A short introduction to the applications of the OWC in to the short-range to the deep-space applications. Form visible light communications to wearables, OWC is a way to reuse our natural space of communications the free space and the light. Seminar presented at Universitat Politecnica de Valencia, Spain during the OQCG regular seminars' series, March 2014. by Dr Joaquin Perez

1. OPTICAL WIRELESS COMMUNICATIONS
“From the space to the chip”
OQCG Short Seminar Series
March 2014

2. My Snapshot
PhD (2009) @ UPV - “Wireless comms integration on Optical networks (RoF,
UWB, WiMAX, WDM, PolMux, …)”
• Previous Research topics about OWC
– Atmospheric turbulence effects on outdoor OWC
– Hybrid systems FSO/RF
– OWC for intelligent transport system
– Others : LTE over fiber, Indoor VLC systems (TV/Internet streaming)
Indoor POF+VLC
• Common topics:
– Optical transceivers
– New efficient modulation schemes
– Optical transmission
March 2014 - OQCG Seminars

3. Optical Wireless Communications
• Ancient as the human kind
– beacon fires, smoke, ship flags or semaphore telegraph
– Photophone 1880 A.G.Bell
• Laser revolution  1962 MIT Lincoln Labs OWC GaAs light source over 30
miles for TV transmission
– Beam divergence problems, atmospheric effects, the fibre appears at 70’s to
solve those problems
– OWC relegated to satellite interlinks, IrDA, some military applications.
March 2014 - OQCG Seminars

4. Optical Wireless Communications
• Advantages: Low Cost, license free, high BW access solution
– Light sources : LASER – LED – OLED
• Problems: atmospheric losses, turbulence, and pointing errors
• Many applications
– Optical angular moments for Quantum Cryptography
– Satellite optical networks
– Wearable interaction
– Indoor low-cost communications
– Enterprise/campus connectivity
– Video surveillance and monitoring
– Backhaul for cellular systems
– Broadcasting
– Redundant link and disaster recovery
March 2014 - OQCG Seminars

5. Ultra-long and long range OWC
• Sports events (F1)
• Campus, MAN networks
(Cablefree, LightPointe ...)
• Security and defence
communications
(CASSIDIAN, EADS, ...)
March 2014 - OQCG Seminars

6. Air-to-Ground FSO
• Air-to-ground FSO quantum-
key distribution
communication
(Nature Photonics 7, 382–386 (2013))
(Photos: DLR)
Speed of 290 km/h at a distance of 20 km
or 4 mrad/s
March 2014 - OQCG Seminars

7. Space-ground FSO
• Laser Communications Relay
Demonstration LCRD
• High bandwidth geo-sync to
ground optical link
– Downlink: 1.2 Gbps
– Uplink: 1.2 Gbps
– LCRD Payload Flight in 2017 on
Loral Commercial Satellite
• Bidirectional low Earth orbit-
to-ground optical link
– 2 Mb/s UL and 50 Mb/s DL
M.W. Wright et al. , 26 September 2011, SPIE
Newsroom.
(Photos: NASA and SPIE)
March 2014 - OQCG Seminars

8. FSO networks
• Intra-satellite
• Campus networks
• FSO link needs line of
sight (LOS)
• Link Obstacles??
– Buildings, fog,
turbulence...
– No connection!
• A mesh topology as a
solution??
(Photos: ESA)
March 2014 - OQCG Seminars

9. OWC comms and adverse channel effects
Mitigating Turbulence Effect
• Spatial Diversity Solutions
• Relay-Assisted FSO Networks
• Hybrid RF/FSO Links
OWC impairments are
derived from the channel
variations
• Adverse Channel Effects
– Background Radiations
– Pointing Errors
– Atmospheric Loss
– Atmospheric Turbulence
March 2014 - OQCG Seminars

10. Medium range OWC
• IR indoor comms
– Irda extended (Giga-IR)
• Vehicle-2-Vehicle comms
– Volvo Intelligent road concept
• Visible Light Comms - VLC
– Li-Fi, internet
– LED shopping assistant
March 2014 - OQCG Seminars

