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The experiments were performed using an ultrafast laser generating pulses with durations between 430 fs and 560 fs at a central wavelength of 1030 nm. Pulses with an energy of either 263 µJ or 150 µJ were coupled into the fiber at average powers of either 48 W or 95 W, respectively. In both cases, the transmittance through the fiber was measured to exceed 85\\% without detectable distortion of the temporal pulse shapes or damage to the fiber.", "issn" : "1432-0649", "doi" : "10.1007/s00340-025-08540-w", "bibtexKey": "Kühlthau.2025.Efficient" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/243f30def99d172b4424dae3989b9e13e/ifsw", "tags" : [ "myown","laser","peer","UltrashortPulse","glassfiber","fiberbeamdelivery","waveguide" ], "intraHash" : "43f30def99d172b4424dae3989b9e13e", "interHash" : "fae834e87dd9455f5353b29ba6b14143", "label" : "Efficient delivery of sub-ps laser pulses with pulse energies exceeding 100 µJ at average powers of up to 95 W through a hollow-core fiber", "user" : "ifsw", "description" : "", "date" : "2025-08-25 13:30:48", "changeDate" : "2025-08-25 13:30:48", "count" : 2, "pub-type": "article", "journal": "Applied Physics B", "year": "2025", "url": "https://doi.org/10.1007/s00340-025-08540-w", "author": [ "Tim Kühlthau","Bowen Chen","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Tim", "last" : "Kühlthau"}, {"first" : "Bowen", "last" : "Chen"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "volume": "131","number": "9","pages": "177","abstract": "We report on the efficient delivery of sub-picosecond laser pulses with high peak and high average powers through a home-made 7.5 m long tubular inhibited-coupling guiding hollow-core photonic-crystal fiber (IC-HCPCF). The experiments were performed using an ultrafast laser generating pulses with durations between 430 fs and 560 fs at a central wavelength of 1030 nm. Pulses with an energy of either 263 µJ or 150 µJ were coupled into the fiber at average powers of either 48 W or 95 W, respectively. In both cases, the transmittance through the fiber was measured to exceed 85\\% without detectable distortion of the temporal pulse shapes or damage to the fiber.", "issn" : "1432-0649", "doi" : "10.1007/s00340-025-08540-w", "bibtexKey": "Kühlthau.2025.Efficient" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/22181ee0e5c5c3b68889ca15191db9372/tkuhlthau", "tags" : [ "fiberbeamdelivery","glassfiber","myown","polarization","waveguide" ], "intraHash" : "2181ee0e5c5c3b68889ca15191db9372", "interHash" : "d42dfec5a50d0ee2ffb6c78e6929438b", "label" : "Polarization-maintaining hollow-core fibers for radially and azimuthally polarized light", "user" : "tkuhlthau", "description" : "", "date" : "2025-06-30 10:25:19", "changeDate" : "2025-06-30 10:25:19", "count" : 2, "pub-type": "presentation", "year": "2025", "url": "", "author": [ "Tim Kühlthau","Bowen Chen","Götz Kleem","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Tim", "last" : "Kühlthau"}, {"first" : "Bowen", "last" : "Chen"}, {"first" : "Götz", "last" : "Kleem"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "eventtitle" : "CLEO Europe 2025", "venue" : "Munich, Bavaria, Germany", "language" : "English", "refid" : "859299227", "eventdate" : "23 - 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27 June 2025", "bibtexKey": "Kühlthau.2025.Polarization" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2f94d9dce8c4d3fb726529afdf3bb2654/tkuhlthau", "tags" : [ "FiberBeamdelivery","GlassFiber","OpticalElements","UltrashortPulse","Waveguide","myown" ], "intraHash" : "f94d9dce8c4d3fb726529afdf3bb2654", "interHash" : "ae7b0cb28390acad5d292381339d6802", "label" : "Development of hollow-core fibers at the IFSW", "user" : "tkuhlthau", "description" : "", "date" : "2024-06-11 11:58:52", "changeDate" : "2024-06-11 11:58:52", "count" : 2, "pub-type": "presentation", "year": "2024", "url": "", "author": [ "Tim Kühlthau","Bowen Chen","Götz Kleem","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Tim", "last" : "Kühlthau"}, {"first" : "Bowen", "last" : "Chen"}, {"first" : "Götz", "last" : "Kleem"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "eventtitle" : "SLT 