Electrical and Electronics Engineering PhD Thesis Defense by Muhammad Zakwan









Title: Meandering Loop Mirrors and Resonators in Silicon Integrated Photonics: Design, Fabrication, and Analysis


Speaker: Muhammad Zakwan


Time: August 23, 2017, 12:00


Place: ENG 208

Koç University

Rumeli Feneri Yolu

Sariyer, Istanbul

Thesis Committee Members:

Prof. Dr. İrşadi Aksun (Advisor, Koc University)

Prof. Dr. Ali Serpengüzel (Co-advisor, Koc University)

Prof. Dr. Özgür Müstecaplıoğlu (Koc University)

Assoc. Prof. Dr. Erdem Alaca (Koc University)

Asst. Prof. Dr. Ahmet Öncü (Boğaziçi University)

Prof. Dr. Alper Kiraz (Koc University)

Asst. Prof. Dr. Onur Ferhanoğlu (Istanbul Technical University)


Meandering loop mirrors (MLMs) and their associated resonators are designed, fabricated, and analyzed for silicon integrated photonics operation in the standard near-infrared (near-IR) telecommunication band. Directional couplers (DCs), MLMs, meandering resonators (MRs), antisymmetric MRs (AMRs), and symmetric MRs (SMRs) with symmetric and asymmetric MLMs are considered as a function of the DC length to scan the desired telecommunication band.

The silicon on insulator (SOI) platform is used to realize the devices in for single transverse electric (TE) mode polarization configuration of a strip waveguide. The photonic structures were designed based on numerical simulations using a photonics design kit and the resulting geometry of those photonic structures was incorporated into the photonic layout for fabrication by e-beam lithography. After the development stage in lithography, scanning electron microscope (SEM) images were taken followed by the cladding oxide deposition.

We analyzed the transmission spectral response of the MLM by performing numerical simulations and compared the results with the experimental measurements. We then analyzed the transmission spectra of more complex structures, such as MR, AMR, SMR, and their distributed feedback versions. The free spectral range, finesse, quality factor, and extinction ratio are deduced from these analyses.

The general response of a tunable mirror is observed for the MLMs. The results for the transmission intensities for the MR structures show a response similar to Fabry-Pérot resonators. The AMRs, apart from the more familiar Lorentzian, and inverse Lorentzian spectral responses, also show transmission spectra similar to the coupled resonator induced transparency. Such a variety of spectral responses makes the AMRs a candidate for designing optical switches, modulators, delay lines, and sensors. SMR is a higher order AMR. The SMR has a richer spectrum with Rabi split, Fano or Lorentzian lineshapes, which can be optimized for achieving spectral responses such as box-like filter shapes. MLMs and their associated resonators show promise as a novel integrated photonics platform for photonic lightwave circuit elements for optical communication, computation, and sensing.