11. LED and VLC
• RGB • Blue Chip + Phosphor
- Well-known technology
- Limited use due to difficulties in
RGB balancing
- Phasing out in lighting industry
- Wide modulation bandwidth
- Popular for today general lighting
industry
- Standardised for illumination and
communications
- Limited modulation bandwidth
White Light emission
March 2014 - OQCG Seminars

12. LED and VLC
• LED -> PN junction -> Small transit time
• Modulation BW from 3 MHz to 20 MHz
• Enough for communications?
– Equalisation techniques
• Up to 40 Mb/S @ 400 Lux, 2m range [1] using multi-
tone equalisation at transmitter
– Complex modulation
• PAM
• OFDM  OMEGA FP7 project (2011) (Siemens/HHI)
has demonstrated 84 Mbps OFDM/QAM – over 3m
[2]
– MIMO as a diversity technique
• 4x4 50 Mb/s [3]
– Gigabit VLC = EQ + OFDM + MIMO [4]
[1] H. Le-Minh et al., "High-Speed Visible Light Communications Using Multiple-Resonant Equalization", IEEE PTL 15 (20), Jul. 2008
[2] http://www.youtube.com/watch?v=AqdARFZd_78
[3] A. Burton et al. “Experimental Demonstration of 50 Mb/s Visible Light Communications using 4×4 MIMO,” IEEE PTL, March 2014
[4] G. Cossu et al. “2.1 Gbit/s Visible Optical Wireless Transmission”, ECOC 2012 , P4.16
March 2014 - OQCG Seminars

13. LED and VLC
• Mobility
– NLOS must work
– Channel reflections
– Smart receiver
• Diffuse receiver: direct and
reflected path
• Multiple receivers: best signal
• LOS vs NLOS: GAIN 20 dB
• Light dimming
Key effects
– The SNR is no longer the advantage
– Signal could be discontinued
Main dimming technologies
– Driving current reduction  lower
PTx and SNR
– Pulse width modulation (PWM) 
Signal disruption
TransmitterReceiver
AWGRTO
Spectrum
analyzer
0% 50% 75% 100%PWM MSR
30 Mb/s
50 Mb/s
70 Mb/s
By A. Burton et al. To be published in 2014
March 2014 - OQCG Seminars

14. LED VLC integration
• Video streaming over LED link
• 10 Mb/s
• Nov. 2013
March 2014 - OQCG Seminars

15. LED - OLED
• Solid-state light emitting diode (LED)
– Compact, cheap, powerful
– 50% light
– More than 50,000 hours lifespan
• Organic light emitting diode (OLED)
– Flexible and bendable panel
– Extensively used in high-end display products,
– HDTV and Smartphone
March 2014 - OQCG Seminars

16. OLED Devices
March 2014 - OQCG Seminars

17. OLED Current State-of-Art
• Efficiency
– 100% internal quantum efficiency (Fraunhofer IPMS – COMEDD, 2012)
– Brightness 2.000 cd/m², 5mm thickness (Verbatim Velve, 2012)
– 120 lumen (~table lamp) (Philip Lumiblade GL350, 2012)
– 80 lumen/watt with 20.000 hours of lifetime (LG, 2012)
March 2014 - OQCG Seminars

18. OLED Current State-of-Art
• Applications
– Dominant in high end Smartphone display products: Super-AMOLED,
(Samsung Galaxy S3 phone, 2012)
– 55 inch OLED HDTV (Samsung Electronics, 2012)
– 6 inch E-paper on plastic (XGA, 14 gram, 0.7mm thickness), (LG, 2012)
– Solar OLED car (BASF, 2012)
– Flexible AMOLED display (Samsung patent, 2012)
– None of the commercial applications is for communications!
March 2014 - OQCG Seminars

19. Electrical Characterisation
• For lighting
– Large panel  better for illumination
 larger capacitor value
• For communications
Larger capacitor value  slow response
Rp - electrode contact resistance
Rd - diode resistance
C - diode capacitance
March 2014 - OQCG Seminars

