T1 Tutorial description

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1 This tutorial, entitled : T Tutorial description Visible light communications in smart road infrastructures, reports four work areas: Admission Regulation of Traffic to Improve Public Transport in Urban Areas Essays for optical communications Indoor positioning using a-sich technology Connected cars: road to vehicle communication through visible light

2 II Work Area: Essays for optical communications Schematic diagram of the transducers essays. An indoor, line-of-sight visible light communication link.

Motivation and Objectives Optoelectronic WDM system: MAIN WORK AREAS:

Experimental Design Applications Which kind of amorphous Si/SiC

wavelengths for the transmission over WDM networks, in the visible

3 Motivation and Objectives Optoelectronic WDM system: MAIN WORK AREAS: RESEARCH QUESTION : System Architecture Optoelectronic Algorithm Interface Experimental Design Applications Which kind of amorphous Si/SiC transducers, should be developed to allow the recovery of specific wavelengths for the transmission over WDM networks, in the visible spectrum, that could compete with conventional detection electronic devices in optical communications industry?

4 Outline State of art: Experimental Design Work Area. The original idea. ias controlled device: Voltage and Optical bias. Self amplification. Photonic filters. Photocurrent (a),4 NC,3, 75 Hz,, p-i(a-sic:h)-n/ito/p-i(a-si:h)-n - V -5 V V 3 V Dynamical effects: A two stage active circuit. Optoelectronic simulator. Wavelength (nm) Reconfigurable active filters: Opto-electronic conversion. Optoelectronic logic functions. Conclusions and future trends.

State of art of a-si/sic Photodiodes Produced by PECVD The thickness of the front photodiode was optimized for blue collection and red transmittance

- ),6 #M79 (mwcm - ) -x -8,4 #M69(, L =) -4x -8, #M63( whithout,8 L =) optical bias -6x -8,6 S =65 nm #M79( L =),4 NC#5 (pin/pin) L =55 nm L =65 nm,

the applied bias Light-to-dark Sensitivity depends strongly on the carbon concentration P. Louro, M. Fernandes, A. Fantoni, G. Lavareda, C.

5 State of art of a-si/sic Photodiodes Produced by PECVD The thickness of the front photodiode was optimized for blue collection and red transmittance The thickness of the back photodiode was adjusted to achieve high collection in the red spectral range a) Photocurrent (A), #M69(mWcm - ),8 #M63(mWcm - ),6 #M79 (mwcm - ) -x -8,4 #M69(, L =) -4x -8, #M63( whithout,8 L =) optical bias -6x -8,6 S =65 nm #M79( L =),4 NC#5 (pin/pin) L =55 nm L =65 nm, -8x -8 L =45 nm, Sensitivity (A/W) Wavelength Voltage (V)(nm) p-i-n p-i-n Green lue Color rejections function on the applied bias Light-to-dark Sensitivity depends strongly on the carbon concentration P. Louro, M. Fernandes, A. Fantoni, G. Lavareda, C. Nunes de Carvalho, R. Schwarz and M. Vieira An amorphous SiC/Si image photodetector with voltageselectable spectral response Thin Solid Films, 5-5, 6, pp.67-7

Voltage controlled optical filter Photocurrent (a) (A).3 NC p-i'(a-sic:h)-n-p-i(a-si:h)-n.35.

blue oth front and back diodes act as optical filters Front confining, diode Cuts respectively, the red Voltage the blue M. Vieira, P. Louro, controlled and the red M.

6 Voltage controlled optical filter Photocurrent (a) (A).3 NC p-i'(a-sic:h)-n-p-i(a-si:h)-n Hz ITO/pi (a-sic:h)n/ito/pi(a-si:h)n/ito Front cell ack cell -5V V Wavelength (nm) Wavelength (nm) - V -5 V V 3 V ack diode Cuts the blue oth front and back diodes act as optical filters Front confining, diode Cuts respectively, the red Voltage the blue M. Vieira, P. Louro, controlled and the red M. Fernandes, M.A. spectral optical carriers, Vieira, A. Fantoni response. while the green ones are absorbed and M. arata, Large area a-sic:h WDM devices for signal multiplexing across and both. demultiplexing in the visible spectrum, Thin Solid Films 57 (9), pp

