Research • Research Areas

Photonic Integrated Circuits and Integrated Optical Sensors:

Photonic Integrated Circuits (PIC) research at Sabancı University Electronics Engineering Program focuses mainly on the development of semiconductor based photonics devices for WDM Fiber Optic Telecommunications Networks and integrated optical sensing applications. The major area of interest are the design, fabrication, and characterization of low loss, fast tunable filters, tunable add/drop MUX/DEMUX, photonic switches, and EO modulators.
Two different architectures are used for the realization of these devices. One technology utilizes hybrid integrated polymer and semiconductor waveguides. The other technology uses optical microresonator based devices. Microresonators, with their small size and ability to perform various wavelength selective optical functions, are very strong candidates as the building blocks for next generation WDM PICs. The modification and optimization of the WDM devices are studied with the goal of utilizing them as integrated biological or chemical sensors. The realization of PICs are done by photonic integration or photonic/electronic integration of different devices on the same platform (substrate). This is very desirable for improved functionality and efficiency, as well as reduced size and cost. The PIC Group focus on the development of novel processing technologies and components for the realization of PICs. Current research involves a substrate-removed epitaxial layer transfer technique (which enables the processing of both sides of the epi) and the development of I/O mode converters, optical interconnects, among others.
Different polymer, GaAs and InP/InGaAsP microresonator structures.
A further research area, the development of nanoparticle based photonic devices, is carried out in collaboration with the Material Science Program. This research involves the synthesis and manipulation of nanoparticles and quantum dots as well as the design and fabrication of polymer/ nanoparticle based photonic devices (on-chip UV sources, wavelength converters, etc).

Faculty: Cem Ozturk

Recent/Relevant Papers:

-- Total internal reflection mirror based InGaAsP ring resonators integrated with optical amplifiers, Kim, D.G., Shin, J.H., Ozturk, C., Yi, J.C., Chung, Y., Dagli, N., IEEE Photonics Technology Letters, 17(9), 1899-1902, 2005.

-- T-rail electrodes for substrate-removed low voltage, high speed GaAs/AlGaAs electro-optic modulators, Shin, J.H., Ozturk, C., Sakamoto, S.R., Chiu, Y.J., Dagli, N., IEEE Transaction on Microwave Theory and Techniquess, 53(2), 636-644, 2005.

-- Filtering characteristics of hybrid Integrated polymer and compound semiconductor waveguides, Ozturk, C., Huntington, A., Aydinli, A., Byun, Y.T., Dagli, N., IEEE Journal of Lightwave Technology, 20(8), 153-1536, 2002.

-- Polymer/compound semiconductor hybrid micro resonators with very wide free spectral range, Ozturk, C., Chiu, Y. J., Dagli, N., Proc. IEEE/LEOS 15th annual meeting, pp. 744-745, Glasgow, Scotland, UK, November 2002.

-- Coupled polymer waveguides and substrate removed GaAs waveguides as tunable filters, Ozturk, C., Dagli, N., Proc. OSA/IPR Trends in Optics and Photonics, 45, pp. 240-242, Washington, DC, USA, July 2000.

Optical Tweezers:

Optical tweezers refer to the non-invasive manipulation of small particles by using a focused laser beam. The unique configuration used allows the use of very low laser powers, hence tweezing action can be performed on live cells without causing any damage to them. Computer-generated arbitrary trapping paths and time-shared trapping patterns are successfully demonstrated. Currently evanescent wave structures are explored for manipulating nanometer size particles.

Surface Plasmon Resonance Based Devices:

Surface Plasmon Resonance (SPR) is a light induced collective oscillation of electrons in a thin film of a metal. There has been numerous applications of this phenomenon including bio-sensing and chemical sensing. In addition to sensor development, researchers at Sabancı University's Photonics Group are exploring the increased photoluminescence due to SPR enhanced evanescent waves. They have shown that SPR can be used as a highly sensitive optical microphone or pressure sensor.

3D Holographic Imaging:

In this area, researchers at the Photonics Group investigate the 3D imaging of objects in transmissive or reflective configuration. Holograms are recorded on a CCD camera and the calculations are performed on the computer. Various signal processing algorithms for increasing the image quality are explored as well as the transformation methods to rotate the created image on the screen.

Photonic Crystal Sensors:

Photonic Crystals are artificially created periodic structure that modify the propagation of electromagnetic waves. In a unique setup, researchers in the Group has shown that photonic crystals can be used as highly sensitive background refractive index sensors, orders of magnitude more sensitive than the existing systems. This system can be expanded to other sensor applications rather easily. Currently a US patent is applied for.

Matter Wave Interferometry:

In recent years there has been significant activity in research and development of high sensitivity accelerometers and gyroscopes using matter waves using Sagnac effect. However in all of these conventional devices the resultant phase shift is independent of the wave velocity. It has been found that using the Aharonov-Bohm effect, it is possible to use slower waves to enhance the sensitivity of matter wave interferometers enormously. Experimental investigation of this theoretical work is under way.

Faculty: Meric Ozcan

Recent/Relevant Papers:

-- High sensitivity rotation sensing with atom interferometers using Aharonov-Bohm effect, Ozcan, M., Proc. SPIE, San Jose, CA, Feb 2006.

-- A compact, automated and long working distance optical tweezer system, Ozcan, M., Onal, C., Akatay, A., J. Mod. Opt., 53, 357-364, 2006.

-- High sensitivity displacement sensing with surface plasmon resonance, Ozcan, M., Proc. SPIE, San Diego,CA, Aug 2005.

-- Influence of electric potentials on atom interferometers: Increased rotation sensitivity, Ozcan, M., J. Appl. Phys., 83, 6185-6186, 1998.