Lightweight optics is good for the military

Guest author Peter Kontros, European business development manager for fibre optics at Molex looks at the role of fibre optic connectors and cabling in military and aerospace system designs

Fibre optic technology has until recently been seen as a ‘black art’ – in terms of mechanical and environmental stability and cost of active components. However, as the commercial market has shown for many years, this is no longer true.

Cabling systems that use rugged cables and connect products and the transceiver technology is advancing apace, while costs are falling. Away from the PCB, a solid OEM acceptance has grown as the termination, test and cleaning of systems have become much more robust and repeatable processes.

When comparing copper telephone wire with fibre cabling it is clear that fibre is faster than copper, offers a wider bandwidth and its distance performance with respect to losses is greater. This is why fibre technology was used in the Typhoon Eurofighter, which was developed in the 1980s, and in today’s Joint Strike Fighter (JSF) Programme.

Ruggedisation, weight reduction, micro-miniaturisation and performance are all key elements for the military and aerospace industry’s selection process of interconnect solutions. Complex C4ISR applications, for example, require incredible speed, enormous bandwidth, signal integrity and analytic capabilities, without adding heat to the system.

Lightweight design is a priority in unmanned vehicles; here the smallest interconnect systems can help keep the system light and nimble. With these design criteria, fibre optics is becoming the transmission medium of choice and, due to the intrinsic benefits of security and immunity to RFI/EMI, the use of such links is not just desirable but is now essential.

Commercial off-the-shelf optical cable assemblies, such as Military 38999- and 28876-style circular connector cable assemblies and ARINC 400- and 600-style avionic optical assemblies, provide readily-available cost-effective and short lead-time solutions. Uniquely, design connectors, which can be terminated to both discrete fibre and optical ribbon cable, are ideal for use in avionics, flight-control equipment, mobile tactical field command platforms, EMI sensitive equipment, security, and other harsh-environment applications.

Flexible circuitry, backplane systems and standard connectors (FC, LC, MT, MTP, SC and ST) are all available for customised terminations to meet specific application requirements.

It is anticipated that the Boeing Dreamliner, A380 and A350XWB will use more fibre optic technology to support the requirement for more efficient airframes in terms of weight reduction, while supporting more services, such as control, communication and infotainment, on the various platforms.

Standards committees, such as the SAE, JEDEC and ARINC, are working with the leading connector manufacturers focusing heavily on fibre technology, particularly transceiver modules and infrastructure, in support of these high-speed intra-platform links.

With the advent of unshielded-twisted-pair cabling (UTP) the margins between copper and fibre are narrowing. Connector and cabling manufacturers have marched through at least five generations, each time to keep up with the increasing bandwidth requirements of LANs. We are now seeing 10 Gigabit Ethernet, as opposed to the 10Mbit/s Ethernet networks we had 15 years ago.

This technology is now ruggedised for the industrial environment and it is anticipated that it will also migrate into military and aerospace applications, complementing fibre optic technology.


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