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- 摘要
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Smart Optical Catheters for Epidurals
摘要： Placing the needle inside the epidural space for locoregional anesthesia is a challenging procedure, which even today is left to the expertise of the operator. Recently, we have demonstrated that the use of optically sensorized needles significantly improves the effectiveness of this procedure. Here, we propose an optimized configuration, where the optical fiber strain sensor is directly integrated inside the epidural catheter. The new design allows the solving of the biocompatibility issues and increases the versatility of the former configuration. Through an in vivo study carried out on a porcine model, we confirm the reliability of our approach, which also opens the way to catheter monitoring during insertion inside biological spaces.
关键词： medical optics instrumentation,fiber optics sensors,clinical applications,fiber Bragg gratings
更新于2025-09-23 15:22:29
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In Vivo Rat Brain Imaging through Full-Field Optical Coherence Microscopy Using an Ultrathin Short Multimode Fiber Probe
摘要： We demonstrate full-field optical coherence microscopy (OCM) using an ultrathin forward-imaging short multimode fiber (SMMF) probe with a core diameter of 50 μm, outer diameter of 125 μm, and length of 7.4 mm, which is a typical graded-index multimode fiber used for optical communications. The axial and lateral resolutions were measured to be 2.14 μm and 2.3 μm, respectively. By inserting the SMMF 4 mm into the cortex of an in vivo rat brain, scanning was performed to a depth of 147 μm from the SMMF facet with a field of view of 47 μm. Three-dimensional (3D) OCM images were obtained at depths ranging from approximately 20 μm to 90 μm. Based on the morphological information of the resliced 3D images and the dependence of the integration of the OCM image signal on the insertion length, the obtained 3D information of nerve fibers has been presented.
关键词： medical optics instrumentation,full-field optical coherence microscopy,endoscopic imaging,fiber optics imaging
更新于2025-09-23 15:22:29
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All-fiberized top-hat beam shaper by mode content control and multimode interference suppression
摘要： A new method of all-fiberized top-hat beam shaper based on controlling mode content and suppressing multimode interference is proposed both numerically and experimentally. The sample is fabricated by fusion splicing a predetermined tapered multimode fiber to a nearly single mode fiber. A 2D simulation model to calculate the mode content weight with different taper ratio and taper shape is established, and the output intensity profile in multimode fiber is investigated. Based on the simulation results, we fabricated an all-fiberized beam shaper, achieving a top-hat beam at a taper ratio of 0.51 with parabolic taper shape. The flatness factor of the top-hat beam is measured to be about 0.6. Theoretical results show a good agreement with the experiment results.
关键词： optical fiber devices,beam shaper,Fiber optics,laser beams
更新于2025-09-23 15:22:29
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Dual Parallel Multi-electrode Traveling Wave Mach-Zehnder Modulator for 200 Gb/s Intra-datacenter Optical Interconnects
摘要： We present a silicon photonic dual parallel multi-electrode Mach-Zehnder modulator (MEMZM) based transmitter targeting 200 Gb/s 4-level pulse amplitude modulation (PAM4) short reach transceivers. The MEMZMs have an average Vπ and electro-optic (EO) bandwidth of 5 V and 38 GHz, respectively. The transmitter is characterized versus receiver equalizer taps, received signal power, driving voltage swing, crosstalk voltage swing, bitrate, and reach. Results reveal that using only a 3-tap equalizer at the receiver, 100 Gb/s PAM4 net rate per lane can be achieved at a bit error rate (BER) below the KP4 forward error correction (KP4-FEC) threshold of 2.4 × 10?4. Moreover, up to 128 Gb/s can be received at a BER below the KP4-FEC threshold using only 2 Vpp and 1 Vpp driving the MEMZM segments. Then, both MEMZMs are driven simultaneously to assess the crosstalk impact on the BER performance at parallel operation. Driven by four binary signals, we demonstrate 200 Gb/s PAM4 transmission over up to 10 km of single mode fiber at a BER below the KP4-FEC threshold.
关键词： Optical interconnects,Fiber optics systems,silicon nanophotonics,Electro-optical systems
更新于2025-09-23 15:22:29
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[IEEE 2018 International Carnahan Conference on Security Technology (ICCST) - Montreal, QC, Canada (2018.10.22-2018.10.25)] 2018 International Carnahan Conference on Security Technology (ICCST) - Reliable Leak Detection in Pipelines Using Integrated DdTS Temperature and DAS Acoustic Fiber-Optic Sensor
摘要： Reliable and early detection of leaks in pipelines transporting liquid or gas is highly desirable. In this work, two orthogonal technologies based on high-sensitivity fiber-optic distributed sensing were integrated into one system and tested for their effectiveness in actual field installations. The first technology is based on temperature difference detection using Distributed Differential Temperature Sensor (DdTS or DDTS). The second is based on Distributed Acoustic Sensor (DAS), which uses Coherent Optical Time-Domain Reflectometry (C-OTDR). DdTS can almost instantaneously detect a temperature difference in the optical fiber as low as 0.0005 οC, while C-OTDR can detect minute wide-bandwidth acoustic signals. Both technologies can detect the location of a leak to within a few meters. Experimental results for water and nitrogen gas leaks detected by the integrated system are presented for two different installations in the field – one where the cable was buried directly in the soil and another where the cable was buried in soil inside a 2” conduit for about 29 km. DdTS reliably detected leaks at both installations, while DAS detected leaks only when the cable was buried directly in soil. Test results show that the integration of both DdTS and DAS technologies can increase the probability of leak detection and minimize false/nuisance alarms. The integrated system also detected third party interference (TPI), thus providing a one-system solution for pipeline integrity monitoring and intrusion detection up to 40 km from a central location.
