Femtosecond laser fabricated multimode fiber sensors interrogated by optical-carrier-based microwave interferometry technique for distributed strain sensing

2016 ◽  
Author(s):  
Liwei Hua ◽  
Yang Song ◽  
Jie Huang ◽  
Baokai Cheng ◽  
Wenge Zhu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Multimode Fiber ◽  
Strain Sensing ◽  
Optical Carrier ◽  
Fiber Sensors ◽  
Microwave Interferometry ◽  
Distributed Strain

scholarly journals Distributed Strain Sensing from Different Optical Fiber Configurations

Inventions ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 67 ◽  
Author(s):  
Daniel Drake ◽  
Rani Sullivan ◽  
J. Wilson
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Strain Sensing ◽  
Fiber Sensors ◽  
Interferometric Technique ◽  
Sensor Configuration ◽  
Strain Gauge Measurements ◽  
Cantilevered Beams ◽  
Distributed Strain ◽  
Good Agreement

Strain distributions were obtained from optical fibers arranged in three different configurations on transversely-loaded cantilevered beams. Traditional strain measurement sensors, such as strain gauges, are limited to measuring strain at discrete points on a structural member. However, distributed optical fibers can measure high spatial (<1 mm spacing) strain or temperature distributions. In this study, optical fibers in spiral, grid, and rosette configurations were bonded to aluminum cantilevered beams subjected to tip loads. Strain distributions from optical fiber sensors were measured using a swept wavelength coherent interferometric technique. The optical fiber strain measurements show good agreement with strain gauge measurements. The attributes of each sensor configuration are discussed.

scholarly journals Temperature and Strain Sensing With Femtosecond Laser Written Bragg Gratings in Defect and Nondefect Suspended-Silica-Core Fibers

2012 ◽  
Vol 24 (7) ◽  
pp. 554-556 ◽  
Author(s):  
Luís André Fernandes ◽  
Martin Becker ◽  
Orlando Frazao ◽  
Kay Schuster ◽  
Jens Kobelke ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Bragg Gratings ◽  
Strain Sensing ◽  
Silica Core

CHARACTERIZING ANOMALIES IN DISTRIBUTED STRAIN MEASUREMENTS OF CAST-IN-SITU BORED PILES

2016 ◽  
Vol 78 (8-5) ◽  
Author(s):  
Hisham Mohamad ◽  
Bun Pin Tee ◽  
Koh An Ang ◽  
Mun Fai Chong
Keyword(s):  
Load Transfer ◽  
Load Test ◽  
Strain Sensing ◽  
Strain Profile ◽  
A New Technique ◽  
Optical Time ◽  
Distributed Optical Fiber ◽  
Non Destructive ◽  
Distributed Strain

This paper describes the method of identifying typical defects of bored cast-in-situ piles when instrumenting using Distributed Optical Fiber Strain Sensing (DOFSS). The DOFSS technology is based on Brillouin Optical Time Domain Analyses (BOTDA), which has the advantage of recording continuous strain profile as opposed to the conventional discrete based sensors such as Vibrating Wire strain gauges. In pile instrumentation particularly, obtaining distributed strain profile is important when analysing the load-transfer and shaft friction of a pile, as well as detecting any anomalies in the strain regime. Features such as defective pile shaft necking, discontinuity of concrete, intrusion of foreign matter and improper toe formation due to contamination of concrete at base with soil particles, among others, may cause the pile to fail. In this study, a new technique of detecting such defects is proposed using DOFSS technology which can potentially supplement the existing non-destructive test (NDT) methods. Discussion on the performance of instrumented piles by means of maintained load test are also presented

Distributed Strain Sensing in der Geotechnik - Teil 2

Bautechnik ◽  
2018 ◽  
Vol 95 (9) ◽  
pp. 653-657
Author(s):  
Arne Kindler ◽  
Stephan Großwig ◽  
Thomas Pfeiffer
Keyword(s):  
Strain Sensing ◽  
Distributed Strain

Fabrication of Optical Fiber Sensors Based on Femtosecond Laser Micro Machining

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Fengfeng Zhou ◽  
Seunghwan Jo ◽  
Xingyu Fu ◽  
Jung-Ting Tsai ◽  
Martin Byung-Guk Jun
Keyword(s):  
Refractive Index ◽  
Femtosecond Laser ◽  
Optical Fiber ◽  
Refractive Index Change ◽  
Optical Fiber Sensors ◽  
Objective Lens ◽  
Machining Parameters ◽  
Fiber Sensors ◽  
The Core ◽  
First Time

