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Novel Tunable Photonic True Time Delay Devices for Ultra-wideband Beamforming for mmWave Communications

Paul, Banaful
http://rave.ohiolink.edu/etdc/view?acc_num=osu1668515268205691

Abstract Details

2022, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
Ever-increasing demand for ubiquitous mobile connectivity, transformed our communication systems from wireless systems using Morse code to modern 5th-generation mobile networks of today. Currently, the 5G technology harnessing mm-Wave bands is poised to usher an era of networking and connectivity with immense possibilities. All-electronic beamforming and beam steering of phased antenna arrays are key requirements for mm- Wave systems due to the fundamental limitation of higher propagation loss of such high frequencies. Although traditional phased array antennas have been in use at the infrastructure level (e.g. mobile towers with smart beam-forming arrays), they are often narrow band and conventional beamforming techniques are bulky, energy hungry, and expensive to integrate into mobile consumer devices. The research goals presented here aim to address this problem by utilizing a unique, slow-wave photonic waveguide structure to realize a tunable, integrated, and inherently ultra-wideband true-time-delay (TTD) device that can operate over the entire mm-Wave band and enable much-needed broadband 5G connectivity for compact beam-forming transceiver architectures. We present a simple photonic waveguide structure that exhibits light propagation modes with vanishing group velocity via mode degeneracy. Precise tuning of device topology enables the stationary inflection point (SIP) dispersion leading to the frozen mode and a TTD device, particularly suitable for ultra-wide-band beamforming for millimeter wave phased arrays. The structure consists of three Si ridge waveguides in proximity to periodic gaps introduced in the outer waveguides to create a band gap. The proposed multiply-coupled waveguide is CMOS compatible with an extremely-small footprint of only about 14 μm and more resilient to fabrication uncertainties compared to the previously studied structures. Simulation results show a transmission of 70% of the incident wave is achievable for the frozen mode at 1.55 μm (193.6 THz) wavelength into the integrated waveguide. This unique mode also enables unprecedented frequency-independent bandwidth of about 0.5 THz for RF-mmW–THz beamforming. Continuous tunability of this frozen-mode stemmed slow wave device is presented exploiting two modulation techniques, namely, the plasma-modulation and the thermo-optic modulation. Plasma modulation enables about 7.5 ps/V tuning whereas for thermo-optic, it is about 0.72 ps/mW. Both of these techniques are amenable to on-chip integration. More importantly, the proposed frozen-mode TTD device can also be exploited for several other applications. As also proposed in this dissertation, forming a cavity around the Si ridges can enable the TTD device as a label-free photonic biosensing device. We demonstrate via simulations that the proposed device can achieve a sensitivity of 78.95 nm/RIU for sensing Hemoglobin molecules in blood sample. Moreover, we envision that the presented TTD device can also be adopted as an optical buffer and data synchronizer with a capability of buffering of 15 bits for a 1 Tbit/s data transmission system in an integrated optical network by providing 15 ps of delay within a 14 μm space.
Niru K. Nahar (Advisor)
Fernando L. Teixeira (Committee Member)
Kubilay Sertel (Committee Member)
153 p.
Electrical Engineering

Recommended Citations

Citations

  • Paul, B. (2022). Novel Tunable Photonic True Time Delay Devices for Ultra-wideband Beamforming for mmWave Communications [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1668515268205691

    APA Style (7th edition)

  • Paul, Banaful. Novel Tunable Photonic True Time Delay Devices for Ultra-wideband Beamforming for mmWave Communications. 2022. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1668515268205691.

    MLA Style (8th edition)

  • Paul, Banaful. "Novel Tunable Photonic True Time Delay Devices for Ultra-wideband Beamforming for mmWave Communications." Doctoral dissertation, Ohio State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=osu1668515268205691

    Chicago Manual of Style (17th edition)

osu1668515268205691
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