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Pulsed Free Space Photonic Vector Network Analyzers

Faridi, Fahd Rushd (2023)
Pulsed Free Space Photonic Vector Network Analyzers.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00024075
Dissertation, Erstveröffentlichung, Verlagsversion

Kurzbeschreibung (Abstract)

Terahertz (THz) radiation (0.1–10 THz) has demonstrated great significance in a wide range of interdisciplinary applications due to its unique properties such as the capacity to penetrate optically opaque materials without ionizing effect, superior spatial resolution as compared to the microwave domain for imaging or ability to identify a vast array of molecules using THz fingerprinting. Advancements in generation and detection techniques, as well as the necessities of application-driven research and industry, have created a substantial demand for THz-range devices and components. However, progress in the development of THz components is hampered by a lack of efficient and affordable characterization systems, resulting in limited development in THz science and technology. Vector Network Analyzers (VNAs) are highly sophisticated well-established characterization instruments in the microwave bands, which are now employed in the lower end of the THz spectrum (up to 1.5 THz) using frequency extender modules. These modules are extremely expensive, and due to the implementation of hollow metallic waveguides for their configuration, they are narrowband, requiring at least six modules to achieve a frequency coverage of 0.2–1.5 THz. Moreover, they are susceptible to problems like material losses, manufacturing and alignment tolerances etc., making them less than ideal for fast, broadband investigation. The main objective of this thesis is to design a robust but cost-effective characterization system based on a photonic method that can characterize THz components up to several THz in a single configuration. To achieve this, we design architectures for the Photonic Vector Network Analyzer (PVNA) concept, incorporating ErAs:In(Al)GaAs-based photoconductive sources and ErAs:InGaAs-based photoconductive receivers, driven with a femtosecond pulsed laser operating at 1550 nm. The broadband photonic devices replace narrowband electronic ones in order to record the Scattering (S)-parameters in a free space configuration. Corresponding calibration and data evaluation methods are also developed. Then the PVNAs are configured, and their capabilities are validated by characterizing various THz components, including a THz isolator, a distributed Bragg Reflector, a Split-Ring Resonator array and a Crossed-Dipole Resonator (CDR) array, in terms of their S-parameters. The PVNAs are also implemented to determine the complex refractive index or dielectric permittivity and physical thickness of several materials in the THz range. Finally, we develop an ErAs:In(Al)GaAs-based THz transceiver and implement it in a PVNA configuration, resulting in a more compact setup that is useful for industrial applications. The feasibility of such systems is also verified by characterizing several THz components. The configured systems achieve a bandwidth of more than 2.5 THz, exceeding the maximum attainable frequency of the commercial Electronic Vector Network Analyzer (EVNA) extender modules. For the 1.1-1.5 THz band, the dynamic range of 47-35 dB (Equivalent Noise Bandwidth (ENBW) = 9.196 Hz) achieved with the PVNA is comparable to the dynamic range of 45-25 dB (ENBW = 10 Hz) of the EVNA. Both amplitude and phase of the S-parameters, determined by the configured PVNAs, are compared with simulations or theoretical models and showed excellent agreement. The PVNA could discern multi-peak and narrow resonance characteristics despite its lower spectral resolution (∼3-7 GHz) compared to the EVNA. By accurately determining the S-parameters of multiple THz components, the transceiver-based PVNA also demonstrated its exceptional competence. With huge bandwidth and simpler calibration techniques, the PVNA provides a potential solution to bridge the existing technological gap in THz-range characterization systems and offers a solid platform for THz component development, paving the way for more widespread application of THz technologies in research and industry.

