Ching-Ting Lee Institute of Microelectronics, Department of Electrical Engineering,

1. Integrated LiNbO3 Electrooptical Electromagnetic Field Sensor Ching-Ting Lee Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University

2. Introduction Principle and Configuration Experiments and Discussions Conclusions Outline

3. Introduction Application of electromagnetic wave EM WAVE

4. y z x Integrated LiNbO3 Electrooptical Electromagnetic Field Sensor with Micro Multi-antenna AZ4260 buffer layer Matching resistance SiO2 buffer layer Multi-annular antenna Polarization maintaining fiber Laser diode LiNbO3 crystal Single-mode fiber Mach-Zehnder modulator Spectrum analyzer Photodetector

5. Principle Mach-Zehnder modulator Modulator electrode Input waveguide Output waveguide LiNbO3 substrate

6. Z Y X LiNbO3 Crystal’s Electro-optic effect Ti-diffusion Waveguide Buffer layer r33 = 3110-12 m/V Modulator electrode Z-cut LiNbO3 substrate : optical phase L: length of electrode : wavelength d: gap between electrodes

7. Amplitude modulation optical output intensity optical output signal ½ t V modulator voltage electrical signal optical signal applied voltage Vi

8. On-off extinction ratio is 25.6dB V is about 4V Result 4V

9. y z x Integrated LiNbO3 Electrooptical Electromagnetic Field Sensor with Micro Multi-antenna AZ4260 buffer layer Matching resistance SiO2 buffer layer Multi-annular antenna Polarization maintaining fiber Laser diode LiNbO3 crystal Single-mode fiber Mach-Zehnder modulator Spectrum analyzer Photodetector

10. H E S • Experiments and Discussions Configuration of multi-annular antenna 30mm 20mm 10mm 14mm 12mm 10mm load 0.2mm

11. 0 -5 -10 -15 S11 Return loss(dB) 5.02 2.73 1.34 0 1 2 3 4 5 6 Frequency (GHz) Simulated resonant frequencyof multi-annular antenna

12. Advantages To obtain the frequency information To avoid the influence of the coaxial cable Microminiaturize

13. Anechoic chamber (500MHz to 6GHz) Emitter (Horn antenna) Test sensor Laser diode E Signal generator Photodetector Spectrum analyzer D=3m

14. H E S • Experiments and Discussions Configuration of multi-annular antenna 30mm 20mm 10mm 14mm 12mm 10mm load 0.2mm

15. 0 -5 -10 -15 S11 Return loss(dB) 5.02 2.73 1.34 0 1 2 3 4 5 6 Frequency (GHz) Simulated resonant frequencyof multi-annular antenna

16. Sensitivity factor Sf E(V/m) Sf  Voutput(V) 2.8 5.2 1.4

17. E-null configuration H E Load The sensitivity of the sensor Average minimum detectable field intensity 2.24mV/m

18. Y X Z Experimental Measurement of Electromagnetic Source Azimuth Using Electrooptical Electromagnetic Field Probe Vertical view Lateral view Sensor 60o 60o 60o 60o 60o 60o 90o Axis of sensor probe

19. Schematic diagram of the electrooptical electromagnetic field probe system Probe Sensor 1 Laser diode Sensor 2 Sensor 3 Photodetector Spectrum analyzer Photodetector Photodetector

20. Directional sensitivity pattern at 2.8 GHz H   Signal intensity (dBm) H E S

21. Conclusions • The response bandwidth of electromagnetic field sensor is successfully superposed by integrating micro multi-antenna. This is demonstrated that the center frequencies of response spectrum can be controlled by designing micro multi-antenna. • When the sensor probe axis was pointed toward the electromagnetic radiation source, the highest sensitivity was obtained. The variation of the sensitivity is within about0.4dB with rotating the probe around its axis. By using the electrooptical electromagnetic field probe system, the azimuth of the electromagnetic radiation source can be measured.

22. Thank you!