20. OLED – Techniques
Aim: High-speed OLED VLC system (Mbit/s over kHz bandwidth)
• Analogue Equalisation
• Decision Feedback Equalisation
• OFDM / QAM
• ANN
– P. A. Haigh, Z. Ghassemlooy, and I. Papakonstantinou, "1.4 Mb/s White Organic LED Transmission System using
Discrete Multi-tone Modulation," IEEE Photonics Technology Letters, vol. PP, pp. 1-1, 2013
– Paul Anthony Haigh, Francesco Bausi, Zabih Ghassemlooy, Ioannis Papakonstantinou, Hoa Le Minh, Charlotte Fléchon,
Franco Cacialli, "Visible light communications: real time 10 Mb/s link with a low bandwidth polymer light-emitting
diode," Opt. Express 22, 2830-2838 (2014);
.
March 2014 - OQCG Seminars

21. Short and ultra-short range OWC
• Wireless body area networks
– Wearables :
– Toys, dresses and LED interactions
• Disney research [1]
• Low data rate
• Device integration
• OWC Underwater comms
– Offshore platforms sensor networks [2]
• Water scattering , attenuation by refraction,
[1] Stefan Schmid, Giorgio Corbellini, Stefan Mangold, and Thomas R. Gross. 2013. LED-to-LED visible light communication networks. In Proceedings of the
fourteenth ACM international symposium on Mobile ad hoc networking and computing (MobiHoc ’13). ACM, New York, NY, USA, 1-10.
[2] J. A. Simspson et al. “Smart Transmitters and Receivers for Underwater Free-Space Optical Communication”, IEEE JSAC, 5 (30), June 2012
Photos: Disney ©
March 2014 - OQCG Seminars

22. Ultra-short range OWC
• Chip to Chip comms
– Couplers fibre to chip
• Grating couplers, tappering, …
• Future sensor networks (O’Brien, Oxford)
March 2014 - OQCG Seminars

23. Future of OWC
• Ultra short range  depends on photonic chip
• Short-range  depends on consumer adoption (Li-Fi, wearables, …)
• Medium range  niche market, established, future depends on the
channel impairments solutions and the deployment of OWC networks
under extrem situations
• Long-range / ultra long  Satellite is OWC the solution?
– VALIDATION OF TURBULENCE MITIGATION TECHNIQUES FOR
HIGH DATA RATE OPTICAL LINK - ESA Invitation To Tender 7386
– NASA last issues
– DLR and quantum tranmission
• New OWC SME will engage the big players?
March 2014 - OQCG Seminars

24. Latest news on OWC
“Smartphone concept incorporates LiFi sensor for receiving light-based data” ,
OLEDCOMM at CES 2014
“Pure LiFi transmits data using light (video)” at MWC 2014
“Charge and receive data with light: TCL Communication/ALCATEL ONETOUCH
and Sunpartner Technologies announces the first fully integrated solar
smartphone” at MWC 2014
“High-Speed Stock Traders Turn to Laser Beams” at WSJ FEB 2014
“Extreme Test for the ViaLight Laser Communication Terminal MLT-20 – Optical
Downlink from a Jet Aircraft at 800km/h”, EADS & DLR Dec 2013
“NASA Historic Demonstration Proves Laser Communication Possible ” by NASA
Nov 2013, Lunar Laser Communication Demonstration or LLCD
March 2014 - OQCG Seminars

25. MWP & OWC?
QKD & OWC?
POF + ACCESS + OWC + …?
And now?
March 2014 - OQCG Seminars

26. Optical and Quantum Communication Group (OQCG)
iTEAM Research Institute
Universitat Politecnica de Valencia, Spain
http://joaquinperezsoler.blogs.upv.es/
joapeso@upv.es // Gscholar // @joakin_perez
March 2014 - OQCG Seminars
DR JOAQUIN PEREZ
POSTDOCTORAL RESEARCH FELLOW