Typ des Eintrags: Dissertation
Erschienen: 2023
Autor(en): Faridi, Fahd Rushd
Art des Eintrags: Erstveröffentlichung
Titel: Pulsed Free Space Photonic Vector Network Analyzers
Sprache: Englisch
Referenten: Preu, Prof. Dr. Sascha ; Taylor, Dr. Zachary
Publikationsjahr: 2023
Ort: Darmstadt
Kollation: xii, 155 Seiten
Datum der mündlichen Prüfung: 17 Februar 2023
DOI: 10.26083/tuprints-00024075
URL / URN: https://tuprints.ulb.tu-darmstadt.de/24075
Kurzbeschreibung (Abstract):

Terahertz (THz) radiation (0.1–10 THz) has demonstrated great significance in a wide range of interdisciplinary applications due to its unique properties such as the capacity to penetrate optically opaque materials without ionizing effect, superior spatial resolution as compared to the microwave domain for imaging or ability to identify a vast array of molecules using THz fingerprinting. Advancements in generation and detection techniques, as well as the necessities of application-driven research and industry, have created a substantial demand for THz-range devices and components. However, progress in the development of THz components is hampered by a lack of efficient and affordable characterization systems, resulting in limited development in THz science and technology. Vector Network Analyzers (VNAs) are highly sophisticated well-established characterization instruments in the microwave bands, which are now employed in the lower end of the THz spectrum (up to 1.5 THz) using frequency extender modules. These modules are extremely expensive, and due to the implementation of hollow metallic waveguides for their configuration, they are narrowband, requiring at least six modules to achieve a frequency coverage of 0.2–1.5 THz. Moreover, they are susceptible to problems like material losses, manufacturing and alignment tolerances etc., making them less than ideal for fast, broadband investigation. The main objective of this thesis is to design a robust but cost-effective characterization system based on a photonic method that can characterize THz components up to several THz in a single configuration. To achieve this, we design architectures for the Photonic Vector Network Analyzer (PVNA) concept, incorporating ErAs:In(Al)GaAs-based photoconductive sources and ErAs:InGaAs-based photoconductive receivers, driven with a femtosecond pulsed laser operating at 1550 nm. The broadband photonic devices replace narrowband electronic ones in order to record the Scattering (S)-parameters in a free space configuration. Corresponding calibration and data evaluation methods are also developed. Then the PVNAs are configured, and their capabilities are validated by characterizing various THz components, including a THz isolator, a distributed Bragg Reflector, a Split-Ring Resonator array and a Crossed-Dipole Resonator (CDR) array, in terms of their S-parameters. The PVNAs are also implemented to determine the complex refractive index or dielectric permittivity and physical thickness of several materials in the THz range. Finally, we develop an ErAs:In(Al)GaAs-based THz transceiver and implement it in a PVNA configuration, resulting in a more compact setup that is useful for industrial applications. The feasibility of such systems is also verified by characterizing several THz components. The configured systems achieve a bandwidth of more than 2.5 THz, exceeding the maximum attainable frequency of the commercial Electronic Vector Network Analyzer (EVNA) extender modules. For the 1.1-1.5 THz band, the dynamic range of 47-35 dB (Equivalent Noise Bandwidth (ENBW) = 9.196 Hz) achieved with the PVNA is comparable to the dynamic range of 45-25 dB (ENBW = 10 Hz) of the EVNA. Both amplitude and phase of the S-parameters, determined by the configured PVNAs, are compared with simulations or theoretical models and showed excellent agreement. The PVNA could discern multi-peak and narrow resonance characteristics despite its lower spectral resolution (∼3-7 GHz) compared to the EVNA. By accurately determining the S-parameters of multiple THz components, the transceiver-based PVNA also demonstrated its exceptional competence. With huge bandwidth and simpler calibration techniques, the PVNA provides a potential solution to bridge the existing technological gap in THz-range characterization systems and offers a solid platform for THz component development, paving the way for more widespread application of THz technologies in research and industry.

