ching-ting lee institute of microelectronics, department of electrical engineering,

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National Cheng Kung University

Ching-Ting Lee

Institute of Microelectronics,

Department of Electrical Engineering,


Integrated LiNbO3 Electrooptical Electromagnetic Field Sensor

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Outline

• Introduction

• Principle and Configuration

• Experiments and Discussions

• Conclusions

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Application of electromagnetic waveApplication of electromagnetic wave

IntroductionIntroduction

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Integrated LiNbO3 Electrooptical Electromagnetic Field Sensor with Micro Multi-antenna

Multi-annular antenna

Laserdiode

Spectrum analyzer

xyz

Photodetector

LiNbO3

crystalSingle-mode fiber

Matching resistance

SiO2

buffer layer

Polarizationmaintainingfiber

AZ4260buffer layer

Mach-Zehnder modulator

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Mach-Zehnder modulatorMach-Zehnder modulator

LiNbO3 substrate

Modulator electrode

Output waveguide

Input waveguide

PrinciplePrinciple

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Ti-diffusionWaveguide

Modulator electrode

Z-cut LiNbO3 substrate

zeeeez Enrnnnn 3332

1

r33 = 3110-12 m/V

Lnz

2

zz EL

rn

333

: optical phase L: length of electrode: wavelengthd: gap between electrodes

Y

Z

X

Bufferlayer

dEV dLrn

Vz

333

LiNbOLiNbO3 3 Crystal’s Electro-optic effectCrystal’s Electro-optic effect

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Vi

V

optical output intensity

½

Amplitude modulationAmplitude modulation

applied voltage

modulator voltage

t

optical output signal

electrical signal

optical signal

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ResultResult

4V

• On-off extinction ratio is 25.6dB• V is about 4V

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Integrated LiNbO3 Electrooptical Electromagnetic Field Sensor with Micro Multi-antenna

Multi-annular antenna

Laserdiode

Spectrum analyzer

xyz

Photodetector

LiNbO3

crystalSingle-mode fiber

Matching resistance

SiO2

buffer layer

Polarizationmaintainingfiber

AZ4260buffer layer

Mach-Zehnder modulator

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load

30mm

20mm

12mm 14mm

10mm

10mm

0.2mm

Experiments and DiscussionsExperiments and Discussions

Configuration of multi-annular antennaConfiguration of multi-annular antenna

H E

S

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Simulated resonant frequencySimulated resonant frequency of multi-annular antennaof multi-annular antenna

S11

1.34

5.022.73

Frequency (GHz)

Return loss (dB)

0 1 2 3 4 5 6

0

-5

-10

-15

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AdvantagesAdvantages

To obtain the frequency information

To avoid the influence of the coaxial cable

Microminiaturize

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Emitter (Horn antenna)

E

D=3m

Test sensor

Anechoic chamber (500MHz to Anechoic chamber (500MHz to 6GHz)6GHz)

Laser diode

Photodetector

Spectrum analyzer

Signal generator

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load

30mm

20mm

12mm 14mm

10mm

10mm

0.2mm

Experiments and DiscussionsExperiments and Discussions

Configuration of multi-annular antennaConfiguration of multi-annular antenna

H E

S

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Simulated resonant frequencySimulated resonant frequency of multi-annular antennaof multi-annular antenna

S11

1.34

5.022.73

Frequency (GHz)

Return loss (dB)

0 1 2 3 4 5 6

0

-5

-10

-15

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Sensitivity factor SSensitivity factor Sff

E(V/m) Sf Voutput(V)

0 1 2 3 4 5 670

80

90

100

110

120

Sen

siti

vit

y f

act

or (d

B)

Frequency (GHz)

1.42.8 5.2

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The sensitivity of the sensorThe sensitivity of the sensor

Average minimum detectable

field intensity 2.24mV/m

-70 -60 -50 -40 -30 -20 -10 0-70

-60

-50

-40

-30

-20

-10

0 1.4 GHz 2.8 GHz 5.2 GHz

Normalized electric field intensity (dB)

Nor

mal

ized

indu

ced

volt

age

(dB

)

0

1

2

3

4

5

6

7

8

Ele

ctri

c fi

eld

inte

nsit

y (V

/m)

Load

H

E-nullconfiguration

E

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Experimental Measurement of Electromagnetic Source Azimuth Using Electrooptical

Electromagnetic Field Probe

Vertical view

90o

60o

60o

60o

Y

X

Z

Axis of sensor probe

Lateral view

60o

60o

60o

Sensor

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Probe

Sensor 2

Sensor 3

Schematic diagram of the electrooptical Schematic diagram of the electrooptical electromagnetic field probe systemelectromagnetic field probe system

Spectrum analyzer

Photodetector

Photodetector

Photodetector

Sensor 1

Laser diode

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Signal intensity (dBm)

Directional sensitivity pattern at 2.8 GHzDirectional sensitivity pattern at 2.8 GHz

E

H

S

H

0

30

60

90

120

150

180

210

240

270

300

330

-64

-62

-60

-58

-56

-64

-62

-60

-58

-56

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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 0.4 dB 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.

ConclusionsConclusions

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Thank you!

ching-ting lee institute of microelectronics, department of electrical engineering,

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