Search query: hollow core optical fiber

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abstract: Laser spectroscopy outperforms electrochemical and semiconductor gas sensors in selectivity and environmental survivability. However, the performance of the state of the art laser sensors is still insufficient for many high precision applications. Here, we report mode phase difference photothermal spectroscopy with a dual mode anti resonant hollow core optical fiber and demonstrate all fiber gas (acetylene) detection down to ppt (parts per trillion) and <1% instability over a period of 3 hours. An anti resonant hollow core fiber could be designed to transmit light signals over a broad wavelength range from visible to infrared, covering molecular absorption lines of many important gases. This would enable multi component gas detection with a single sensing element and pave the way for ultra precision gas sensing for medical, environmental and industrial applications. Typically, the performance of the state of the art laser sensors is insufficient for many high precision applications. Here, the authors report mode phase difference photothermal spectroscopy with a dual mode anti resonant hollow core optical fiber and demonstrate acetylene detection with ultra high sensitivity.
author_names: Pengcheng Zhao

Yan Zhao

Haihong Bao

Hoi Lut Ho

Wei Jin

Shangchun Fan

Shoufei Gao

Yingying Wang

Pu Wang
title: Mode phase difference photothermal spectroscopy for gas detection with an anti resonant hollow core optical fiber
venue: Nature Communications
year: 2020

abstract: Laser based gas sensors utilizing various light gas interaction phenomena have proved their capacity for detecting different gases. However, achieving reasonable sensitivity, especially in the mid infrared, is crucial. Improving sensor detectivity usually requires incorporating multipass cells, which increase the light gas interaction path length at a cost of reduced stability. An unconventional solution comes with the aid of hollow core fibers. In such a fiber, light is guided inside an air core which, when filled with the analyte gas can serve as a low volume and robust absorption cell. Here we report on the use of a borosilicate antiresonant hollow core fiber for laser based gas sensing. Due to its unique structure and guidance, this fiber provides low loss, single mode transmission \gt} {5}\unicode{x00B5}\rm m}>5um. The feasibility of using the fiber as a gas cell was verified by detecting nitrous oxide at 5.26 um with a minimum detection limit of 20 ppbv.
author_names: Piotr Jaworski

Karol Krzempek

Grzegorz Dudzik

Pier J A Sazio

Walter Belardi
title: Nitrous oxide detection at 5.26 um with a compound glass antiresonant hollow core optical fiber.
venue: Optics letters
year: 2020

abstract: We made and characterized two Fabry Perot interferometer samples made of the latest generation hollow core fiber with sub 1 dB/km loss. Thanks to this low transmission loss, we achieved a finesse of over 140 and 120, for interferometer lengths of 5 and 23 m, respectively. This resulted in transmission peaks as narrow as 47 kHz. Our all fiber Fabry Perot interferometers have standard single mode fiber pigtails (for easy integration in conventional fiber optic systems) and employ fiber mode field adapters to enable low loss coupling between the pigtails and the low loss hollow core fiber. The high reflectivity mirrors >98% were deposited directly on the fiber mode field adapters, which were glued to the hollow core fiber, resulting in permanently aligned Fabry Perot interferometers. We also measured how the position of the transmission peaks change with temperature (an important performance metrics for most applications, e.g. when used as a narrow band band pass filter) and found that it changed 14.5 times less in our Fabry Perot interferometer relative to a similar device made of standard single mode fiber.
author_names: Meng Ding

Matej Komanec

Dmytro Suslov

Daniel Dousek

Stanislav Zvanovec

Eric R Numkam Fokoua

Thomas D Bradley

Francesco Poletti

David John Richardson

Radan Slavik
title: Long Length and Thermally Stable High Finesse Fabry Perot Interferometers Made of Hollow Core Optical Fiber
venue: Journal of Lightwave Technology
year: 2020

abstract: An ultrahigh resolution thickness measurement sensor was proposed based on a single mode hollow core single mode (SMF HCF SMF) fiber structure by coating a thin layer of material on the HCF surface. Theoretical analysis shows that the SMF HCF SMF fiber structure can measure coating thickness down to sub nanometers. An experimental study was carried out by coating a thin layer of graphene oxide (GO) on the HCF surface of the fabricated SMF HCF SMF fiber structure. The experimental results show that the fiber sensor structure can detect a thin layer with a thickness down to 0.21 nanometers, which agrees well with the simulation results. The proposed sensing technology has the advantages of simple configuration, ease of fabrication, low cost, high resolution, and good repeatability, which offer great potential for practical thickness measurement applications.
author_names: Zheyu Wu

