Introduction For new applications : fibre-radio systems

Présentation au sujet: "Introduction For new applications : fibre-radio systems"— Transcription de la présentation:

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

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

3 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 f = 11,4 GHz observed on the frequency response

4 The Dual Mode Laser structure
It is a sampled grating DFB laser Sampled grating structure P+ N+ elementary sampled grating 10 µm 80 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 Digital Optical Switch
No carrier injection BPM Modelling Carrier injection A Y junction unbalanced by injection of carriers

6 Variation de la puissance du signal hyper à 9GHz en fonction du courant injecté dans le DOS
5 10 15 20 25 30 35 40 -20 -40 P (dBm) -60 branche éteinte -80 branche commutée 58 dB ! -100 -120 I (mA) Département Hyperfréquences & Semiconducteurs

7 mesure du bruit de phase - modulation 9 GHz
0,00E+00 2,00E+05 4,00E+05 6,00E+05 8,00E+05 1,00E+06 1,20E+06 -10 -20 référence moyenne commutation moyenne P -30 -40 -50 -60 fréquence relative Département Hyperfréquences & Semiconducteurs

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

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

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

11 Experimental results Device fabricated at Opto+ (Alcatel)
11µm thick epitaxial structure (MOCVD) l=1.55µm : Max Resp=1.06A/W l=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 200°C / -10V / 1030 hours After Before

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

13 Réponses fréquencielles de MMF
2 -2 -4 -6 -8 -10 >80% des fibres intra -bâtiment < 300m 100m 500m réponse, dB 1km fréquence, GHz Département Hyperfréquences & Semiconducteurs