2024", "venue" : "Stuttgart, Germany", "language" : "English", "eventdate" : "04 - 06 June 2024", "bibtexKey": "kuhlthau2024development" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2f94d9dce8c4d3fb726529afdf3bb2654/ifsw", "tags" : [ "myown","OpticalElements","UltrashortPulse","GlassFiber","FiberBeamdelivery","Waveguide" ], "intraHash" : "f94d9dce8c4d3fb726529afdf3bb2654", "interHash" : "ae7b0cb28390acad5d292381339d6802", "label" : "Development of hollow-core fibers at the IFSW", "user" : "ifsw", "description" : "", "date" : "2024-06-11 11:58:52", "changeDate" : "2024-06-11 11:58:52", "count" : 2, "pub-type": "presentation", "year": "2024", "url": "", "author": [ "Tim Kühlthau","Bowen Chen","Götz Kleem","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Tim", "last" : "Kühlthau"}, {"first" : "Bowen", "last" : "Chen"}, {"first" : "Götz", "last" : "Kleem"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "eventtitle" : "SLT 2024", "venue" : "Stuttgart, Germany", "language" : "English", "eventdate" : "04 - 06 June 2024", "bibtexKey": "kuhlthau2024development" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/285f4395e41131e432670479ca3546161/ifsw", "tags" : [ "myown","myOwn","sapphire","waveguide","resonant" ], "intraHash" : "85f4395e41131e432670479ca3546161", "interHash" : "edae042b7d07eb7cb498e9fa456ee864", "label" : "Improved thermal performances of resonant reflection waveguide grating structure", "user" : "ifsw", "description" : "", "date" : "2024-05-08 14:11:43", "changeDate" : "2024-05-08 14:49:47", "count" : 5, "pub-type": "presentation", "journal": "Conference on Lasers and Electro-Optics/Europe (CLEO/Europe 2023) and European Quantum Electronics Conference (EQEC 2023)","booktitle": "Conference on Lasers and Electro-Optics/Europe (CLEO/Europe 2023) and European Quantum Electronics Conference (EQEC 2023)","publisher":"Optica Publishing Group", "year": "2023", "url": "https://opg.optica.org/abstract.cfm?URI=CLEO_Europe-2023-ca_9_2", "author": [ "Ayoub Boubekraoui","Danish Bashir","Georgia Mourkioti","Jacob. I. Mackenzie","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Ayoub", "last" : "Boubekraoui"}, {"first" : "Danish", "last" : "Bashir"}, {"first" : "Georgia", "last" : "Mourkioti"}, {"first" : "Jacob. I.", "last" : "Mackenzie"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan Abdou", "last" : "Ahmed"} ], "pages": "ca_9_2","abstract": "We present the intra-cavity characterization (within an Yb:YAG thin-disk oscillator) of a single-layer resonant waveguide grating (RWG) using a crystalline material (namely Sapphire) as substrate. The operating principle of the present device is the same as in \\[1\\]. It offers high reflectivity > 99\\% with a narrow spectral bandwidth of typically <1 nm FWHM for a given polarization and angle of incidence. Commonly single-layer dielectric waveguide gratings are based on sub-wavelength grating integrated with a high-index waveguide (such as Ta2O5 or Nb2O5) coated on a fused silica substrate. Often, they suffer from heating caused by the absorption in the waveguide layer, in addition to the relatively low thermal conductivity of the substrate, thus limiting their applications in high average power lasers. In the present contribution, we report on a RWG composed of a Ta2O5 waveguide layer coated on a structured sapphire substrate with better thermal performance at high average laser power (i.e., at high-power densities on the grating surface). The designed device consists of a single Ta2O5 layer of 200 -- 235 nm thickness deposited upon a binary grating with a period of 515 nm and a groove depth of 120 nm etched into a sapphire (Al2O3) substrate \\[2\\]. The RWG was designed to operate for TE polarization at 1030 nm and an angle of incidence of ~ 10°.The suitable choice of substrate material offers a thermal conductivity that is an order of magnitude higher than fused silica. Before its implementation in the laser cavity, the fabricated sample was first characterized in a spectroscopic setup to measure its reflectivity for both TE and TM polarizations. At the central