Browsing by Author "Durak, Kadir"
Now showing items 1-20 of 42
-
Adaptive MIMO free space optical communication systems
Free space optical (FSO) enjoys the high data rate of optical spectrum and have also the flexibility of RF links. FSO systems provide many advantages to the line of sight wireless communication technology. With the recent ... -
Adaptive multiple-input multiple-output (MIMO) techniques for visible light communications
Visible Light Communication (VLC) technology is a promising solution of wireless communication systems in beyond 5G communication networks, which provides low implementation cost, high energy efficiency, and high-speed ... -
Adaptive OFDM-based acoustic underwater transmission: system design and experimental verification
Sadeghi, Mohammad (2017-08)In this study, we design and implement an adaptive Underwater Acoustic (UWA) orthogonal frequency division multiplexing (OFDM) system employing adaptive modulation and transmit power. Recently, UWA communications gain more ... -
Attack to quantum cryptosystems through RF fingerprints from photon detectors
Durak, Kadir; Jam, Naser Chamani; Karamzadeh, S. (IEEE, 2022-03)The well-known RF penetration method is implemented on the quantum cryptosystems. In this study, RF radiations from the single photon detectors in a quantum key distribution system are intercepted. It was found that the ... -
Channel modeling for vehicular visible light communication
The demand for vehicular communication systems has increased since they are considered the key enabling technology for Intelligent Transportation Systems (ITSs). Vehicular communications allow information sharing between ... -
A compact circularly polarized monopulse slotted waveguide array for airborne applications
Nawaz, Wasim (2019-10-24)In modern radar and communication systems, high gain, high power capability and low-profile antenna systems are frequently utilized. In airborne and space borne applications, slotted waveguide antenna array is widely used ... -
Cryptographic security concerns on timestamp sharing via a public channel in quantum-key-distribution systems
Pahalı, Melis; Durak, Kadir; Tefek, U. (American Physical Society, 2022-07)Quantum-key-distribution protocols are known to be vulnerable against a side channel attack that exploits the time difference in detectors' responses used to obtain key bits. The recommended solution against this timing ... -
A custom-design atmospheric channel emulator for the performance evaluation of free space optical communication systems
Kebapçı, Burak (2017-08)The properties of atmospheric chamber and measurement methods that are used in this system are explained and analyzed in detail. We present our own custom design atmospheric channel emulator for FSO system evaluations and ... -
Design and construction of the fundamental tools for single atom experiments
Neutral atoms are one of the most promising systems for quantum information and quantum engineering, in general. Full and efficient control over cold atoms and their interactions with light has been a challenging and ... -
Design of vivaldi antenna operating in two frequency bands with distinct polarizations
This thesis presents a novel dual-polarized antenna design based on two orthogonally place Vivaldi antenna elements and are driven by a specially designed feeding network that splits incoming signal into two wherein one ... -
Development of a single-chip visible light communication receiver
The VLC has drawn the attention in the last decade, which is simply based on the data transmission over the visible light (400nm-700nm). It is considered as an alternative to RF-based technologies and offers unlicensed ... -
Development of an aerial interface for extraction of the electrodynamic fingerprints of the single-photon detectors
Karamzadeh, S.; Durak, Kadir; Jam, Naser Chamani; Rafiei, V.; Awad, B. (Wiley, 2021-12)In this study, a novel structure of semi array of antipodal Vivaldi antenna is designed to extract the RF radiations from the single-photon detectors in a quantum key distribution system. The proposed antenna covers a ... -
Down-conversion emission profile characterisation via camera
Kuniyil, Hashir Puthiyapurayil; Durak, Kadir (Optica Publishing Group, 2020-12-14)We present a method to improve the brightness and collection efficiency of the spontaneous parametric down-conversion source by monitoring the mode shape using camera and correcting it with collection optics. -
Effect of colour conversion layer on the optical and thermal efficiency of LED based liquid crystal displays
Bakan, Emrah (2018.05)In light-emitting diode (LED) lit liquid crystal displays (LCD), the colour gamut is related to the back-light unit (BLU) spectrum. The blue LED light is generally converted to green and red bands with phosphor mixtures. ... -
Effect of phase and spatial distinguishability of photon pairs on the entanglement fidelity
Kuniyil, Hashir Puthiyapurayil; Durak, Kadir (SPIE, 2021)Polarization entanglement based cryptography uses the photon pairs generated in a spontaneous parametric down-conversion process and guarantees the security through the violation of Bell's inequality. Certain experimental ... -
Effect of photon statistics on vacuum fluctuations based QRNG
Dandaşi, Abdulrahman; Özel, Helin; Hasekioglu, O.; Durak, Kadir (IOP Publishing, 2021-06)The speed of quantum random number generators (QRNGs) is a major concern for practical applications. In this work, we introduce scattering as a method to enhance the randomness characteristics of the entropy source. This ... -
Effects of photon statistics on quantum random number generators and photon detection efficiency
The effects of photon statistics on different quantum applications are explained in this thesis. There are mainly two sections: the first section focuses on the randomly bunched and coherently bunched photons' continuous ... -
Efficient coupling of down-converted photon pairs into single mode fiber
Kuniyil, Hashir Puthiyapurayil; Durak, Kadir (Elsevier, 2021-08-15)We present the analysis of the down-conversion emission profile from a critically phase-matched type-I nonlinear crystal. The emission profile of the down-conversion modes shows asymmetry in cylindrical coordinate system ... -
Entanglement demonstration on board a nano-satellite
Villar, A.; Lohrmann, A.; Bai, X.; Vergoossen, T.; Bedington, R.; Perumangatt, C.; Lim, H. Y.; Islam, T.; Reezwana, A.; Tang, Z.; Chandrasekara, R.; Sachidananda, S.; Durak, Kadir; Wildfeuer, C. F.; Griffin, D.; Oi, D. K. L.; Ling, A. (The Optical Society, 2020-07-20)Global quantum networks for secure communication can be realized using large fleets of satellites distributing entangled photon pairs between ground-based nodes. Because the cost of a satellite depends on its size, the ... -
Entanglement demonstration on board a nano-satellite
Villar, A.; Lohrmann, A.; Bai, X.; Vergoosen, T.; Bedington, R.; Perumangatt, C.; Lim, H. Y.; Islam, T.; Reezwana, A.; Tang, Z.; Chandrasekara, R.; Sachidananda, S.; Durak, Kadir; Wildfeuer, C. F.; Griffin, D.; Oi, D. K. L.; Ling, A. (Optica Publishing Group, 2020)Polarization entangled photon-pairs are generated and detected onboard a 3U CubeSat in low-Earth orbit that violate Bell’s inequality with a CHSH parameter of 2.60 ± 0.06. These results pave the way for space-based quantum ...
Share this page