Abstract In this research, we proposed fabrication process of optical fiber sensors using femtosecond laser and their applications. A beam of femtosecond laser was focused by an objective lens in the optical fiber. By testing different conditions, a group of machining parameters was found that achieve a minimum machining resolution of 3.2 μm. To ablate the core of the optical fiber, which is buried deep inside the cladding, precisely, part of the cladding was removed to expose the core as close as possible to the air. By making a complex pattern to modify the optical path of the laser inside an optical fiber, a sensitivity of 942.8–1015.6 nm per refractive index unit (nm/RIU) was obtained for liquid refractive index sensing. For another sensor, a sensitivity of 1.38 × 105 nm/RIU was obtained, which is high enough to detect small amount of refractive index change of air. It is known to be the first time that we fabricated a complex microstructure in an optical fiber to modify the propagation of the light using femtosecond laser. This research shows the possibility of a complex modification of light in an optical fiber using laser machining.

Novel Near-Wellbore Fracture Diagnosis for Unconventional Wells Using High-Resolution Distributed Strain Sensing during Production

SPE Journal ◽  
2021 ◽  
pp. 1-10
Author(s):  
Ge Jin ◽  
Gustavo Ugueto ◽  
Magdalena Wojtaszek ◽  
Artur Guzik ◽  
Dana Jurick ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Fiber Optic ◽  
Fracture Network ◽  
Production Performance ◽  
Hydraulic Fractures ◽  
Fracture Aperture ◽  
Strain Sensing ◽  
Extensional Strain ◽  
Cluster Efficiency ◽  
Distributed Strain

Summary The characteristics of hydraulic fractures in the near-wellbore region contain critical information related to the production performance of unconventional wells. We demonstrate a novel application of a fiber-optic-based distributed strain sensing (DSS) technology to measure and characterize near-wellbore fractures and perforation cluster efficiency during production. Distributed fiber-optic-based strain measurements are made based on the frequency shift of the Rayleigh scatter spectrum, which is linearly dependent on strain and temperature changes of the sensing fiber. Strain changes along the wellbore are continuously measured during the shut-in and reopening operations of a well. After removing temperature effects, extensional strain changes can be observed at locations around the perforation cluster during a shut-in period. We interpret that the observed strain changes are caused by near-wellbore fracture aperture changes caused by pressure increases within the near-wellbore fracture network. The depth locations of the measured strain changes correlate well with distributed acoustic sensing (DAS) acoustic intensity measurements that were measured during the stimulation of the well. The shape and magnitude of the strain changes differ significantly between two completion designs in the same well. Different dependencies between strain and borehole pressure can be observed at most of the perforation clusters between the shut-in and reopening periods. We assess that this new type of distributed fiber-optic measurement method can significantly improve understanding of near-wellbore hydraulic fracture characteristics and the relationships between stimulation and production from unconventional oil and gas wells.

scholarly journals Optical Fiber Sensors by Direct Laser Processing: A Review

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6971
Author(s):  
David Pallarés-Aldeiturriaga ◽  
Pablo Roldán-Varona ◽  
Luis Rodríguez-Cobo ◽  
José Miguel López-Higuera
Keyword(s):  
Femtosecond Laser ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Laser Processing ◽  
Optical Fiber Sensors ◽  
Femtosecond Laser Irradiation ◽  
Fiber Sensors ◽  
Continuous Increase ◽  
Rayleigh Backscattering ◽  
Direct Laser

The consolidation of laser micro/nano processing technologies has led to a continuous increase in the complexity of optical fiber sensors. This new avenue offers novel possibilities for advanced sensing in a wide set of application sectors and, especially in the industrial and medical fields. In this review, the most important transducing structures carried out by laser processing in optical fiber are shown. The work covers different types of fiber Bragg gratings with an emphasis in the direct-write technique and their most interesting inscription configurations. Along with gratings, cladding waveguide structures in optical fibers have reached notable importance in the development of new optical fiber transducers. That is why a detailed study is made of the different laser inscription configurations that can be adopted, as well as their current applications. Microcavities manufactured in optical fibers can be used as both optical transducer and hybrid structure to reach advanced soft-matter optical sensing approaches based on optofluidic concepts. These in-fiber cavities manufactured by femtosecond laser irradiation followed by chemical etching are promising tools for biophotonic devices. Finally, the enhanced Rayleigh backscattering fibers by femtosecond laser dots inscription are also discussed, as a consequence of the new sensing possibilities they enable.

Sign in / Sign up

Export Citation Format

Share Document