Doctoral Thesis Defense

Integrated Photonic Devices for Spectroscopic Chemical Detection

Derek M. Kita

Monday, December 16

2:00 – 3:00 pm

MIT Chipman Room (6-104)

A draft copy of the thesis will be available for review in room 6-107.

Chemical sensing systems realized with photonic components integrated on traditional semiconductor substrates have emerged as a promising technology for remote sensing applications that require low cost, low power consumption, light weight, small size, and high-performance.  In this thesis, I discuss methods and systems for practical implementations of chip-scale integrated photonic chemical sensors and spectrometers.  The work focuses on solutions to a variety of obstacles that have hindered real-world implementations of microphotonic chemical sensors.  First, a new chip architecture capable of acquiring high channel count, high resolution optical spectra is presented both theoretically and experimentally.  Next, evanescent field sensing using dielectric waveguides is studied theoretically and numerically, with a special emphasis on sensing performance in the presence of random, fabrication-induced waveguide sidewall roughness.  To experimentally realize photonic sensing systems, I developed a high-performance, quick-turn fabrication process for prototyping silicon nitride photonic integrated circuits with heaters, etched edge couplers, and opened sensing windows.  Using this fabrication process, I will present a successful experimental demonstration of a fiber-packaged waveguide-enhanced Raman spectroscopic sensor for real-time monitoring of liquids.

Thesis Supervisor

Professor Juejun Hu, Associate Professor, Materials Science and Engineering, Massachusetts Institute of Technology

Professor Lionel Kimerling, Thomas Lord Professor, Materials Science and Engineering, Massachusetts Institute of Technology

Thesis Committee

Professor Polina Anikeeva, Associate Professor, Materials Science and Engineering and Brain and Cognitive Sciences, Massachusetts Institute of Technology

Professor Yoel Fink, Professor, Materials Science and Engineering and Electrical Engineering and Computer Science, Massachusetts Institute of Technology