Event

ANNOUNCEMENT:  Ph.D. Dissertation Defense

 

Title: Silicon Nitride Integrated Photonic Devices and Their Applications in Astronomy and Quantum Physics

The photonics technology has revolutionized the telecommunication industry in the past 40 years with the deployment of the undersea fiber-optic network. In recent years, with the maturity of silicon photonics technology, the integrated photonic platform is enabling more and more cutting-edge technologies, such as optical transceivers for data center connectivity, automotive LiDARs for self-driving vehicles, the next-generation astronomical instrumentation and nearterm photonic quantum computers, to name a few.

In this dissertation, I will first give an introduction of integrated photonics, and a brief overview of some novel applications and current trends. Next I will graphically show our methods for device fabrication and characterization, and then demonstrate a few integrated photonic devices implemented on Si3N4 material platforms, including Bragg grating, multimode interferometer, polarization beam splitter, and polarization rotator, with an in-depth discussion of their potential applications, principles of operation, simulation and experimental results.

I will then embark on a new chapter on arrayed waveguide gratings (AWGs), with emphasis on its application in integrated astronomical spectrometers. To obtain a continuous two-dimensional spectrum, cleaving at the output focal plane of the AWGis required. I will discuss and demonstrate a three-stigmatic-point AWG, which provides an elegant solution to the non-flat focal plane issue occurring in traditional Rowland AWGs. This work is a critical step towards the development of an efficient and miniaturized astronomical spectrograph for the upcoming extremely-large telescopes.

Next, I will introduce a one-dimensional nanobeam cavity enabled by a slow-light waveguide.
A cubic relation between the quality factor and the length of the cavity will be derived and experimental verification will be demonstrated. The current progress towards the investigation of the Purcell effect of this nanobeam cavity will be discussed, including the platform and the loss characterization of the deposited amorphous silicon material.

Finally, I will summarize the major conclusions from the previous chapters, and briefly discuss some future research directions extending the work in this thesis, including ultra-broadband polarization beam splitter, the development of an on-chip Bell state analyzer, and the design of a polarization-insensitive flat-focal-field spectrometer.