Bin Liu

Jiangfeng Zhu

Juan Liu

Shengpeng Wan

Tao Wu

Jinghua Sun
title: Ultrahigh Resolution Thickness Measurement Technique Based on a Hollow Core Optical Fiber Structure
venue: Sensors
year: 2020

abstract: We experimentally demonstrate for the first time a successful fabrication of a tellurite hollow core optical fiber which has a mid infrared transmission range. The wall thickness of each cladding air hole is about 2.8 um and the outer diameter of the full air hole structure D is approximately 110 um. The results show that the measured transmission spectrum can expand up to 3.9 um. In addition, it is expected that the transmission can extend to around 6 um. When the input light is linearly polarized, it can be maintained after propagating through a 17 cm long fiber.
author_names: Hoang Tuan Tong

Nobuhiko Nishiharaguchi

Takenobu Suzuki

Yasutake Ohishi
title: Mid infrared transmission by a tellurite hollow core optical fiber.
venue: Optics express
year: 2019

abstract: The background, optical properties, and applications of low loss negative curvature hollow core fiber are reviewed. Data on spectral attenuation are collated and extended.
author_names: Fei Yu

Jonathan C Knight
title: Negative Curvature Hollow Core Optical Fiber
venue: IEEE Journal of Selected Topics in Quantum Electronics
year: 2016

abstract: In this paper, a novel topology for refractive index optical fiber sensors based on surface plasmon resonance (SPR) phenomenon is presented. The fiber core has a graded refractive index and there is a hole at the center of the core which is coated by silver. The analyte is injected into the hole. In our structure, there is no need for removing the cladding of the fiber. Two types of graded refractive index profiles are investigated in this paper. The proposed sensor is simulated using finite difference time domain method. The results show that the presented SPR sensor has a good spectral response and suitable sensory specifications. The sensitivity of the proposed sensor is about 4350 nm/RIU. The figure of merit of this sensor is 149 RIU 1 The proposed sensor can be used for measuring refractive indices between 1.38 and 1.49. As a result, it can be used for bio sensing applications. One of the advantages of the proposed sensor is that it is label free.
author_names: Ruhallah Nasirifar

Mohammad Danaie

Abbas Dideban
title: Hollow core graded index optical fiber refractive index sensor based on surface plasmon resonance
year: 2020

abstract: Abstract An optical fiber strain sensor based on a Mach Zehnder interferometer (MZI) is demonstrated experimentally. The sensor is fabricated by fusion splicing a tapered hollow core fiber (THCF) with a 500 um taper region between two single mode fibers (SMFs) Tapering on the HCF increases the sensor's strain sensitivity to 2.7 pm/ue in a measurement range of 0 ue to 2100 ue, 1.5 times larger than that of all fiber MZI strain sensors without tapered areas (approximately 1.8 pm/ue) The experimental results show that the sensor has good stability and repeatability. This sensor has high strain sensitivity and low temperature sensitivity and can be used in environments with little temperature fluctuation.
author_names: Leigang Dong

Tingting Gang

Ce Bian

Rongxin Tong

Jie Wang

Manli Hu
title: A high sensitivity optical fiber strain sensor based on hollow core tapering
year: 2020

author_names: Hoang Tuan Tong

Nobuhiko Nishiharaguchi

Takenobu Suzuki

Yasutake Ohishi
title: Fabrication of a novel tellurite hollow core optical fiber
venue: Journal of the Ceramic Society of Japan
year: 2019

abstract: We investigate the impact of input pulse duration and peak power of a femtosecond laser on pulse broadening and propagation losses in selected hollow core antiresonant fiber (HC ARF) The mixed effects of strong self phase modulation and relatively weak Raman scattering broaden the spectral width, which in turn causes a portion of the output spectrum to exceed the transmission band of the fiber, resulting in transmission losses. By designing and setting up a gas flow control system and a vacuum system, the nonlinear behavior of the fiber filled with different pressurized gases is investigated. The experimental results show that replacing the air molecules in the fiber core with argon can weaken pulse broadening and increase the transmittable peak power by 14 MW for a given 122 MW input, while a vacuum system can reduce the nonlinearity to a larger extent, therefore enhancing the transmission of HC ARF by at least 26 MW.
author_names: Shouyue Wu

Bartlomiej Siwicki

Richard M Carter

Fabio Biancalana

Jonathan D Shephard

Duncan P Hand
title: Impact of nonlinear effects on transmission losses of hollow core antiresonant negative curvature optical fiber.
venue: Applied optics
year: 2020