Alternatives oder übersetztes Abstract:
Alternatives AbstractSprache

Terahertz (THz)-Strahlung (0,1–10 THz) hat aufgrund ihrer einzigartigen Eigenschaften große Bedeutung für ein breites Spektrum interdisziplinärer Anwendungen erlangt. Dazu zählen die Fähigkeit, optisch undurchsichtige Materialien ohne ionisierende Wirkung zu durchdringen, eine bessere räumliche Auflösung als Mikrowellenstrahlung für die Bildgebung und die Fähigkeit, verschiedenste Moleküle mit Hilfe von THz-Fingerabdrücken zu identifizieren. Fortschritte bei Quellen und Detektoren beschleunigt durch die Erfordernisse der anwendungsorientierten Forschung und Industrie haben zu einer erheblichen Nachfrage nach Geräten und Komponenten im THz-Bereich geführt. Der Fortschritt bei der Entwicklung von THz-Komponenten wird jedoch durch einen Mangel an effizienten und erschwinglichen Messgeräten behindert, was zu einer begrenzten Entwicklung in der THz-Wissenschaft und -Technologie führt. Vektorielle Netzwerkanalysatoren (VNAs) sind hochentwickelte und etablierte Charakterisierungsinstrumente für den Mikrowellenbereich, die nun auch im unteren Bereich des THz- Spektrums (bis zu 1,5 THz) unter Verwendung von Frequenzerweiterungsmodulen eingesetzt werden. Diese Module sind extrem teuer und aufgrund der Verwendung von Hohlleitern schmalbandig, so dass mindestens sechs Module erforderlich sind, um eine Frequenzabdeckung von 0,2 bis 1,5 THz zu erreichen. Außerdem sind die Bänder und insbesondere deren Tausch anfällig für Fertigungs- und Ausrichtungstoleranzen, was sie für schnelle, Untersuchungen mit großer Frequenzabdeckung nicht gerade ideal macht. Das Hauptziel dieser Arbeit ist es, ein robustes, aber kostengünstiges Messgerät auf der Grundlage einer photonischen Methode zu entwickeln, das THz-Komponenten bis zu mehreren THz mit Hilfe eines einzigen Systems charakterisieren kann. Um dies zu erreichen, haben wir Architekturen für photonische vektorieller Netzwerkanalysatoren (PVNA) entwickelt, die ErAs:In(Al)GaAs photoleitende Quellen und ErAs:InGaAs photoleitende Empfänger enthalten, welche mit einem gepulsten Femtosekundenlaser bei 1550 nm betrieben werden. Diese breitbandigen Komponenten ersetzen die schmalbandigen elektronischen Komponenten. Passende Kalibrierungs- und Datenauswertungsmethoden wurden ebenfalls entwickelt. Anschließend werden die PVNAs konfiguriert und ihre Fähigkeiten durch die Charakterisierung verschiedener THz-Komponenten wie einen THz-Isolator, einen Bragg-Reflektor, ein Ringresonator-Array und ein gekreuztes Dipolresonator-Array im Hinblick auf ihre Streuparameter (S-Parameter) validiert. Die PVNAs wurden auch zur Bestimmung des komplexen Brechungsindexes oder der Dielektrizitätskonstante und der physikalischen Dicke verschiedener Materialien im THz-Bereich eingesetzt. Abschließend entwickelten wir einen ErAs:In(Al)GaAs-basierten THz-Transceiver und implementierten ihn in einer PVNA- Konfiguration. Dies führt zu einem kompakteren Aufbau, der für industrielle Anwendungen nützlich ist. Die Funktionalität solcher Systeme wurde auch durch die Charakterisierung verschiedener THz-Komponenten verifiziert.

Deutsch
Status: Verlagsversion
URN: urn:nbn:de:tuda-tuprints-240756
Sachgruppe der Dewey Dezimalklassifikatin (DDC): 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau
Fachbereich(e)/-gebiet(e): 18 Fachbereich Elektrotechnik und Informationstechnik
18 Fachbereich Elektrotechnik und Informationstechnik > Institut für Mikrowellentechnik und Photonik (IMP)
18 Fachbereich Elektrotechnik und Informationstechnik > Institut für Mikrowellentechnik und Photonik (IMP) > THz Bauelemente und THz Systeme
TU-Projekte: EC/H2020|713780|Pho-T-Lyze
Hinterlegungsdatum: 22 Jun 2023 12:03
Letzte Änderung: 26 Jun 2023 08:27
PPN:
Referenten: Preu, Prof. Dr. Sascha ; Taylor, Dr. Zachary
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: 17 Februar 2023
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