KOÇ UNIVERSITY PHYSICS SEMINAR
|Speaker:||Emir Salih Mağden, Koç University|
|Title:||Ultra-Broadband Silicon Photonic Filtering|
|Date:||February 19, 2019|
|Cookie & Tea:||ENG Z15 14:15|
|Place:||ENG Z15 (not the usual classroom)|
The field of integrated optics has seen immense growth in the last three decades during which many components including lasers, filters, multiplexers,modulators, and detectors have been demonstrated. Of these devices, optical filters are one of the most important and widely used building blocks in photonic systems. Many applications in optics utilize interferometric on-chip filters enabled by the silicon photonics technology including microring resonators, Bragg or arrayed waveguide gratings, contra-directional couplers, and photonic crystal filters for in-band filtering. On the other hand, with recent advances in integrated supercontinuum and second/high-harmonic generation on-chip handling of ultra-broadband optical signals is becoming increasingly important. Being able to arbitrarily and effectively filter and combine hundreds-of-nanometers-wide signals is crucial for on-chip integration of key functionalities including f − 2f and f − 3f interferometry, spectroscopy, and wideband wavelength-division multiplexing. Yet, limited optical bandwidths of the aforementioned interferometric filters typically preclude their use in applications that require octave-wide bandwidths. In this talk, we address the aforementioned challenges in optical filters by presenting the theory, design approach, and experimental results for broadband, low-loss, integrated, 1×2 port, transmissive dichroic filters that simultaneously achieve single-cutoff operation, octave-wide optical bandwidths, and sharp filter roll-offs. This performance is enabled by the concept of “spectrally selective waveguides”, and achieved through mode evolution by adiabatic transitions. Filters with cutoffs around 1550 and 2100nm are fabricated on a silicon-on-insulator platform with standard complementary metal-oxide-semiconductor processes. A filter roll-off of 2.82 dB/nm is achieved while maintaining ultra-broadband operation. This new class of nanophotonic dichroic filters can lead to new paradigms in on-chip communications, sensing, imaging, optical synthesis, and display applications.
Short Bio: Emir Salih Mağden is an Assistant Professor of Electrical & Electronics Engineering at Koç University, and is the director of Photonic Architecture Laboratories (pal.ku.edu.tr). He has received his B.S. in Electrical Engineering from Tufts University, and his S.M. and Ph.D. in Electrical Engineering and Computer Science from Massachusetts Institute of Technology. His graduate studies focused on the development and optimization of integrated photonic devices and systems for broadband optical signal generation, stabilization, and manipulation. His current research interests include adaptive integrated photonics, CMOS-compatible amplifiers and lasers, and ultra-broadband on-chip optical networks for communications, sensing, and optical data handling applications. He is a recent recipient of the TUBITAK Career Development Grant and the Science Academy’s Young Scientist Award (BAGEP 2018), and is a member of OSA and IEEE.