It's about the LiNbO3 based MZI Modulators

1. Lithium Niobate Based
MZI Modulators
-By Suresh Chand Jat
2015PWC5398
M.Tech (WOC)
MNIT Jaipur
Supervisor
Dr. M. Ravi Kumar
Assistant Professor
Dept. of ECE
MNIT Jaipur

2. Outlines
 Introduction to Lithium Niobate
 MZI Modulator
 MZI Performance Parameters
 MZI Design Parameters
 MZI layout
 Simulation Results
 Conclusion

3. Introduction
to Lithium
Niobate
(LiNbO3)
 Lithium niobate is a colourless solid insoluble in
water. It has a trigonal crystal system, which
lacks inversion symmetry and displays
ferroelectricity, Pockels
effect, piezoelectric effect, photoelasticity
and nonlinear optical polarizability.
 Lithium niobate has negative
uniaxial birefringence which depends slightly
on the stoichiometry of the crystal and on
temperature. It is transparent for wavelengths
between 350 and 5200 nanometers

4. LiNbO3
Properties

5. Main
Advantages
of LiNbO3
 LiNbO3 is an electroptic material
 Components compacts.
 Active components ( modulators …).
 Low driving voltage.
 High data rate (20-40 GHz )
 Good compatibility with optical fibres
 Pigtailling : relatively easy butt coupling ).
 Wafer fabrication.
 Light fabrication technology (<5 mask layers ).…..

6. Mach-Zehnder
Interferometer
(MZI)
Modulator
 In optical switching, induced phase shift by applied
voltage can be converted to an amplitude variation by
using an interferometer
 Interferometer is a device that interferes two waves of
the same frequency but different phase
 Compared to Directional coupler MZI offers a higher
modulation speed for a given drive voltage and
provides a higher extinction ratio.

7. MZI
Performance
Parameters
Insertion loss
Excess Loss
Extinction Ratio
SwitchingVoltage

8. MZI Design
Parameters
 Software - OptiBPM
 Crystal –Lithium Niobate
 Crystal cut-Z
 Propagation Direction-Y
 Dielectric Material –Air
 Profile –TiLiNbO3
 Wafer Dimension
 Length-33000 um
 Width- 100 um
 Electrode Length- 11500 -21500 um
 OperatingWavelength – 1.3 um
 SwitchingVoltage- 6.75V

9. MZI Layout

10. Simulation
Results
Optical Field when Electrode-2Voltage is 0 volt

11. Simulation
Results
Refractive index When Elecrode-2 Voltage is 0 volt

12. Simulation
Results
Field and RI graphWhen Elecrode-2 Voltage is 0 volt

13. Simulation
Results
Optical Field When Elecrode-2 Voltage is 6.75 volt

14. Simulation
Results
Refractive index When Elecrode-2 Voltage is 6.75 volt

15. Simulation
Results
Field and RI graphWhen Elecrode-2 Voltage is 6.75 volt

16. Conclusion
 MZI is widely used optical device performs the optical modulation
and switching operations.
 Operate at 20-40 GHz
 It can be possible to design MZI for visible band
 I will try to improve one of the MZI performance parameter like
insertion loss or switching voltage.

17. THANKYOU