Abstract
Silicon photonics stands at the forefront of technological innovation, seamlessly merging the worlds of electronics and optics on a single silicon chip, creating significant advancements in high-speed communication, data processing, and energy-efficient computing. Ongoing research is focused on achieving efficient phase shifting, high-speed modulation, compatibility with CMOS processing, on-chip laser integration, and cost-effective packaging. All of these are critical areas driving advancements in the field. In this work we make contributions to improvements in each of these areas. Efficient Phase Shifters - Ultra efficient thermo-optic phase shifters: We achieved wafer-scale compatible thermally-isolated phase shifters that operate >15 times (Pπ = 1.2 mW) more efficiently than standard thermo-optic devices. Micro-Transfer printed thin-film lithium niobate (TFLN) phase shifters: We have demonstrated thin film lithium niobate (TFLN) coupon fabrication and transfer printing process to achieve high-speed electro-optic modulation at visible wavelengths which find critical applications in quantum photonic research. With our current process using the Xceleprint micro transfer printing (MTP) system, we are able to transfer ring-shaped 100 μm radius coupons that have 13 μm width and 100 nm thickness and create electro-optic modulators at visible wavelengths that operate at 400 MHz (measurement limited) with a tuning efficiency of 2.5 pm/V. MEMS Phase Shifters: To achieve a large neff tuning within a compact design footprint, we present the design, modelling, fabrication and testing of low-voltage silicon photonic MEMs phase shifters. With devices fabricated at RIT, we are able to demonstrate wafer-scale release of the MEMs structures and get Vπ of 7 V. Laser integration using photonic wire bonding (PWB): Integrating III-V lasers onto silicon photonic integrated circuits remains challenging due to material mismatch, CMOS process compatibility, strict alignment tolerances, and packaging requirements such as thermal management and reliable optical coupling. III-V on- silicon lasers are commonly achieved through direct epitaxial growth (monolithic integration), wafer bonding (heterogeneous integration), and die bonding or pick-and-place (hybrid integration). Some approaches limit pre-integration testing of the individual laser dies, require pristine bond quality surfaces and tight process control at wafer scale. In this work, an on-chip integrated DFB laser is demonstrated using the Vanguard photonic wire bonder to create 3D polymerized waveguides for efficient optical coupling. Single-mode lasing is achieved by implementing a second photonic wire bond in the assembly. This creates an adiabatic transition of the optical mode and helps mitigate interface reflections. This improvement is verified through a series of circulator measurements. In addition, thermal wavelength tuning up to 4 nm is demonstrated by using a glass substrate to improve heat confinement in the assembly compared to conventional silicon.
Publication Date
12-16-2025
Document Type
Dissertation
Student Type
Graduate
Degree Name
Microsystems Engineering (Ph.D.)
Department, Program, or Center
Microsystems Engineering
College
Kate Gleason College of Engineering
Advisor
Stefan Preble
Advisor/Committee Member
Karl Hirschman
Advisor/Committee Member
Parsian Mohseni
Recommended Citation
Deenadayalan, Venkatesh, "Advanced Photonic Integration and Packaging: Efficient Phase Shifters, Micro-Transfer Printed Modulators, and Photonic Wire-Bonded On-Chip Lasers" (2025). Thesis. Rochester Institute of Technology. Accessed from
https://repository.rit.edu/theses/12400
Campus
RIT – Main Campus
Comments
This thesis has been embargoed. The full-text will be available on or around 12/16/2026.