CEIS School Seminar 22/02/12

Improving the Data Rates of Organic Light Emitting Diodes

Andrew Burton, Yr 2

Supervisors

Dr. Hoa Le Minh

Prof. Z. Ghassemlooy

CEIS School Seminar

Light Emitting Diodes (LED)

CEIS School Seminar

Organic Light Emitting Diodes(OLED)

CEIS School Seminar

Large Panel OLEDs used for Home and Office Lighting

CEIS School Seminar

Visible Light Communications

CEIS School Seminar

What are Organic LEDs?

Substrate (Glass, plastic)

Anode (+’ve)

Conductive Layer (Organic Molecules or Polymers)

Emissive Layer (Organic Molecules or Polymers)

Cathode (-’ve)

CEIS School Seminar

OLED Electrical Model

R d

R p

C

Rp = Contact resistance of electrodesRd = Diode resistanceC = Diode capacitance

CEIS School Seminar

OLED testing and Characterisation

Test 2: Device Linearity

0 2 4 6 8 100

2

4

6

8

10

12

14Vrec with Vtx for the OSRAM OLED

Vtx (V pk-pk)

Vrx

(m

V p

k-p

k)

IDC=100mAIDC=150mAIDC=200mAIDC=250mAIDC=300mA

Test 1: Illumination Test 3: Bandwidth

101

102

103

-10

-8

-6

-4

-2

0System Bandwidth

Frequency (kHz)

No

rm

alis

ed

am

pli

tud

e (

dB

)

Test 4: Bit Error Rate

100 200 300 400 50010

-2

10-1

100 BER of OSRAM OLED

Rb (kbps)

BE

R

0 100 200 300 400 5000

100

200

300

400

500

600

700

800

Bias Current (mA)

Illu

min

an

ce (

Lu

x)

Illuminance at 10 cm for OSRAM OLED

CEIS School Seminar

Post Analogue RC Equalization

101

102

103

-10

-8

-6

-4

-2

0System Bandwidth

Frequency (kHz)

No

rm

ali

se

d a

mp

litu

de

(d

B)

CEIS School Seminar

RC Equalisation Results

100 200 300 400 50010

-2

10-1

100 BER of OSRAM OLED

Rb (kbps)

BE

R

Eq1Eq2Raw

CEIS School Seminar

?

100 200 300 400 50010

-2

10-1

100 BER of OSRAM OLED

Rb (kbps)

BE

R

Eq1Eq2Raw

CEIS School Seminar

Decision Feedback Equalisation (DFE)

CEIS School Seminar

DFE Results

CEIS School Seminar

Orthogonal Frequency Division Multiplexing (OFDM)

CEIS School Seminar

Experimental Setup

CEIS School Seminar

OFDM Results

CEIS School Seminar

Conclusions

RC analogue equalisation is not suitable for systems running at low data rates

With DFE equalization we can achieve error free communications up to 500 kbps

With OFDM we can achieve error free communications in excess of 3 Mbps

The financial support received from the schoolof Computing, Engineering and Information Sciences at the University of Northumbria

CEIS School Seminar

Acknowledgements

Fellow author and researcher Paul Anthony Haigh

MATLAB Guru Dr. Sujan Rajbhandari

CEIS School Seminar

PublicationsJournal1. H. Le Minh, Z. Ghassemlooy, A. Burton, P.A. Haigh, S.K. Liaw, “Experimental Study of

the equalisation for Organic Light Emitting Diodes in Visible Light Communications”, 2011.

Conferences 2. A. Burton, C. Amiot, H. Le Minh and Z. Ghassemlooy, “Design of an integrated optical

receiver for mobile visible light communications” 12th Annual Symposium on the Convergence of Telecommunications, Networking and Broadcasting, Liverpool, 2011, pp.286-289

3. H. Le Minh, Z. Ghassemlooy, A. Burton, and P. A. Haigh, "Equalization for organic Light Emitting Diodes in Visible Light Communications," IEEE Global Communications Conference 2011 (IEEE GLOBECOM 2011), Workshop on Optical Wireless Communications in Houston, USA, 5-9 December, 2011.

Posters 4. A. Burton, “Smart White LED based Lighting and Communications”, Northumbria

Research forum, Newcastle upon Tyne, 2011 5. A. Burton, “Visible Light Communications using Organic Light Emitting Diodes”, EPRSC

Photonics Communications Workshop, Oxford, 2011

CEIS School Seminar

Publications (under review & writing)

Conferences 6. A. Burton, H. Le Minh , Z. Ghassemlooy, S. Rajbhandari ,P. A. Haig “Smart Receiver for

Visible Light Communications: Design and Analysis” CSNDSP 2012, Poland7. A. Burton, H. Le Minh, Z. Ghassemlooy “Smart Visible Light Communications Receiver ”

IEEC 2012, Vietnam

Journal8. A. Burton, P.A. Haigh, H. Le Minh, Z. Ghassemlooy , S. Rajbhandari and S.K. Liaw,

“Increasing Data Rates in Organic Light Emitting Diodes for Visible Light Communications” , IEEE Journal of Light wave Technology

9. A. Burton, H. Le Minh, Z. Ghassemlooy , S. Rajbhandari and S.K. Liaw, “The Full Design and analysis of a Smart Receiver for Visible Light Communications”, IET- Communications

CEIS School Seminar

Awards

1. Full Studentship from the School of Computing, Engineering and information Sciences Northumbria University to carry out my Ph.D.

2. Awarded best performing first year PhD student for the School of Computing, Engineering and information Sciences, May 2011

3. IEEE UK & RI Communications Chapter Tutorial grant for “Protection Switching in Communication Networks”, 16th European Conference on Networks and Optical Communications, 2011

4. IEEE Travel grant for Wavelet transform workshop, Northumbria University, 2011

CEIS School Seminar

Questions???