Integrated optical modulators based on photonic crystals

Gövdeli, Alperen
Photonic Crystals, artificial optical structures making manipulation of the light possible, have become a popular platform since their first development. Here, such optical components are studied theoretically and their unusual behaviors are utilized for integrated optics components. In particular, ability to change the effective index contribution of photonic crystals is exploited for the design of a low-voltage and area efficient integrated optical modulator. Variety of different aspects are compared between the existing on-chip modulator implementations and a novel approach based on photonic crystals is presented for further improvement. The proposed design is a Mach-Zehnder interferometer whose arms contain identical photonic crystal slabs. In order to create a relative phase along the arms of the interferometer, plasma dispersion effect is utilized where the novelty of the design comes from the source of the phase shift. Unlike the existing optical modulators in the literature, plasma dispersion effect is used to perform a band-to-band transition on the photonic crystal at the operation wavelength. According to the numerical analyses performed on photonic band diagram of photonic crystals, such transition provides a huge effective index change leading to a large phase shift, which results in the possibility of extremely small device sizes and low operation voltages for a proper intensity modulation at the output at extremely high speeds.


Flexible waveguides with amorphous photonic materials
Sarihan, Murat Can; Yilmaz, Yildirim Batuhan; Erdil, Mertcan; Aras, Mehmet Sirin; Yanik, Cenk; Wong, Chee Wei; Kocaman, Serdar (2019-01-01)
Amorphous photonic materials offer an alternative to photonic crystals as a building block for photonic integrated circuits due to their shared short-range order. By using the inherent disorder of amorphous photonic materials, it is possible to design flexible-shaped waveguides that are free from restrictions of photonic crystals at various symmetry axes. Effects of disorder on photonic crystal waveguide boundaries have examined before, and it is shown that flexible waveguides with high transmission are pos...
Tunable integrated optical modulator with dynamical photonic band transition of photonic crystals
GÖVDELİ, ALPEREN; Kocaman, Serdar (2019-01-01)
A Mach-Zehnder Interferometer based optical modulator composed of photonic crystals as phase shifters is presented. The switching process relies on the phase modulation along the arms of interferometer resulted from the photonic band shift of the photonic crystal regions. A small bulk index change leads to a large effective index difference between two arms of the interferometer and a small foot-print device can operate as a modulator. Presented MZI-based optical modulator is shown to have tunable bandwidth...
Integrated optical modulators with zero index metamaterials based on photonic crystal slab waveguides
Yildirim, Mustafa; GÖVDELİ, ALPEREN; Kocaman, Serdar (2019-01-01)
A novel integrated optical modulator design is presented using zero index metamaterial-based Mach-Zehnder Interferometer with photonic crystal phase shifters. The phase modulation relies on the shift between the photonic bandgaps having non-zero and zero effective refractive indices. A small change in the bulk index results in an effective index change between the arms of the MZI due to the disturbance of the band structure. Thus, such a structure provides a new approach for phase modulation on integrated o...
Erbium doped silicon photonic crystals for light sources and amplifiers
Vuckovic, Jelena; Makarova, Maria; Gong, Yiyang; Yerci, Selçuk; Li, Rui; Negro, Luca Dal (null; 2009-01-01)
We demonstrated enhancement of light emission from Er-doped silicon photonic crystal cavities, as well as cavity linewidth narrowing with increasing optical pump power at low temperature-an indication of differential gain in the system.
Hybrid metamaterial based structures for the development of a THz spatial light modulator
Chikhi, N.; Casini, R.; Papari, G. P.; Lisitskiy, M.; Tkachenko, V.; Altan, Hakan; Andreone, A. (2014-05-14)
We investigate new classes of artificial materials exhibiting unconventional properties in order to build novel devices operating in the Terahertz regime. The design, fabrication and electromagnetic characterization of tunable meta materials with unit cells based on Split Ring Resonators are presented. By incorporation of a nematic liquid crystal in the structure, we observe a frequency shift in the resonant response over 10% in bandwidth and more than 10 dB change in the signal absorption. We discuss how s...
Citation Formats
A. Gövdeli, “Integrated optical modulators based on photonic crystals,” M.S. - Master of Science, Middle East Technical University, 2018.