By Thomas Mittermeier, ODU-USA

With multiple benefits for integrators and end users, a new generation of fiber-optic connections offers valuable development and the potential to eliminate critical vulnerabilities of military air platforms. This adoption of this technology is accelerated by the inclusion in new open VITA standards.

Due to a variety of factors, military aviation is an extremely challenging environment for the integration of electronic systems. Basic principles such as size, weight, and power (SWaP) optimization are beyond question and have always been one of the most central requirements for all components. Due to high environmental requirements, the components must be extremely robust and resistant, which is reflected in high development costs and prices. Spurred on by the drive for technological superiority, the market and the existing subsystems are developing at a rapid pace.

If integrators can choose from a large number of subsystem providers available on the market, this choice presents them with important decisions. Procurement contracts usually define strict requirements as to where and how the components must be available. No matter how promising a technology sounds and how much it would put the company ahead of the competition, a lack of availability can break the neck of the overall system.

Open standards = better time to market

This makes it all the more understandable that central military aviation programs prefer to rely on proven standards that are characterized by proven performance and multi-layered availability. It is therefore up to manufacturers to make their technological innovations available to the market as quickly as possible via open standards. This happened recently with the initiation of two new VITA standards that introduce a new contact technology to the world of embedded computing.

Fiber optic has been an integral part of data transmission technology for decades. Optimum SWaP features (extremely light, space-saving and incomparably fast) characterize the solution and make it the key technology for the complex board systems of military aircraft. However, precise transmission requires extremely time-consuming cleaning, which consequently results in high effort and increased costs. As no sensible alternative exists to date, MT ferrules are used en masse in the frame of standardized backplane and I/O circular connectors in modern platforms.

Expanded Beam Performance technology offers a remedy and embodies long-awaited features: little to no cleaning, a long service life and optimum optical transmission properties. Sounds good, but how is that possible?

Expanded Beam Performance is an advanced version of Expanded Beam contact technology. In contrast to the physical contact (PC) solutions commonly available on the market, it is characterized by contactless transmission of the light signals. As a result, signal transmission is less susceptible to contamination or interference due to mechanical shocks and vibrations. A long-service life is also possible, as there is no wear on the contact ends.

Expanded Beam technology has been known and used on the market for some time. However, previous connection systems could not keep up with the excellent transmission properties and high packing densities of PC solutions. These weaknesses have been eliminated by the innovative design of the Expanded Beam Performance ferrule. What remains is a highly potent contact technology that is characterized by the following features:

• 12 fibers per ferrule
• No cleaning required under normal conditions
• Extremely low insertion loss values even under harsh environmental conditions
• 50,000 mating cycles
• Insertion loss: SM: < 0.35 dB (typical) / < 0.7 dB (max.)/MM: < 0.15 dB (typical) / < 0.3 dB (max.)
• Return loss: SM: > 60 dB (typical) / ≥ 55 dB (min.)/MM: > 45 dB (typical) / ≥ 35 dB (min.)

The longevity of the technology makes it the perfect transmission variant for demanding applications such as military aviation. The greatly reduced maintenance requirements in combination with the long service life play a key role in the total cost of ownership. The systems also support the emergency services in critical situations, as platforms are ready for use again more quickly thanks to shorter maintenance times.

Important strategic steps were taken at the beginning of 2025 to ensure that the new system is quickly and widely available. VITA 95 and VITA 96 Working Groups were proposed and formed in January. VITA 95 is focused on circular I/O connectors based on 38999, Series III housing. VITA 96 defines different dimensions of backplane connectors for the transmission of up to 96 fibers.

Defining different dimensions

Thanks to the advanced technology, modules can be swapped within the system in a matter of seconds without the need for maintenance. Normally, this process requires extensive cleaning of the physical contact areas – every time they are swapped. Three variants: Type A, B and C offer three different dimensions of the connection solution, which is based on the apertures of the existing VITA 66 Optical Interconnect on VPX connection standard. This will make it easier for companies to integrate the new technology, as existing modules do not need to be modified. The individual fibers are connected as usual via optical transceivers, which can be attached directly to the circuit boards. The first versions of the new connection generation have already been presented by the German connection specialist ODU under the name ODU BACKPLANE.

In addition, the developing VITA 95 standard defines several variants of I/O interfaces that connect glass fibers via the Expanded Beam Performance ferrule. Here too, future solutions will be based on the dimensions of the well-known VITA 87 High Density (HD) MT Circular Connector standard. MIL-DTL 38999, Series III enclosures offer familiar handling to the users, simplifying the transition. ODU TACTICS currently offers four solutions in shell sizes #11, #13, #15 and #17.

Thomas Mittermeier is Strategic Business Development Manager for Aerospace/Military Fiber Optic Applications at ODU-USA. He specializes in advanced connectivity solutions.

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