The objective of this white paper is to show how important and critical optical interconnect is becoming in the development of high-performance embedded systems.
By: Gérald Persaud, VP Business Development and Michel Têtu, Senior Business Development Advisor
Embedded Systems Market to Reach $133B by 2020*
Eyes and ears everywhere
For military and aerospace applications, C4ISR (Command, Control, Compute, Communicate, Intelligence, Surveillance, Reconnaissance) is invaluable for almost instantaneous high-end decision making.
Intelligence, Surveillance, and Reconnaissance Process
The Intelligence, Surveillance and Reconnaissance process (ISR) requires the collection and processing of signals generated by a large amount of sensors of various types like active electronically scanned array (AESA) radars, high resolution cameras, sonars and so on. Analog signals are digitized and transmitted to a high performance embedded computing unit (HPEC) for data fusion and processing through high bit-rate fiber-optic links. Through deep learning algorithms, actions to be taken are identified and communicated to decisional centers.
ISR Technology Trends
HPEC are made of multiple high-speed microprocessors, memory and storage set on electronic boards usually interconnected through copper backplane circuitry.
However with the data rate of these interconnects reaching over 10 Gbps, optical interconnects begin to be the preferred choice due to their high bandwidth, high density I/O, low loss, low weight, and immunity against EMI.
- Sensors: higher resolution cameras and radars
- Processor: multicore, low power GPGPU, GPP, FPGA
- Storage: solid state, small, rugged, reliable (RAID)
- Sensor fusion: correlate information from sensors
- Computing: Virtualization, parallel processing
- Small SWaP: more capability for SFF (3U VPX)
- All digital: multi-purposed, software defined functionality
- Intelligent: learning machines
- Data rich: real-time and historical data
- Secure: hack-resistant communications
- Reliable: no single point failure
- Small: more payload for other systems
- Scalable: simple upgrades, long life
- Multi-purposed: target ID, weather, communications.
Illustration of the relation between the different elements of C4ISR systems (Command, Control, Compute, Communicate, Intelligence, Surveillance, Reconnaissance).
Applications of optical interconnect in some high-performance systems
US Air Force Space Surveillance Network
Active electronically scanned array (AESA) radar
- Detect, track, catalog satellites and debris on earth orbits
- S-Band (2 GHz to 4 GHz)
- 36 000 independent radiating elements
- Can generate thousands of radar beams
- Separate from transmitter array
- 86 000 independent receiving elements
- DBF and frequency multiplexing allow for thousands of received beams
- Four high-resolution visible light cameras
- Uses 368 CCD COTS 5 Mp cameras
- 4×48 fiber optical ribbon cables
- 16×SNAP 12 @ 3 Gbps offering 600 Gbps total I/O throughput
Optical interconnect is used on ARGUS IS system
- High BW, low latency
- Small SWaP
- High density
- Defines system performance
Electrical vs optical interconnect power consumption
This diagram shows a rough evaluation of electrical power consumption for the connection of a sensor to an embedded computer system. Here we only consider the front-end of each system. Optic interconnect need 2 to 3 times less power than an electrical connection.
Summary of Embedded Optics Benefits
- Proven: Thousands used in aerospace and defense applications
- Scalable BW: 28 Gbps+
- Receiver sensitivity: –12 dBm
- Low bit error rates: 10−15
- Low loss: 0.003 dB/m (OM3 @850 nm)
- Reach: 300 m (OM3 @10G)
480G full duplex I/O. FPGA processors, server cards, and cellular systems.
- Chip size optical transceivers
- Less than 5 mm high
- Light weight electronics and glass fiber
- I/O density: 48 fibers in MT connector
- Low power consumption: 1.2 W for 12 lanes @10 Gbps
Micro-coaxial connectors compared to optical MT ferrule connector
- Complies with Telcordia GR-468-CORE and MIL-STD-883E standards for severe environmental conditions.
- Operating temperature: −40 °C to 85 °C operation @ 10 Gbps
- Storage temperature: − 57 °C to 125 °C
- Moisture and thermal shock resistant
- EMI and EMP immune
VPX optical interconnect standards
- ANSI/VITA 66.0: Optical Interconnect On VPX
- ANSI/VITA 66.1: Full Size MT Variant
- ANSI/VITA 66.2: ARINC 801 Variant
- ANSI/VITA 66.3: Mini-Expended Beam Variant
- ANSI/VITA 66.4: Half Size MT Variant
VITA 66.X standard
Image courtesy of TE Connectivity
VITA 66.4 standard
Image courtesy of ELMA
VITA 65: Open VPX
VITA 67.3C: VPX: Coaxial & Optical Interconnect,
VITA 76: High Performance Cable Standard
VITA 78: Space VPX Systems
VITA 78.1: Space VPX Lite
VITA 74 VNX: Small Form Factor VPX
VITA 67.3C standard
Image courtesy of TE Connectivity
LightCONEX blind mate optical interconnect
For a higher level of integration, Reflex Photonics in collaboration with Amphenol Aerospace, developed the LightCONEX™ optical blind mate connectors where the optical transceiver is directly embedded in the plug-in module connector following ANSI/VITA VPX technology.
- Supports 2 level maintenance
- Integrates optical transceiver into plug-in module connector
- Less board space needed for optical interface
- Fits VITA 66.4 backplane aperture for upgrades
- No need for fiber optic handling
VPX board with VITA 46 and LightCONEX plug-in connectors.
ELMA 3U VPX backplane with VITA 46 and LightCONEX connectors.
Close-up of the LightCONEX plug-in module connector.
Close-up of the LightCONEX backplane connector.
VPX optical solutions with Reflex Photonics embedded optics
Amphenol VPX media converter
- 6U VPX media converter
- Converts backplane high-speed signal to front optical and electrical Ethernet I/O
- 32 × 10G BASE SR in a VITA 66.1 connector
- 4 × 10G BASE-T and 8 × 1G BASE-T
Interface Concept Optical FMC Board
- Transceiver board (12TX + 12RX)
- 120 Gbps full duplex
- Supports front panel Optical Interface
- Interfaces with 3U VPX FPGA boards
Meritec Active Optical Module
- Extends electrical reach to 100 m @10Gbps
- Converts electrical to optical signals
- Size 17 VITA 76 electrical connector
- 12-lane MT optical in a size 11 shell
Reflex Photonics rugged parallel optic transceivers meet the requirements for harsh environment applications and offer:
High performance with less SWaP-C
Operation under industrial temperature range (-40°C to 85°C) with BER as low as 10−15 delivering 10 Gbps/ch and –12 dBm sensitivity. Less than 5 mm high. Low power consumption 100 mW/ch.
Thousands used in aerospace and defense applications.
Fully qualified following Telcordia GR-468-CORE and MIL-STD-883E standards for severe environmental conditions.
Successful 2500 h Accelerated Life Testing @ 100 °C.
Storage temperature from −57 °C to 125 °C.