7 Operation Principle Photocurrent (A) R G R Wavelength Division Demultiplexing RG V=-8V V=V G Time (ms) R&G& Wavelength Division Multiplexing V Experimental Design Work Area soma (-8V) V R(-8V) -8V G(-8) ### () ### R() ### G() ### Led R ### Led G ### Led ### ### ### InOx n (a-sic:h) i (a-si:h) nm p (a-sic:h) n (a-sic:h) - i (a-sic:h) nm p (a-sic:h) InOx Substrate G R ack diode Front diode M. Vieira, M. Fernandes, P. Louro, A. Fantoni, M. arata, M A Vieira, Multilayered a-sic:h device for Wavelength-Division (de)multiplexing applications in the visible spectrum Mater. Res. Soc. Symp. Proc. Volume 66 (8), pp.5-3 DOI:.557/PROC-66-A8-

8 Optical bias controlled optical filter Optical bias Channels Front diode ack diode Optical bias Optical bias p G i G TCO nm (a-sic:h) n p i nm (a-si:h) n TCO Optical bias GLASS Applied Voltage Photocurrent (na) No background Red background Green background lue background Violet background p-i'-n diode p-i-n diode V=-8V 5 Hz Wavelength (nm) Normalized Photocurrent C N35 R35 G35 35 Violtet 35 Photocurrent (na) ack optical bias p-i'-n diode p-i-n diode V=-8V 5 Hz Wavelength (nm) Normalized Photocurrent

Dynamics of electrical model with light biasing control Two stage active circuit Two

equivalent circuit i n Q I 4 I Two optical gate connections Light triggering

9 Dynamics of electrical model with light biasing control Two stage active circuit Two amplifying elements Two capacitive filter sections Q n n p p i n p I 3 I ac equivalent circuit i n Q I 4 I Two optical gate connections Light triggering Electrically programmable Light iasing Control M A Vieira, M. Vieira, M. Fernandes, A. Fantoni, P. Louro, M. arata, Amorphous and Polycrystalline Thin-Film Silicon Science and Technology 9, MRS Proceedings Volume 53, A8-3 Charge storage modelled by space-charge layer

State-space realization of the photonics active filters Dynamics of a parallel bucket connection How does the

? i, Input variables V V,, State variables Control matrix State-space realization of the equivalent circuit dt A

Fantoni, Double pin Photodiodes with two Optical Gate Connections for Light Triggering: A capacitive

10 State-space realization of the photonics active filters Dynamics of a parallel bucket connection How does the system input affect the state change?? i, Input variables V V,, State variables Control matrix State-space realization of the equivalent circuit dt A System matrix M. A. Vieira, M. Vieira, J. Costa, P. Louro, M. Fernandes, A. Fantoni, Double pin Photodiodes with two Optical Gate Connections for Light Triggering: A capacitive twophototransistor model in Sensors & Transducers Journal Vol., Special Issue, February, pp.96-. C Output matrix How does the current state affect the state change?? dv dt, RC RC Output variables it v, R RC R C R C v, C ( t) i C i t, ( t)

11 Optoelecronic simulator. Electrical model Input ackground Multiplexed channels (R signal (R G ) ) i (t) Simulator Dynamics of electrical model with light biasing control Vieira, M.A., Louro, P., Vieira, M., Fantoni, A., Steiger-Garção, A. Light-activated amplification in Si-C tandem devices: A capacitive active filter model IEEE SENSORS JOURNAL, VOL., NO. 6, JUNE pp DOI:.9/JSEN /C. v dt /R C v i(t) /R C i (t) /C. v /R C dt v /R /R C -/R C

12 Validation of the model MATLA as a programming environment and the four order Runge-Kutta method to solve the state equations Under negative dc. Without background Encoding: 8-levels Front Red background Encoding: 4-levels Photocurrent (A),,, 5 R R =.9 R = R G =.4 Red background no background) I R,,, Time (ms) I IGpi n I Gpin = =64 nm,5x -5,x -5 experimental (solid,5x lines) -5,x -5 5,x -6 simulated (symbols), IR ### IGR ### IG ### I ### Ion ### I ### -8V ### ### C Good agreement between experimental and simulated data M A Vieira, M. Vieira, M. Fernandes, A. Fantoni, P. Louro, M. arata, Amorphous and Polycrystalline Thin-Film Silicon Science and Technology 9, MRS Proceedings Volume 53, A8-3

..t8=t t=t 3 G R G (αrg<),,5 _G _G (αr>>) RG R _G R, RG,5 _G _G G, _,5 Time (ms) (αrr<<) Red ackground : The output waveform

13 Optical encoded data stream front red/without irradiation SiC tuneable background nonlinearity-based RG logic gates 4 = =64 nm Rdark Gdark dark Red blue green 5 5,,5,5,75,,5 Time (ms) Photocurrent ( A) Photocurrent ( A) 6bps... tn=n...t8=t t=t 3 G R G (αrg<),,5 _G _G (αr>>) RG R _G R, RG,5 _G _G G, _,5 Time (ms) (αrr<<) Red ackground : The output waveform becomes a main 4-level encoding (). Without optical bias is an 8-level encoding (3) to which it corresponds 8 different photocurrent thresholds. 3

Optical encoded data stream front/back violet irradiation SiC tuneable background nonlinearity-based RG logic gates V R,G, 3,5 3,,5,,5,,5 Violet background V pin V pin,,,5,,5,,5 Time

u) point AA Smoothing of Data3_ point AA Smoothing of Data3_E 5 point AA Smoothing of Data3_I 5 R G 4 R V G V 3 pin # R G # R # R # 5 point AA Smoothing of Data3_C 5 point AA Smoothing

14 Optical encoded data stream front/back violet irradiation SiC tuneable background nonlinearity-based RG logic gates V R,G, 3,5 3,,5,,5,,5 Violet background V pin V pin,,,5,,5,,5 Time (ms) V R pin V pin V pin V pin Front violet optical bias 8-level encoding ( 3 ) to which it corresponds 8 different photocurrent thresholds. Photocurrent (a.u) point AA Smoothing of Data3_ point AA Smoothing of Data3_E 5 point AA Smoothing of Data3_I 5 R G 4 R V G V 3 pin # R G # R # R # 5 point AA Smoothing of Data3_C 5 point AA Smoothing of Data3_G 5 point AA Smoothing of Data3_J pin,,5,,5,,5 Time (ms) G G (α V R >>) (α V G >) (α V ~) ack violet optical bias : The output waveform becomes a main 4-level encoding ( ). (α V >>) (α V G ~) (α V R <<) 4

Optical bias Conclusions Light-activated pi n/pin a-sic:h

simultaneous photodetection and self amplification of an

bias G R p TCO GLASS i nm (a-sic:h) n p i nm (a-si:h) Applied

external background it acts either as a shortor a long- pass

n TCO Gain ( R, G, ) 8 7 6 Photocurrent (A) 5 4 3 64nm, 35Hz.

5Hz 47nm, 35Hz. 47nm, 5Hz - V 4nm, 35Hz -5 V 4nm, 5Hz V 3 V.

15 Optical bias Conclusions Light-activated pi n/pin a-sic:h devices that combines the demultiplexing operation with the simultaneous photodetection and self amplification of an optical signal were designed, analyzed, validated and evaluated. Channels Front diode ack diode Experimental Design Optical bias G R p TCO GLASS i nm (a-sic:h) n p i nm (a-si:h) Applied Voltage Depending on the applied voltage and wavelength of the external background it acts either as a shortor a long- pass band filter or as a band-stop filter. n TCO Gain ( R, G, ) Photocurrent (A) nm, 35Hz.3 NC 64nm, 5Hz p-i'(a-sic:h)-n-p-i(a-si:h)-n 56nm, 35Hz 56nm, 5Hz 47nm, 35Hz. 47nm, 5Hz - V 4nm, 35Hz -5 V 4nm, 5Hz V 3 V. 75 Hz Wavelength 55 (nm) Wavelength (nm) Optoelectronic model Q p i I,I G n p n p I R,I G i Q n dv dt, RC RC it v, R RC R C R C t v, C ( t) i C, ( t)

Sensors & Transducers 2015 by IFSA Publishing, S. L.

Sensors & Transducers 2015 by IFSA Publishing, S. L. Sensors & Transducers, Vol. 8, Issue, January, pp. -9 Sensors & Transducers by IFSA Publishing, S. L. http://www.sensorsportal.com Photonic Amorphous Pi n/pin SiC Optical Filter Under Controlled Near UV