We are working on the development of the next-generation, Si and SiN-based photonic integrated circuit (PIC) components for quantum and 6G applications. These components, such as waveguides, delay lines, power splitters,  are the fundamental building blocks of the PICs for several ground-breaking applications, including quantum computing, neuromorphic computing, quantum communications, quantum sensing, and and THz/6G communications. We are using advanced design techniques, such as inverse design and deep learning, to achieve performance levels that cannot be obtained using classical design techniques in very small chip areas.

Projects: 

• Development of novel, on-chip optical components for time-domain, terahertz radio-on-fiber applications, TUBITAK 1001, 2023-2025.

Sample Publications: 

• A. O. Sakin, A. M. Demirtas, H. Kurt, M. Unlu, "Ultrafast pulse propagation time-domain dynamics in dispersive one-dimensional photonic waveguides, Nanophotonics, 0567, 2025.

• A. O. Sakin, H. Kurt, M. Unlu, "Ultra-miniaturized Bloch mode metasplitters for one-dimensional grating waveguides," Optics Letters, 50 (2), 610-613, 2025.

• A. O. Sakın, B. Akcay, A. C. Sonğur, M. Ünlü, "Periodic topology optimization‐based inverse design of slow-light in silicon nitride one-dimensional grating waveguides," SPIE Photonics Europe, Strasbourg, France, 7-11 Apr. 2024.

• A. O. Sakın, B. Akcay, H. A. Güneş, A. C. Sonğur, M. Ünlü, "Metamaterial-assisted power division: An inverse design study in 1D grating waveguides," META 2023 - The 13th International Conference on Metamaterials, Photonic Crystals and Plasmonics, Paris, France, 18-21 Jul. 2023.

• B. Akcay, H. A. Güneş, H. Kurt, M. Ünlü, "A fiber-to-waveguide, 1D grating coupler design using genetic algorithm for 1550 nm applications," SPIE Photonics Europe, Strasbourg, France, 3-7 Apr. 2022.

We are working on the development of the next-generation, superconducting microwave circuits for quantum computing, quantum communications, and quantum sensing. We are using advanced design techniques to achieve performance levels that cannot be obtained using classical design techniques.

Projects: 

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Sample Publications: 

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We are working on the development of the integrated thin film packaging technologies for the 94 GHz band and beyond.

Projects: 

• Thin-film packaging technology for beyond 60 GHz, ASELSAN REHIS, 2022-2024.

• Roadmap for the development of 2D scaled, 94 GHz antenna arrays,  ASELSAN REHIS, 2019-2020.

We are working on the development of the next-generation, reconfigurable THz sources and detectors. The sources and detectors are the most fundamental components for an integrated THz system. We are using different technologies, such as integrated optical and/or nanofabricated components, together with the terahertz photoconductive antennas and photomixers to obtain integrated THz systems with complex functionalities.

Projects: 

• Terahertz time-domain beam steering photoconductive antenna array  using on-chip optical phase control, TUBITAK 1001, 2020-2023.

• Beam steering, frequency reconfigurable terahertz photomixer array using nano-actuators, H2020 Marie Sklodowska Curie Program, Reintegration (RI) Grant, 2015-2017.

• Development  of  frequency  reconfigurable,  wideband,  high  radiation  resistance photomixers and photoconductive antennas for terahertz frequencies, TUBITAK 3501, 2014-2017.

Sample Publications: 

• K. Elmabruk, K. Demir, H. Altan, A. B. Sahin, and M. Unlu, "Time-domain characterization of the radiation pattern of the terahertz photoconductive antennas," Journal of Infrared, Millimeter, and Terahertz Waves, vol. 40, no. 6, Jun. 2019,

• K. Demir, AB Sahin, M. Unlu, “Design of a Frequency Reconfigurable, Terahertz Folded Antenna for Photomixers,” 2017 IEEE AP-S International Symposium and  USNC/URSI  National  Radio  Science  Meeting,  San Diego, California, USA, 9-14 July 2017.

•  K. Demir, H Bilgin, AB Sahin, M. Unlu, “Design of a frequency reconfigurable, terahertz antenna for photomixers,” Proc. International Conference on Infrared, Millimeter, and Terahertz Waves, Copenhagen, Denmark, Sep. 25-30, 2016.

We are working on the development of novel, surface wave supporting waveguides, which show similar behavior to the surface plasmon polariton (SPP) waves in the optical band. The advantage of the "spoof" SPP structures is that they provide very high confinement and low loss compared to the conventional planar waveguides in the THz band, which enables the highly integrated and high performance THz integrated circuits.

Projects: 

• Modelling, fabrication, and characterization of sSPP-based passive components and antennas for 1 THz and beyond integrated circuits operating 1 THz and beyond, TUBITAK 1001, 2020-2023.

• Reconfigurable surface plasmon polariton waveguides for terahertz frequencies, TUBITAK 1001, 2016-2019.

Sample Publications: 

• M. A. Unutmaz and M. Unlu, "Spoof Surface Plasmon Polariton Delay Lines for Terahertz Phase Shifters," Journal of Lightwave Technology, vol. 39, no. 10 , 3187-3192, May 2021.

• M. A. Unutmaz and M. Unlu, "Terahertz Spoof Surface Plasmon Polariton Waveguides: A Comprehensive Model with Experimental Verification," Nature Scientific Reports, vol. 9 , no. 1, 7616, May 2019.

• M. A. Unutmaz and M. Unlu, "accurate sSPP waveguide dielectric modelling," Electronics Letters, 53(21), 1391, Oct. 2017 (published as a featured article).

The nanofabricated components are enablers as the switching components for the THz band, as the state-of-the-art semiconductor technologies are not able to provide the desired performance for the frequencies beyond 1 THz. We are working on novel, nanofabricated and NEMS components for the reconfigurable operation beyond 1 THz.

Projects: 

• Development of higher order behavior models for NEMS and MEMS microstructures, TUBITAK 1001, 2017-2020 (PI: Prof. Hüsnü Dal, METU ME).

Sample Publications: 

• K. Demir and M. Unlu, "Miniature MEMS: Novel Key Components Toward Terahertz Reconfigurability," IEEE Journal of Microelectromechanical Systems, vol.29, no. 4, pp. 455-467, Aug. 2020 (published as a highlighted paper).

• M., Kandaz, H., Dal, M. Unlu, “Analysis of Gold Micro-Beams with Higher Order Continuum Theories,” 88th GAMM Annual Meeting, Germany, 6-10 March 2017.

We are working on the next-generation, CMOS integrated circuits for the beyond 5G applications.

Projects: 

• Preliminary design of an oscillator circuit for a 0.3 THz phase-locked loop, TUBITAK BILGEM, 2020-2020.