities include high-speed inspection, CNC and pick-and-place equipment, autonomous robots, UAV or vehicle docking, and rapid sensor-data offload. The integration must account for motion geometry, line-of-sight interruptions, acquisition time, acceleration and the required network behaviour during brief outages.

Depending on the configuration, KORUZA uses SFP, SFP+, SFP28, QSFP28 or other optical modules and can bridge a high-speed data path without integrated routing or packet processing. MOD interface boards add optical monitoring and expose parameters through USB or serial connections. Exact host compatibility, latency, jitter, FEC and protocol transparency must be confirmed for the selected transceiver and interface.

FSO provides useful physical security characteristics: the beam is directional, does not spread through walls like conventional radio and does not occupy an RF channel. An interceptor generally needs physical access close to the optical path and must avoid disturbing the received signal. This reduces the interception and RF-jamming surface, but it does not replace encryption, authentication, endpoint security, secure management or physical protection of the terminals.

KORUZA uses near-infrared optical technology and is designed for safe operation. It normally does not require an RF-spectrum licence, but every final product and installation must still meet applicable laser, electrical, EMC, workplace and sector regulations.

The first step is a site and application (use-case) survey: distance, line of sight, mounting stability, visibility/weather, motion, network interface, power and target availability. Fixed systems need secure mounts and clearance from growing vegetation or other obstructions. A typical KORUZA MOD robotics configuration uses 24 V DC / 2 A power, SFP+ for data, 100 Mb/s Ethernet for management and a small out-of-band management channel between the units. Outdoor projects also require appropriate enclosure, cable entry, grounding, environmental protection and safety review.

There is no list price, because there is no single product. A KORUZA MINI pair starts at a few hundred euros; a KORUZA PRO pair is a few thousand. What moves the total is everything around the optics: tracking, weather protection, transparent or coherent operation, certification, integration engineering, installation and support. Every project starts with a feasibility study against your requirements, continues as a paid integration project, and only then do we quote pilot or production quantities. We work this way because off-the-shelf FSO bought from a datasheet is how people end up disappointed, and we would rather tell you what will not work before you have paid for it.

KORUZA has been through several generations since 2012: 1 Gb/s and 10 Gb/s products, field experiments, a great deal of alignment work and industrial installations. The MOD platform is what R&D teams, OEMs and custom projects use today. Module maturity varies, so before we send a proposal we tell you, item by item, whether it is available, a prototype, in development or custom-only.

The process has three stages. First, we define the use case with you and prove it is feasible. Second, we develop and validate the integration: optics, mechanics, interfaces, tracking, safety and environmental requirements. Third, we prepare the design for pilot or production. To do that we need: payload throughput, distance, line of sight, motion, acquisition time, weather, acceptable outages, redundancy, host interface, physical size, power, compliance, annual volume and target cost.