Kilometer length low loss enhanced back scattering fiber for distributed sensing

Westbrook, Paul S.; Feder, K.; Ortiz, R.; Kremp, Tristan; Monberg, Eric M.; Wu, Hongchao; Simoff, Debra A.; Shenk, Scott

doi:10.1117/12.2276357

Cited by 14 publications

(16 citation statements)

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“…When fiber with low Rayleigh backscattering is used as the distributed feedback for a random fiber laser application, a long piece of fiber is required resulting in a high lasing threshold and poor stability. In recent years, UV lasers have been used to increase light backscattering in optical fibers for distributed temperature and strain measurements with higher spatial resolution and higher signal-to-noise ratio (SNR) [ 44 , 57 ]. However, H 2 -loading of SMF-28 and specialty fibers with high Ge-concentrations are usually required to increase the fiber’s UV photosensitivity.…”

Section: Femtosecond Laser-enhanced Fiber Scattering: Random Fibermentioning

confidence: 99%

Ultrafast Laser Processing of Optical Fibers for Sensing Applications

Mihailov

Hnatovsky

Abdukerim

et al. 2021

Sensors

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A review of recent progress in the use of infrared femtosecond lasers to fabricate optical fiber sensors that incorporate fiber Bragg gratings (FBG) and random fiber gratings (RFG) is presented. The important advancements in femtosecond laser writing based on the phase mask technique now allow through-the-coating (TTC) fabrication of Bragg gratings in ultra-thin fiber filaments, tilted fiber Bragg gratings, and 1000 °C-resistant fiber Bragg gratings with very strong cladding modes. As an example, through-the-coating femtosecond laser writing is used to manufacture distributed fiber Bragg grating sensor arrays for oil pipeline leak detection. The plane-by-plane femtosecond laser writing technique used for the inscription of random fiber gratings is also reviewed and novel applications of the resultant devices in distributed temperature sensing, fiber lasers and fiber laser sensors are discussed.

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Section: Femtosecond Laser-enhanced Fiber Scattering: Random Fibermentioning

confidence: 99%

Ultrafast Laser Processing of Optical Fibers for Sensing Applications

Mihailov

Hnatovsky

Abdukerim

et al. 2021

Sensors

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“…At large distances sensitivity may be raised by increasing backscatter intensity. Currently, many works focus on enhancing the backscatter by use of continuous gratings [38,39,40]. Also experiments with range-optimized fiber configurations combining low-loss fiber with high scattering fiber have recently been published [69].…”

Section: Dvs Performance Benefits Of Using Scattering Dots Ffbermentioning

confidence: 99%

“…Many of the above-listed methods involve quite complex photonics on the sensing interrogator side, often with high demands on components like laser source, pulse shaper or detection path. In recent years, many investigations have been performed on the topic of how to improve C-OTDR DAS sensory performance from the side of the sensing fiber, proposing the use of modified optical fiber structured with large ultra-weak FBG arrays or continuous gratings [27,28,29,30,31,32,33,34,35,36,37,38,39,40]. Developments towards the demodulation of phase variations using discrete reflectors in optical fiber have, however, had a long history already.…”

Section: Introductionmentioning

confidence: 99%

“…This method to improve phase-sensitive OTDR with a FBG-interferometric sensing scheme was first proposed by Zhu et al [28]. The different proposed FBG array-enhanced DAS/DVS methods complement and work in conjunction with various phase demodulation approaches to C-OTDR (Φ-OTDR) in order to raise sensitivity, increase measurement precision or to attain greater sensing ranges by enhancing the backscatter [38,39,40].…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Distributed Fiber Optic Vibration Sensing and Simultaneous Temperature Gradient Sensing Using Traditional C-OTDR and Structured Fiber with Scattering Dots

Hicke

Eisermann

Chruscicki

2019

Sensors

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We present results demonstrating several beneficial effects on distributed fiber optic vibration sensing (DVS) functionality and performance resulting from utilizing standard single mode optical fiber (SMF) with femtosecond laser-inscribed equally-spaced simple scattering dots. This modification is particularly useful when using traditional single-wavelength amplitude-based coherent optical time domain reflectometry (C-OTDR) as sensing method. Local sensitivity is increased in quasi-distributed interferometric sensing zones which are formed by the fiber segments between subsequent pairs of the scattering dots. The otherwise nonlinear transfer function is overwritten with that of an ordinary two-beam interferometer. This linearizes the phase response to monotonous temperature variations. Furthermore, sensitivity fading is mitigated and the demodulation of low-frequency signals is enabled. The modification also allows for the quantitative determination of local temperature gradients directly from the C-OTDR intensity traces. The dots’ reflectivities and thus the induced attenuation can be tuned via the inscription process parameters. Our approach is a simple, robust and cost-effective way to gain these sensing improvements without the need for more sophisticated interrogator technology or more complex fiber structuring, e.g., based on ultra-weak FBG arrays. Our claims are substantiated by experimental evidence.

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“…Although several researchers have experimentally tracked the amplification of Rayleigh scattering feedback in an optical fiber to improve the random fiber laser efficiency [9,10], there hasn't been a thorough study of the effect of Rayleigh scattering enhancement on the random fiber laser efficiency. Recently, Kashyap et al reported that the Rayleigh scattering can be enhanced by several orders of magnitude by simple UV irradiation of the optical fiber, while little fiber loss is introduced [11,12], so it is of great interest to investigate the Rayleigh scattering and loss enhancement effect on the random fiber laser efficiency, for the optimization design of the random fiber laser by the Rayleigh scattering and loss manipulation in the optical fiber.…”

Section: Introductionmentioning

confidence: 99%