TY - CONF A1 - Shaheen, Sabahat A1 - Hicke, Konstantin T1 - Measurement of Geometric Phase using a φ-OTDR setup T2 - 27th conference on Optical Fiber Sensors N2 - Geometric phase showing sensitivity to changes in polarisation state and intensity of backscattered light is measured using a novel φ-OTDR setup based on coherent heterodyne detection. Principle is demonstrated using a polarisation scrambler inline a fiber-under-test. T2 - Optical Fiber Sensors 2022 CY - Alexandria, Virginia, United States DA - 29.08.2022 KW - Coherent Heterodyne KW - Geometric Phase KW - Distributed Fiber Optic Sensor PY - 2022 SN - 978-1-957171-14-2 SP - W4.72 AN - OPUS4-56116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat T1 - Photonic crystal fibers for microwave signal processing T2 - True-Time Delay Line Based on Dispersion-Flattened 19-Core Photonic Crystal Fiber N2 - We present a novel design of an optical True Time Delay Line based on a 19-core Photonic Crystal Fiber that operates in a broad radiofrequency signal processing range from 1 to 67 GHz on a 10-km link, thus enabling simultaneous signal distribution and processing. T2 - 2021 IEEE Photonics Conference (IPC) CY - Vancouver, BC, Canada DA - 18.10.2021 KW - Delay lines KW - Photonic crytal fibers KW - Optical fibers PY - 2021 SN - 978-1-6654-1601-6 DO - https://doi.org/10.1109/IPC48725.2021.9592934 SP - 1 EP - 3 PB - IEEE AN - OPUS4-56582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shaheen, Sabahat A1 - Hicke, Konstantin T1 - Geometric phase in distributed fiber optic sensing JF - Optics Letters N2 - The geometric phase in the beat signal from coherent interference of two frequency-offset light beams is measured using a novel distributed optical fiber sensing setup. In a fiber optic medium, with changing beam intensities, to the best of our knowledge, ours is the first measurement of the mentioned geometric phase. Experimental results of applying a 100-Hz sinusoidal stimulus to a polarization scrambler and a piezoelectric transducer inline to an optical fiber are presented. The results may enable novel distributed fiber sensing techniques. KW - Distributed fiber optic sensing KW - Geometric phase measurement KW - Distributed vibration sensing KW - C-OTDR PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556053 DO - https://doi.org/10.1364/OL.464259 VL - 47 IS - 15 SP - 3932 EP - 3935 PB - Optica CY - Washington D.C., USA AN - OPUS4-55605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat T1 - Coherent heterodyne OTDR based on geometric phase N2 - Results showing a Distributed Acoustic Sensing setup based on Geometric Phase as opposed to the traditionally measured Dynamic Phase. T2 - Meeting on PhD progress CY - Online Meeting DA - 09.08.2022 KW - Coherent Heterodyne KW - Distributed Acoustic Sensing KW - Geometric Phase PY - 2022 AN - OPUS4-55717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat T1 - Earthquake Monitoring N2 - A brief introduction of my previous research experince involving design of Photonic Crystal Fiber followed by introduction to my current PhD project at BAM involving earthquake monitoring. First results of my original setup for measuring geometric Phase are included. T2 - Intro to PhD project on Earthquake Monitoring CY - Berlin, Germany DA - 01.04.2022 KW - Earthquake Monitoring KW - Geometric Phase PY - 2022 AN - OPUS4-55707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat T1 - Geometric phase in distributed fiber sensing N2 - Introduction to Geometric Phase in time and space domain. Results showing successful detection of Geometric Phase using a distributed fiber optic sensor setup are presented. T2 - Detecting Geometric Phase CY - Online Meeting DA - 10.05.2022 KW - Coherent Heterodyne KW - Geometric Phase KW - Distributed Fiber Optic Sensor PY - 2022 AN - OPUS4-55708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat A1 - Konstantin, Hicke T1 - Measurement of Geometric Phase using a φ-OTDR setup N2 - Geometric phase showing sensitivity to changes in polarisation state (SOP) and intensity of backscattered light is measured using a novel φ-OTDR setup based on coherent heterodyne detection. Principle is demonstrated using a polarisation scrambler inline a fiber-under-test. T2 - 27th Optical Fiber Sensors conference CY - Alexandria, United States DA - 29.08.2022 KW - Coherent Heterodyne KW - Geometric Phase KW - Distributed Fiber Optic Sensor PY - 2022 AN - OPUS4-55710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat T1 - Distributed fiber optic sensing for earthquake monitoring N2 - Earthquake monitoring using geometric phase. Planned foeld measurements at Horstwalde (BAM TTS) are discussed with Professor Serge Shapiro of Free University for a possible collaboration. T2 - Invitation for coolaboration on Earthquake Monitoring project CY - Online Meeting DA - 15.09.22 KW - Coherent Heterodyne KW - Geometric Phase KW - Distributed Fiber Optic Sensor PY - 2022 AN - OPUS4-55767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat T1 - Earth's near surface characterisation using phi-OTDR based on Geometric Phase N2 - A novel DAS setup based on geometric phase is used to measure surface waves of the Earth. They carry useful information about the structure and material of the Earth. T2 - Optica Sensing Congress CY - Munich, Germany DA - 30.07.2023 KW - Geometric Phase KW - Distributed Fiber Optic Sensor KW - Surface waves KW - Coherent Heterodyne KW - Geophysics PY - 2023 AN - OPUS4-58043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Earth’s near-surface characterisation using phi-OTDR based on geometric phase N2 - Phase-sensitive OTDR based on geometric phase for the first time detects surface waves generated by quarry blasts of 25 kg explosives. Inversion of dispersion curves provides depth profiles of shear-wave velocities of surface waves. T2 - Optica