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1 Introduction For new applications : fibre-radio systems optically supplied microwave antennas There is a need for microwave photonic functions Emitters.

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Présentation au sujet: "1 Introduction For new applications : fibre-radio systems optically supplied microwave antennas There is a need for microwave photonic functions Emitters."— Transcription de la présentation:

1 1 Introduction For new applications : fibre-radio systems optically supplied microwave antennas There is a need for microwave photonic functions Emitters Optical switching matrixes Receivers microwave optical fibre

2 2 Axially coupled lasers : fabrication At IEMN and Tempere University of Technology Perot-Fabry lasers InP p + Substrate InPSI Active layer (MQW) InPp + GaInAs InPn + Fabrication on semi-insulating substrateFabrication on N+ substrate European TMR project

3 3 f = 11,4 GHz Axially coupled lasers: microwave experiments optical generation of a microwave signal (beating of the optical modes in a photodetector) tuning of the frequency with bias currents observed on the frequency response

4 4 The Dual Mode Laser structure It is a sampled grating DFB laser Sampled grating structure P+ N+ elementary sampled grating 10 µm80 µm N Contact P Contact 710 µm long device: - 7 DFB sections (10µm) - 8 FP sections (80 µm) - 2 end DFB sections (40 µm) It is also a DFB laser with a reduced coupling coefficient

5 5 Digital Optical Switch No carrier injection Carrier injection BPM Modelling A Y junction unbalanced by injection of carriers

6 6 Variation de la puissance du signal hyper à 9GHz en fonction du courant injecté dans le DOS I (mA) P (dBm) branche éteinte branche commutée Département Hyperfréquences & Semiconducteurs 58 dB !

7 7 Département Hyperfréquences & Semiconducteurs mesure du bruit de phase - modulation 9 GHz ,00E+002,00E+054,00E+056,00E+058,00E+051,00E+061,20E+06 fréquence relative P référence moyenne commutation moyenne

8 8 High power photodiodes : possible solutions 1.Travelling-Wave Photodetector –Increased absorption volume –Electrodes = 50 microwave line –Optical and microwave velocity matching 2.Uni Travelling Carrier Photodiode –Absorption in P+ GaInAs layer (no field) –Transit of photogenerated electrons by diffusion (base) and drift (collector)

9 9 P+ InP N+ InP nid GaInAs N+ GaInAsP - Good coupling to the fiber - One quaternary GaInAsP and InP layers - Specific waveguide half lens New concept : diluted multimode waveguide 1.3 µm or 1.55 µm

10 10 Typical behaviour of the optimized multimode diluted waveguide Photodetector behaviour Diluted multimode waveguide : optical behaviour Vertical scales dilated

11 11 Experimental results Device fabricated at Opto+ (Alcatel) 11µm thick epitaxial structure (MOCVD) =1.55µm : Max Resp=1.06A/W =1.30µm : Max Resp=0.86A/W -1 dB misalign. tolerance = 6.5 µm Influence of optical polarisation : lower than 0.1dB in all cases Cut-off frequency > Work in progress to get millimeter wave devices High reliability After Before 200°C / -10V / 1030 hours

12 12 Résultats des transmissions 32-QAM 1km MMF le câble coaxial (référence) le diagramme de constellation le diagramme de l oeil Département Hyperfréquences & Semiconducteurs

13 13 Réponses fréquencielles de MMF fréquence, GHz réponse, dB >80% des fibres intra -bâtiment < 300m km 500m 100m Département Hyperfréquences & Semiconducteurs


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