关键词： Oil and Gas Pipeline,DdTS,Leak Detection,Fiber Optics Sensor,DTS,TPI,DAS,C-OTDR
更新于2025-09-23 15:22:29
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Transforming the Fiber-Optic Network into a Dense and Ultrasensitive Seismic Sensor Array
摘要： We show a technology capable of performing position-resolved measurement of nanostrain perturbations along a conventional optical fiber cable, with meter-scale resolution. This technology can be deployed in already existing networks to achieve a dense and ultrasensitive seismic sensor array. Applications ranging from seismic protection to chemical sensing are explored.
关键词： seismology,distributed fiber optics sensors,Rayleigh scattering,optical time domain reflectometry,distributed acoustic sensors
更新于2025-09-23 15:22:29
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Field Water Balance Closure with Actively Heated Fiber-Optics and Point-Based Soil Water Sensors
摘要： While traditional soil water sensors measure soil water content (SWC) at point scale, the actively heated fiber-optics (AHFO) sensor measures the SWC at field scale. This study compared the performance of a distributed (e.g., AHFO) and a point-based sensor on closing the field water balance and estimating the evapotranspiration (ET). Both sensors failed to close the water balance and produced larger errors in estimated ET (ETε), particularly for longer time periods with >60 mm change in soil water storage (?SWS), and this was attributed to a lack of SWC measurements from deeper layers (>0.24 m). Performance of the two sensors was different when only the periods of <60 mm ?SWS were considered; significantly lower residual of the water balance (Re) and ETε of the distributed sensor showed that it could capture the small-scale spatial variability of SWC that the point-based sensor missed during wet (70–104 mm SWS) periods of <60 mm ?SWS. Overall, this study showed the potential of the distributed sensor to provide a more accurate value of SWS at field scale and to reduce the errors in water balance for shorter wet periods. It is suggested to include SWC measurements from deeper layers to better evaluate the performance of the distributed sensor, especially for longer time periods of >60 mm ?SWS, in future studies.
关键词： soil water storage,actively heated fiber-optics,soil water balance
更新于2025-09-23 15:22:29
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Recent progress in all-fiber non-Gaussian optical beam shaping technologies
摘要： Rapid development of fiber lasers are being followed by wide ranges of applications in laser processing technologies. One of the key parameters to determine the laser-matter interaction is beam shape and there have been intense research activities on beam shaping using bulk-optics. However, fiber optic solutions would take clear advantages over bulk-optics especially for fiber laser sources in terms of the beam conversion efficiency, the throughput power, and the compact footprint. In this article, all-fiber optical beam shaping technologies are reviewed and they are categorized as the phase front modification on the fiber facet, the surface plasmonics on fiber, all-fiber Fourier transformation, and multimode interference. Their physical principles, beam shaping capability, and some of the novel applications are explained
关键词： Phase front engineering,Laser beam,Surface plasmon polariton,Beam Shaping,Multimode Interference,Fourier Transform,Fiber Optics,Single mode optical fiber
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [AIP Publishing LLC PROGRESS IN APPLIED MATHEMATICS IN SCIENCE AND ENGINEERING PROCEEDINGS - Bali, Indonesia (29 September–1 October 2015)] - Reflectance imaging by fiber bundle endoscope: Vertical reconstruction by multipositional illumination
摘要： Fiber bundles for imaging internal organs with minimum physical damage have been increasingly developed for both basic life sciences and clinical applications. Reflectance imaging is possible using fiber bundles for detecting the intrinsic optical contrast of blood vessels and tissue structure. The placement of an illumination source adjacent to imaging optics causes scattered light from deeper tissue layers to illuminate superficial tissues and results in a reflectance image. However, it does not have focal capacity and lacks depth resolution. In this study, we performed spatial analysis for the vertical reconstruction of in vivo tissues using a multipositional illumination scheme. The observed image corresponded to the “shadow” of a target object. When we manipulated the location of illumination, the shadow moved horizontally depending on the depth of the target. We used this horizontal displacement as a cue and successfully performed the vertical reconstruction of mouse brain blood vessels.
关键词： Fiber optics,Reflectance imaging,Endoscopy
更新于2025-09-23 15:21:21
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[OSA Optical Fiber Sensors - Lausanne (2018..-..)] 26th International Conference on Optical Fiber Sensors - Thermal and Residual Strain Response of an FBG-Based Temperature Sensor Embedded in Carbon Fiber Reinforced Composites
摘要： A strain-free temperature sensor based on a fiber Bragg grating loosely embedded in carbon fiber reinforced polymers is investigated. The effects of different anti-stick materials for packaging on the temperature and residual-strain responses are evaluated.
关键词： Fiber optics sensors,Fiber Bragg gratings
更新于2025-09-23 15:21:01