Fiber optics interconnect has emerged as the only viable technology to carry the massive amount of information generated by high resolution radars, infra-red cameras and other sensors.
By: Gérald Persaud, VP Business Development and Michel Têtu, Senior Business Development Advisor
Command, control, compute, communicate, intelligence, surveillance, and reconnaissance systems (C4ISR) rely on accurate views of local situations for decisions that are critical to national defense. Fiber optics interconnect has emerged as the only viable technology to carry the massive amount of information generated by high resolution radars, infra-red cameras and other sensors. Fiber optic-interconnect are small, immune to EMI and has superior bandwidth to traditional copper interconnect.
Reflex Photonics technology brand optical embedded transceivers are small, rugged, lower power components enabling the transmission and processing of high bandwidth sensor information.
Illustration of the relation between the different elements of C4ISR systems (Command, Control, Compute, Communicate, Intelligence, Surveillance, Reconnaissance).
Intelligence, surveillance, and reconnaissance (ISR) trend is for more information and accurate views of the situations with longer mission times. For example, UAVs with high resolution sensors and high performance embedded computing have become an invaluable tool to defense. They can survey large areas quickly and at much lower cost than manned aircraft.
Parallel optics provides multiple high bandwidth interconnects in a space ten time smaller than co-axial copper interconnects. With almost unlimited bandwidth it is clear that all future interconnects for embedded systems will use parallel optics.
Reflex Photonics supplies chip size rugged parallel optics transceivers to operate in harsh military environments. These embedded parallel optical modules are qualified to MIL-STD-883E for severe environmental conditions.
High temperature materials and simple structure equals reliable performance in harsh environments.
System performance of an optical link is determined by the quality of the signal generated by the TX, lane impairments (fiber optics cable and interconnects) and the sensitivity of the receiver over a bandwidth range. Rugged transceivers must operate over wide temperatures (at least -40 ºC to 85 ºC) which makes it challenging to maintain low bit error rates (BER) at the high operating speed. For example, the laser response slows with temperature making it difficult to maintain an open eye at speed beyond 6 Gbps. At high temperatures the laser output power declines and causes a decrease in signal to noise ratio. As well, the response time decreases which can cause a high level of ringing. The TX eye diagram is a useful method to assess the quality of the signal generated over temperature. Open eyes correlates to low BER as the receiver is given more bit time to accurately discriminate a high signal from a low signal.
The eye diagram in figure below shows the LightABLE transmitting 10 Gbps at -40 ºC. It uses the 802.3ab Ethernet mask to show there is a huge bit time margin for the receiver to accurately detect a high from a low. This is why Reflex Photonics transceivers can deliver BER better than 10-15.
Reflex Photonics LightABLE™ embedded transceivers offer small SWaP-C, operation over industrial temperature range (-40 °C to 85 °C), a bit error rate (BER) as low as 10-15, survivability to storage temperature from - 57 °C to 125 °C. The LightABLE can be surface mounted using leaded or RoHS reflow processes or it can be plugged into a board with a Meg-Array socket. Mounting the LightABLE close to the electrical driver delivers the best signal integrity and lowest power operation. The optical fiber interface is a standard MT ferrule directly attached to the module for compatibility with standard connectors and cables.