wavelength of our laser i.e. 1030 nm, the reflectivity for TE and TM polarizations were measured to be rte $=$ 99.2 ± 0.2\\% a RTM $=$ 8 ± 0.2\\%, respectively.", "bibtexKey": "Boubekraoui:23" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2d42363d202f0a162f9d108331b279e5f/ifsw", "tags" : [ "myOwn","sapphire","waveguide","resonant" ], "intraHash" : "d42363d202f0a162f9d108331b279e5f", "interHash" : "edae042b7d07eb7cb498e9fa456ee864", "label" : "Improved thermal performances of resonant reflection waveguide grating structure", "user" : "ifsw", "description" : "", "date" : "2024-05-08 14:10:52", "changeDate" : "2024-05-08 14:10:52", "count" : 5, "pub-type": "inproceedings", "journal": "Conference on Lasers and Electro-Optics/Europe (CLEO/Europe 2023) and European Quantum Electronics Conference (EQEC 2023)","booktitle": "Conference on Lasers and Electro-Optics/Europe (CLEO/Europe 2023) and European Quantum Electronics Conference (EQEC 2023)","publisher":"Optica Publishing Group", "year": "2023", "url": "https://opg.optica.org/abstract.cfm?URI=CLEO_Europe-2023-ca_9_2", "author": [ "Ayoub Boubekraoui","Danish Bashir","Georgia Mourkioti","Jacob. I. Mackenzie","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Ayoub", "last" : "Boubekraoui"}, {"first" : "Danish", "last" : "Bashir"}, {"first" : "Georgia", "last" : "Mourkioti"}, {"first" : "Jacob. I.", "last" : "Mackenzie"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan Abdou", "last" : "Ahmed"} ], "pages": "ca_9_2","abstract": "We present the intra-cavity characterization (within an Yb:YAG thin-disk oscillator) of a single-layer resonant waveguide grating (RWG) using a crystalline material (namely Sapphire) as substrate. The operating principle of the present device is the same as in \\[1\\]. It offers high reflectivity > 99\\% with a narrow spectral bandwidth of typically <1 nm FWHM for a given polarization and angle of incidence. Commonly single-layer dielectric waveguide gratings are based on sub-wavelength grating integrated with a high-index waveguide (such as Ta2O5 or Nb2O5) coated on a fused silica substrate. Often, they suffer from heating caused by the absorption in the waveguide layer, in addition to the relatively low thermal conductivity of the substrate, thus limiting their applications in high average power lasers. In the present contribution, we report on a RWG composed of a Ta2O5 waveguide layer coated on a structured sapphire substrate with better thermal performance at high average laser power (i.e., at high-power densities on the grating surface). The designed device consists of a single Ta2O5 layer of 200 -- 235 nm thickness deposited upon a binary grating with a period of 515 nm and a groove depth of 120 nm etched into a sapphire (Al2O3) substrate \\[2\\]. The RWG was designed to operate for TE polarization at 1030 nm and an angle of incidence of ~ 10°.The suitable choice of substrate material offers a thermal conductivity that is an order of magnitude higher than fused silica. Before its implementation in the laser cavity, the fabricated sample was first characterized in a spectroscopic setup to measure its reflectivity for both TE and TM polarizations. At the central wavelength of our laser i.e. 1030 nm, the reflectivity for TE and TM polarizations were measured to be rte $=$ 99.2 ± 0.2\\% a RTM $=$ 8 ± 0.2\\%, respectively.", "bibtexKey": "Boubekraoui:23" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/285f4395e41131e432670479ca3546161/a.boubekraoui", "tags" : [ "myown","resonant","sapphire","waveguide" ], "intraHash" : "85f4395e41131e432670479ca3546161", "interHash" : "edae042b7d07eb7cb498e9fa456ee864", "label" : "Improved thermal performances of resonant reflection waveguide grating structure", "user" : "a.boubekraoui", "description" : "", "date" : "2024-05-08 14:09:13", "changeDate" : "2024-05-08 14:49:47", "count" : 5, "pub-type": "presentation", "journal": "Conference on Lasers and Electro-Optics/Europe (CLEO/Europe 2023) and European Quantum Electronics Conference (EQEC 2023)","booktitle": "Conference on Lasers and Electro-Optics/Europe (CLEO/Europe 2023) and European Quantum Electronics Conference (EQEC 2023)","publisher":"Optica Publishing Group", "year": "2023", "url": "https://opg.optica.org/abstract.cfm?URI=CLEO_Europe-2023-ca_9_2", "author": [ "Ayoub Boubekraoui","Danish Bashir","Georgia Mourkioti","Jacob. I. Mackenzie","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Ayoub", "last" : "Boubekraoui"}, {"first" : "Danish", "last" : "Bashir"}, {"first" : "Georgia", "last" : "Mourkioti"}, {"first" : "Jacob. I.", "last" : "Mackenzie"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "pages": "ca_9_2","abstract": "We present the intra-cavity characterization (within an Yb:YAG thin-disk oscillator) of a single-layer resonant waveguide grating (RWG) using a crystalline material (namely Sapphire) as substrate. The operating principle of the present device is the same as in \\[1\\]. It offers high reflectivity > 99\\% with a narrow spectral bandwidth of typically <1 nm FWHM for a given polarization and angle of incidence. Commonly single-layer dielectric waveguide gratings are based on sub-wavelength grating integrated with a high-index waveguide (such as Ta2O5 or Nb2O5) coated on a fused silica substrate. Often, they suffer from heating caused by the absorption in the waveguide layer, in addition to the relatively low thermal conductivity of the substrate, thus limiting their applications in high average power lasers. In the present contribution, we report on a RWG composed of a Ta2O5 waveguide layer coated on a structured sapphire substrate with better thermal performance at high average laser power (i.e., at high-power densities on the grating surface). The designed device consists of a single Ta2O5 layer of 200 -- 235 nm thickness deposited upon a binary grating with a period of 515 nm and a groove depth of 120 nm etched into a sapphire (Al2O3) substrate \\[2\\]. The RWG was designed to operate for TE polarization at 1030 nm and an angle of incidence of ~ 10°.The suitable choice of substrate material offers a thermal conductivity that is an order of magnitude higher than fused silica. Before its implementation in the laser cavity, the fabricated sample was first characterized in a spectroscopic setup to measure its reflectivity for both TE and TM polarizations. At the central wavelength of our laser i.e. 1030 nm, the reflectivity for TE and TM polarizations were measured to be rte $=$ 99.2 ± 0.2\\% a RTM $=$ 8 ± 0.2\\%, respectively.", "bibtexKey": "Boubekraoui:23" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/27b244b05cbc2ce743380e933fdece872/ifsw", "tags" : [ "myown","Design","OpticalElements","GlassFiber","FiberBeamdelivery","Modeling","Waveguide" ], "intraHash" : "7b244b05cbc2ce743380e933fdece872", "interHash" : "4ae570e0d7cc69f5f1bd3383da21668b", "label" : "Design, Production, and Characterization of a Large-Mode Area Tubular Inhibited-Coupling Guiding Hollow-Core Fiber with Low Dispersion", "user" : "ifsw", "description" : "", "date" : "2024-05-08 13:34:41", "changeDate" : "2024-05-08 13:34:42", "count" : 3, "pub-type": "presentation", "booktitle": "2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","publisher":"IEEE", "year": "2023", "url": "http://dx.doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10231834", "author": [ "Tim Kühlthau","Bowen Chen","Götz Kleem","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Tim", "last" : "Kühlthau"}, {"first" : "Bowen", "last" : "Chen"}, {"first" : "Götz", "last" : "Kleem"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "pages": "1-1","abstract": "Since the first demonstration [1], hollow-core fibers have been considered as the only presently known solution for the flexible delivery of beams of high peak-power ultrafast lasers. This is achieved thanks to a low power overlap between the core-guided modes and the fiber glass cladding (in the range of 10−4 to 10−6) [2]. For the beam delivery in production systems, it is necessary for the fibers not to alter the pulse characteristics during propagation. Besides nonlinear effects and dispersion caused by the gas inside the fiber core, which can be mitigated by filling the fiber core with noble gases or applying a vacuum to the core, the chromatic dispersion