Sensing Congress CY - Munich, Germany DA - 30.07.2023 KW - Geophysics KW - Geometric Phase KW - Distributed Fiber Optic Sensor KW - Coherent Heterodyne KW - Surface waves PY - 2023 SP - 1 EP - 2 AN - OPUS4-58044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shaheen, Sabahat A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Phase-sensitive optical time domain reflectometry based on geometric phase measurement JF - Scientific Reports N2 - A phase-sensitive optical time domain reflectometer based on coherent heterodyne detection of geometric phase in the beat signal of light, is reported for the first time to our knowledge. The use of the geometric phase to extract strain makes it immune to polarisation diversity fading. This is because a polarisation mismatch between the interfering beams is not a hindrance to its measurement. The geometric phase is calculated using the amplitude of the beat signal and individual beam intensities without any need for phase unwrapping. It is measured per beat period and can be equated with the traditionally measured dynamic phase with appropriate scaling. The results show that the system based on the geometric phase successfully measures strain, free from polarisation mismatch fading and phase unwrapping errors, providing a completely novel solution to these problems. KW - Fiber optic sensing KW - Distributed acoustic sensing KW - DAS KW - Geometric phase KW - Pancharatnam–Berry phase KW - Berry phase PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570307 DO - https://doi.org/10.1038/s41598-023-29972-4 VL - 13 SP - 1 EP - 11 PB - Nature Portfolio CY - London AN - OPUS4-57030 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - phi-g OTDR utilizing geometric phase T2 - Phase-sensitive optical time domain reflectometry based on geometric phase measurement N2 - Geometric phase measured per beat period in a ϕ-OTDR based on coherent heterodyne detection is used to measure strain. Proposed method is robust to polarisation mismatch fading as a polarisation mismatch between interfering beams is not a hindrance to the measurement of the geometric phase. The Geometric phase is a function of the intensities of the interfering beams as well as the envelope of the beat signal. Its calculation does not require phase unwrapping and accordingly does not suffer the phase unwrapping errors. It is required to be equated with the traditionally measured phase by applying a scaling factor. The spatial resolution of the measured strain is reduced as it is calculated per beat period. Results are verified using a piezo-electric transducer inline a fiber-under-test. T2 - European Workshop on Optical Fibre Sensors (EWOFS 2023) CY - Mons, Belgium DA - 23.05.23 KW - Coherent Heterodyne KW - Geometric Phase KW - Distributed Fiber Optic Sensor PY - 2023 DO - https://doi.org/10.1117/12.2678295 SP - 1 EP - 5 PB - SPIE AN - OPUS4-57551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Earth‘s near surface characterisation using DAS based on geometric phase N2 - Results obtained from field measurements using a novel distributed acoustic sensor based on geometric phase. The target application is Seismology where we attempt to characterise the Earth's subsurface. T2 - Colaboration on Earthquake Monitoring project with Freue University CY - Berlin, Germany DA - 18.09.2023 KW - Geometric Phase KW - Distributed Fiber Optic Sensor KW - Seismology KW - Coherent Heterodyne KW - Subsurface KW - Earth KW - Surface waves KW - Geophysics PY - 2023 AN - OPUS4-58460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shaheen, Sabahat A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Blast-Assisted Subsurface Characterisation Using a Novel Distributed Acoustic Sensing Setup Based on Geometric Phases JF - Sensors N2 - A novel DAS setup based on geometric phases in coherent heterodyne detection is applied for the first time to the characterisation of the Earth’s subsurface. In addition, an optimisation of the proposed setup in terms of its spatial resolution is also presented for the first time. The surface waves are generated by strong blasts of 25 kg of explosives at a dedicated test site. A 10 km dark fiber link in the vicinity of the test site connected to the test setup records the resulting strain signals. The spike-free and low-noise strain data thus obtained minimize post-processing requirements, making the setup a candidate for real-time seismic monitoring. An analysis of the dispersion characteristics of the generated surface waves is performed using a recently reported optimised seismic interferometric technique. Based on the dispersion characteristics, the shear wave velocities of the surface waves as a function of the depth profile of the Earth’s crust are determined using an optimised evolutionary algorithm. KW - Geophysics KW - Geometric Phase KW - Distributed Fiber Optic Sensor KW - Distributed Acoustic Sensing KW - Earthquake Monitoring KW - Seismology PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591913 DO - https://doi.org/10.3390/s24010030 VL - 24 IS - 1 SP - 1 EP - 12 PB - MDPI AN - OPUS4-59191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shaheen, Sabahat A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - ɸgOTDR utilizing Geometric Phase for Earthquake Monitoring N2 - Geometric phase measured per beat period1 in a ɸ-OTDR based on coherent heterodyne detection2 is used to measure strain3, instead of the traditionally measured dynamic phase. The new setup is referred to as a ɸgOTDR. Results are verified using a piezo-electric transducer inline a fiber-undertest. T2 - European Workshop on Optical Fibre Sensors (EWOFS 2023) CY - Mons, Belgium DA - 23.05.2023 KW - Geometric Phase KW - Distributed Fiber Optic Sensor KW - Coherent Heterodyne PY - 2023 AN - OPUS4-57607 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -