Electro-optically active ring devices for CMOS-compatible optoelectronics

• Main Author: Huang, Weibiao.
• Other Authors: Shum Ping
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/54625
• Institution: Nanyang Technological University

Lithium niobate (LiNbO3) has advantages of large electro-optic coefficients property and wide intrinsic bandwidth compared to traditional silicon as electro-optic material. A nested ring Mach–Zehnder interferometer (NR-MZI) intensity modulator on silicon-on-insulator has been proposed and investigated in this final year project. The modulator design and optimization consists of the following main stages. Firstly, the cross-section optimization has been implemented to realize high modulation efficiency and optimum power confinement in LiNbO3. With properly adjusting cross-section parameters, maximum confined optical power of 88.13% is achievable in the top LiNbO3 film. Also linear tapering technique has been developed on the modulator input/output cross-section design for device integration purpose and further optimization is carried out to realize an efficient and low-loss power transition within the waveguide. Then from the modulator layout view, the nested ring structure has been optimized using transfer matrix method. The performance dependence on structure dimensions are analyzed in detail. Three optimized designs are provided for industrial manufacture practice. The proposed optimization approaches in the project are also suitable for other types of ring based modulator design.