of the fiber itself is a main contributor to changes in the pulse duration. In general, a larger fiber core leads to a reduced chromatic dispersion.", "venue" : "Munich, Germany", "isbn" : "979-8-3503-4599-5", "language" : "English", "eventdate" : "26 - 30 June 2023", "eventtitle" : "2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)", "issn" : "2833-1052", "doi" : "10.1109/CLEO/Europe-EQEC57999.2023.10231834", "bibtexKey": "Kühlthau.2023.Design" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2395434d1f3dd410a8c01682fbe0e257c/florianbienert", "tags" : [ "Diode","Laser","Lithography","Volume","Waveguide","diffraction","gratings","infrared","lasers","myown","operation","peer" ], "intraHash" : "395434d1f3dd410a8c01682fbe0e257c", "interHash" : "265a3944d166013fa6cf5dc2700ad689", "label" : "Diode stabilization with dual duty-cycle resonant waveguide grating", "user" : "florianbienert", "description" : "", "date" : "2023-12-08 14:52:53", "changeDate" : "2023-12-08 14:52:53", "count" : 4, "pub-type": "conference", "journal": "Laser Congress 2023 (ASSL, LAC)","booktitle": "Laser Congress 2023 (ASSL, LAC)","publisher":"Optica Publishing Group", "year": "2023", "url": "https://opg.optica.org/abstract.cfm?URI=ASSL-2023-AW3A.5", "author": [ "Florian Bienert","Fangfang Li","Marina Fetisova","Petri Karvinen","Markku Kuittinen","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Florian", "last" : "Bienert"}, {"first" : "Fangfang", "last" : "Li"}, {"first" : "Marina", "last" : "Fetisova"}, {"first" : "Petri", "last" : "Karvinen"}, {"first" : "Markku", "last" : "Kuittinen"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "pages": "AW3A.5","abstract": "We present for the first time the experimental demonstration of resonant waveguide grating (RWG) employing a dual duty-cycle profile for the stabilization of a 50 W laser diode emitting in the near-infrared spectral range.", "bibtexKey": "Bienert:23" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/27b244b05cbc2ce743380e933fdece872/tkuhlthau", "tags" : [ "Design","FiberBeamdelivery","GlassFiber","Modeling","OpticalElements","Waveguide","myown" ], "intraHash" : "7b244b05cbc2ce743380e933fdece872", "interHash" : "4ae570e0d7cc69f5f1bd3383da21668b", "label" : "Design, Production, and Characterization of a Large-Mode Area Tubular Inhibited-Coupling Guiding Hollow-Core Fiber with Low Dispersion", "user" : "tkuhlthau", "description" : "", "date" : "2023-12-08 10:38:57", "changeDate" : "2024-05-08 13:34:41", "count" : 3, "pub-type": "presentation", "booktitle": "2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)","publisher":"IEEE", "year": "2023", "url": "http://dx.doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10231834", "author": [ "Tim Kühlthau","Bowen Chen","Götz Kleem","Thomas Graf","Marwan Abdou Ahmed" ], "authors": [ {"first" : "Tim", "last" : "Kühlthau"}, {"first" : "Bowen", "last" : "Chen"}, {"first" : "Götz", "last" : "Kleem"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Marwan", "last" : "Abdou Ahmed"} ], "pages": "1-1","abstract": "Since the first demonstration [1], hollow-core fibers have been considered as the only presently known solution for the flexible delivery of beams of high peak-power ultrafast lasers. This is achieved thanks to a low power overlap between the core-guided modes and the fiber glass cladding (in the range of 10−4 to 10−6) [2]. For the beam delivery in production systems, it is necessary for the fibers not to alter the pulse characteristics during propagation. Besides nonlinear effects and dispersion caused by the gas inside the fiber core, which can be mitigated by filling the fiber core with noble gases or applying a vacuum to the core, the chromatic dispersion of the fiber itself is a main contributor to changes in the pulse duration. In general, a larger fiber core leads to a reduced chromatic dispersion.", "venue" : "Munich, Germany", "isbn" : "979-8-3503-4599-5", "language" : "English", "eventdate" : "26 - 30 June 2023", "eventtitle" : "2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)", "issn" : "2833-1052", "doi" : "10.1109/CLEO/Europe-EQEC57999.2023.10231834", "bibtexKey": "Kühlthau.2023.Design" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/20e59c7a6aa6ee1ceb12b34236204896c/ingmarkallfass", "tags" : [ "207","220","230","50","GHz","GHz;Power","GHz;frequency","MMIC;coplanar","Waveguide;Module","amplifier","amplifier;HEMT;Coplanar","amplifier;eight-way","amplifiers;Power","amplifiers;power","circuits;Bandwidth;Frequency;MMICs;Indium","combiners;power","combining;amplifier","coplanar","coupler;Dolph-Chebychev","electron","faults;MMIC;Power","generation;Coplanar","mW;frequency","mobility","module;solid-state","on-chip","phosphide;HEMTs;Circuit","power","state","technology;HEMT","to","transformer;power","transistors;power","transistors;tandem","waveguide","waveguides;Solid","waveguides;high" ], "intraHash" : "0e59c7a6aa6ee1ceb12b34236204896c", "interHash" : "77a774c4398f74d47c7804afbf41172e", "label" : "A 50 mW 220 GHz power amplifier module", "user" : "ingmarkallfass", "description" : "", "date" : "2022-11-04 11:48:46", "changeDate" : "2022-11-04 10:48:46", "count" : 1, "pub-type": "inproceedings", "booktitle": "2010 IEEE MTT-S International Microwave Symposium", "year": "2010", "url": "", "author": [ "V. Radisic","K. M. K. H. Leong","X. Mei","S. Sarkozy","W. Yoshida","P. Liu","J. Uyeda","R. Lai","W. R. Deal" ], "authors": [ {"first" : "V.", "last" : "Radisic"}, {"first" : "K. M. K. H.", "last" : "Leong"}, {"first" : "X.", "last" : "Mei"}, {"first" : "S.", "last" : "Sarkozy"}, {"first" : "W.", "last" : "Yoshida"}, {"first" : "P.", "last" : "Liu"}, {"first" : "J.", "last" : "Uyeda"}, {"first" : "R.", "last" : "Lai"}, {"first" : "W. R.", "last" : "Deal"} ], "pages": "45-48","abstract": "In this paper, a 220 GHz solid-state power amplifier (SSPA) module is presented. Eight-way on-chip power combining is used to achieve a saturated output power ≥ 50 mW over a 217.5 to 220 GHz bandwidth, representing a significant increase in SSPA output power at this frequency compared to prior state of the art. The amplifier MMIC is implemented in coplanar waveguide (CPW) technology and uses sub 50 nm InP HEMT transistors. Two levels of power combining, a 2:1 tandem coupler and a 4:1 Dolph-Chebychev transformer, are realized in CPW. The module demonstrates ≥ 11.5 dB small signal gain from 207 to 230 GHz. Saturated output power ≥ 40 mW was measured from 216 to 222.5 GHz.", "date-added" : "2020-11-24 14:40:21 +0100", "bdsk-url-1" : "https://doi.org/10.1109/MWSYM.2010.5515248", "issn" : "0149-645X", "date-modified" : "2020-11-24 14:40:29 +0100", "doi" : "10.1109/MWSYM.2010.5515248", "bibtexKey": "Radisic_IMS2010" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2cd0d363b2b1573f7f33014ada6def625/ingmarkallfass", "tags" : [ "20","220","35","50","500","GCPW;GaAs;InAlAs-InGaAs;S-MMIC","GHz","GHz;grounded","HEMT","MMIC","MMIC;cascode","amplifier","amplifiers;submillimetre","arsenide;indium","circuit","circuit;class-B","circuit;frequency","circuits;","circuits;III-V","circuits;waveguide-to-microstrip","communication","compounds;coplanar","compounds;submillimetre","coplanar","doubler","frequency","high-electron","integrated","mobility","module;amplifier","monolithic","multipliers;gallium","mum;submillimeter-wave","nm;size","semiconductors;aluminium","sensors;size","systems;metamorphic","technology;metamorphic","technology;monolithically","to","topology;grounded","transistor","transitions;HEMT","transitions;next-generation","wave","waveguide","waveguide;high-data-rate","waveguides;frequency","wireless" ], "intraHash" : "cd0d363b2b1573f7f33014ada6def625", "interHash" : "de6c65e1d3e9465909d1a2b443d43fc0", "label" : "Metamorphic HEMT MMICs and Modules Operating Between 300 and 500 GHz", "user" : "ingmarkallfass", "description" : "", "date" : "2020-09-07 14:26:58", "changeDate" : "2025-05-26 10:46:15", "count" : 2, "pub-type": "article", "journal": "Solid-State Circuits, IEEE Journal of", "year": "2011", "url": "", "author": [ "A. Tessmann","A. Leuther","V. Hurm","I. Kallfass","H. Massler","M. Kuri","M. Riessle","M. Zink","R. Loesch","M. Seelmann-Eggebert","M. Schlechtweg","O. Ambacher" ], "authors": [ {"first" : "A.", "last" : "Tessmann"}, {"first" : "A.", "last" : "Leuther"}, {"first" : "V.", "last" : "Hurm"}, {"first" : "I.", "last" : "Kallfass"}, {"first" : "H.", "last" : "Massler"}, {"first" : "M.", "last" : "Kuri"}, {"first" : "M.", "last" : "Riessle"}, {"first" : "M.", "last" : "Zink"}, {"first" : "R.", "last" : "Loesch"}, {"first" : "M.", "last" : "Seelmann-Eggebert"}, {"first" : "M.", "last" : "Schlechtweg"}, {"first" : "O.", "last" : "Ambacher"} ], "volume": "46","number": "10","pages": "2193--2202","abstract": "In this paper, we present the development of submillimeter-wave monolithic\nintegrated circuits (S-MMICs) and modules for use in next-generation\nsensors and high-data-rate wireless communication systems, operating\nin the 300-500-GHz frequency regime. A four-stage 460-GHz amplifier\nMMIC and a 440-GHz class-B frequency doubler circuit have been successfully\nrealized using our 35-nm InAlAs/InGaAs-based metamorphic high-electron\nmobility transistor (mHEMT) technology in combination with grounded\ncoplanar circuit topology (GCPW). Additionally, a 500-GHz amplifier\nMMIC was fabricated using a more advanced 20-nm mHEMT technology.\nTo package the submillimeter-wave circuits, a set of waveguide-to-microstrip\ntransitions has been fabricated on both 50- \\#x03BC;m-thick quartz\nand GaAs substrates, covering the frequency range between 220 and\n500 GHz. The E-plane probes were integrated in a four-stage 20-nm\ncascode amplifier circuit to realize a full H -band (220 to 325 GHz)\nS-MMIC amplifier module with monolithically integrated waveguide\ntransitions.", "issn" : "0018-9200", "bdsk-url-1" : "https://doi.org/10.1109/JSSC.2011.2163212", "doi" : "10.1109/JSSC.2011.2163212", "bibtexKey": "Tessmann_JSSC2011" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2d0e8dc8a9dc31a7d2d5b2f304900396a/yvesm", "tags" : [ "Dielectric","Dielectrics","Metals","Microstrip","Slabs","System-on-chip","Waveguide","measurement","transitions" ], "intraHash" : "d0e8dc8a9dc31a7d2d5b2f304900396a", "interHash" : "a4ce9735604977ef1f8788a929098f25", "label" : "Millimeter-Wave Multicast Chip-to-Chip Interconnect Network Using\r\n Dielectric Slab Waveguide", "user" : "yvesm", "description" : "", "date" : "2020-03-19 19:32:56", "changeDate" : "2020-03-19 18:32:56", "count" : 2, "pub-type": "inproceedings", "booktitle": "2018 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM - IMS","series": "IEEE MTT-S International Microwave Symposium","publisher":"IEEE", "year": "2018", "url": "https://ieeexplore.ieee.org/document/8439155", "author": [ "Utpal Dey","Jan Hesselbarth" ], "authors": [ {"first" : "Utpal", "last" : "Dey"}, {"first" : "Jan", "last" : "Hesselbarth"} ], "pages": "378-381","note": "IEEE-MTT-Society International Microwave Symposium (IMS), Philadelphia, PA, JUN 10-15, 2018", "book-group-author" : "IEEE", "isbn" : "978-1-5386-5067-7", "language" : "English", "affiliation" : "Dey, U (Reprint Author), Univ Stuttgart, Inst Radio Frequency Technol, Stuttgart, Germany. Dey, Utpal; Hesselbarth, Jan, Univ Stuttgart, Inst Radio Frequency Technol, Stuttgart, Germany.", "research-areas" : "Engineering", "eissn" : "2576-7216", "issn" : "0149-645X", "orcid-numbers" : "Hesselbarth, Jan/0000-0002-4905-8591", "da" : "2019-03-21", "unique-id" : "ISI:000451173600100", "doi" : "10.1109/MWSYM.2018.8439155", "bibtexKey": "dey2018millimeterwave" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2555749065b3ab126e0e47ffaa3a98bce/yvesm", "tags" : [ "chip-to-chip","dielectric","flexible","interconnect","millimeter","resonator","waveguide","waves" ], "intraHash" : "555749065b3ab126e0e47ffaa3a98bce", "interHash" : "1f238e683dd6c711ec01a5b891e6683a", "label" : "Millimeter-wave Chip-to-Chip Interconnect Using Plastic Wire Operating in Single and Dual Mode", "user" : "yvesm", "description" : "", "date" : "2020-03-19 19:29:54", "changeDate" : "2020-03-19 18:29:54", "count" : 2, "pub-type": "inproceedings", "booktitle": "2018 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM - IMS","series": "IEEE MTT-S International Microwave Symposium","publisher":"IEEE", "year": "2018", "url": "https://ieeexplore.ieee.org/document/8439683", "author": [ "Utpal Dey","Jan Hesselbarth" ], "authors": [ {"first" : "Utpal", "last" : "Dey"}, {"first" : "Jan", "last" : "Hesselbarth"} ], "pages": "1549-1552","note": "IEEE/MTT-S International Microwave Symposium, Philadelphia, PA, JUN 10-15, 2018", "book-group-author" : "IEEE", "isbn" : "978-1-5386-5067-7", "language" : "English", "affiliation" : "Dey, U (Reprint Author), Univ Stuttgart, Inst Radio Frequency Technol, Stuttgart, Germany. Dey, Utpal; Hesselbarth, Jan, Univ Stuttgart, Inst Radio Frequency Technol, Stuttgart, Germany.", "research-areas" : "Engineering", "eissn" : "2576-7216", "issn" : "0149-645X", "orcid-numbers" : "Hesselbarth, Jan/0000-0002-4905-8591", "da" : "2019-03-21", "unique-id" : "ISI:000451173600409", "doi" : "10.1109/MWSYM.2018.8439683", "bibtexKey": "dey2018millimeterwave" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/28dba0bd033612faa8f6af21590911692/yvesm", "tags" : [ "Y-junction","chip-to-chip","dielectric","interconnect","resonator","waveguide" ], "intraHash" : "8dba0bd033612faa8f6af21590911692", "interHash" : "f514c55146b367fdb9fe69cf317db9cd", "label" : "Millimeter-wave dielectric waveguides based chip-to-chip and multicast interconnect", "user" : "yvesm", "description" : "", "date" : "2020-03-19 19:23:40", "changeDate" : "2020-03-19 18:23:40", "count" : 1, "pub-type": "phdthesis", "address":"Stuttgart", "year": "2017", "url": "https://ieeexplore.ieee.org/document/8048234", "author": [ "Utpal Dey","Jan Hesselbarth" ], "authors": [ {"first" : "Utpal", "last" : "Dey"}, {"first" : "Jan", "last" : "Hesselbarth"} ], "supervisorgnd" : "1150815086", "isbn" : "978-1-5090-4036-0", "language" : "eng", "eventdate" : "2019-09-24", "supervisor" : "Hesselbarth, Jan", "doi" : "10.1109/RFIT.2017.8048234", "bibtexKey": "dey2019millimeterwave" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/22715685dba04d0c2f9222c7c77bd1952/ifsw", "tags" : [ "Laser","SolidStateLaser","Waveguide","from:peterberger" ], "intraHash" : "2715685dba04d0c2f9222c7c77bd1952", "interHash" : "11e55bfe25eb7d224307d59f5b49dbd4", "label" : "Applications of Grating Waveguide Structures in Solid-State Lasers", "user" : "ifsw", "description" : "", "date" : "2019-10-09 18:17:21", "changeDate" : "2021-03-18 12:34:15", "count" : 2, "pub-type": "phdthesis", "series": "Laser in der Materialbearbeitung - Forschungsberichte des IFSW","publisher":"utzverlag","address":"München", "year": "2019", "url": "", "author": [ "Martin Rumpel" ], "authors": [ {"first" : "Martin", "last" : "Rumpel"} ], "editor": [ "Thomas Graf" ], "editors": [ {"first" : "Thomas", "last" : "Graf"} ], "pages": "110", "isbn" : "978-3-8316-4801-6", "language" : "en", "bibtexKey": "Rumpel.2019.Applications" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2f2f8a66b7b4d11c1ffd276328e8e63fa/florianfetzer", "tags" : [ "Laser","LaserDevelopment","Marwan,A.","Studienarbeit","Waveguide" ], "intraHash" : "f2f8a66b7b4d11c1ffd276328e8e63fa", "interHash" : "4a919654fc477ad024f0abd98954a193", "label" : "Implementation of the inverse problem for the retrieval of the opto-geometrical parameters of thin-film optical waveguides", "user" : "florianfetzer", "description" : "", "date" : "2019-04-09 09:54:01", "changeDate" : "2019-04-09 07:54:01", "count" : 2, "pub-type": "mastersthesis", "year": "2009", "url": "", "author": [ "Martin Rumpel" ], "authors": [ {"first" : "Martin", "last" : "Rumpel"} ], "number": "IFSW09-29", "bibtexKey": "Rumpel.2009.Implementation" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2f2f8a66b7b4d11c1ffd276328e8e63fa/ifsw", "tags" : [ "Studienarbeit","Laser","from:florianfetzer","Marwan,A.","LaserDevelopment","Waveguide" ], "intraHash" : "f2f8a66b7b4d11c1ffd276328e8e63fa", "interHash" : "4a919654fc477ad024f0abd98954a193", "label" : "Implementation of the inverse problem for the retrieval of the opto-geometrical parameters of thin-film optical waveguides", "user" : "ifsw", "description" : "", "date" : "2019-04-09 09:54:01", "changeDate" : "2019-04-09 07:54:01", "count" : 2, "pub-type": "mastersthesis", "year": "2009", "url": "", "author": [ "Martin Rumpel" ], "authors": [ {"first" : "Martin", "last" : "Rumpel"} ], "number": "IFSW09-29", "bibtexKey": "Rumpel.2009.Implementation" } ] }