SE1350785A1 - Optical waveguide gas sensor - Google Patents

Optical waveguide gas sensor

Info

Publication number
SE1350785A1
SE1350785A1 SE1350785A SE1350785A SE1350785A1 SE 1350785 A1 SE1350785 A1 SE 1350785A1 SE 1350785 A SE1350785 A SE 1350785A SE 1350785 A SE1350785 A SE 1350785A SE 1350785 A1 SE1350785 A1 SE 1350785A1
Authority
SE
Sweden
Prior art keywords
optical waveguide
tubular element
outer tubular
light guiding
light
Prior art date
Application number
SE1350785A
Other languages
English (en)
Other versions
SE1350785A2 (en
Inventor
Walter Margulis
Original Assignee
Acreo Swedish Ict Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Acreo Swedish Ict Ab filed Critical Acreo Swedish Ict Ab
Priority to SE1350785A priority Critical patent/SE1350785A2/en
Publication of SE1350785A1 publication Critical patent/SE1350785A1/sv
Publication of SE1350785A2 publication Critical patent/SE1350785A2/en

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01Arrangements or apparatus for facilitating the optical investigation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01Manufacture of glass fibres or filaments
    • C03B37/012Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01211Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/65Raman scattering
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02Optical fibres with cladding with or without a coating
    • G02B6/032Optical fibres with cladding with or without a coating with non solid core or cladding

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Description

15 20 25 30 Optical fibers having a hollow core are known in the art. Such hollow cores typically guides light by way of a photonic bandgap structure (PBG) arranged within the fiber.
One example of an optical waveguide environmental sensor can be found in US 7,343,074 which disclose a waveguide in the form of an optical fiber, where the cladding contains a photonic bandgap structure having a lattice-type microstructure enveloping a light conducting hollow core portion.
The cladding further includes at least one elongated side opening so that the hollow core portion is exposed to the ambient environment.
However, in order to form the elongated opening, the cladding must be chemically etched or laser machined. Such a process is both complicated and time consuming, thereby increasing the cost of manufacturing the sensor. The process of forming the opening may furthermore damage or disrupt the photonic bandgap structure in an uncontrolled manner such that the performance of the light guide is degraded.
Summarv of the lnvention ln view of the above-mentioned and other drawbacks of the prior art, a general object of the present invention is to provide an improved device for use as an optical waveguide environmental sensor.
According to a first aspect of the present invention, it is therefore provided an open hollow core optical waveguide for a gas sensor comprising: an outer tubular element having a sidewall, comprising an elongated opening in said sidewall extending in the longitudinal direction along the length of a portion of said tubular element; a transparent inner hollow light guiding structure forming a light guiding core, attached to an inner wall of the outer tubular element, the inner hollow light guiding structure comprising an elongated opening, arranged such that the light guiding core is in fluid communication with the elongated opening of the outer tubular element.
The hollow core optical waveguide can be understood as an optical fiber having a hollow core, and an additional structure within the hollow core 10 15 20 25 30 forming a confinement region for light propagating in the core. Through the openings in the inner element and the outer element, the environment outside of the optical waveguide can come into contact with the light guiding core.
Thereby, a change in environment can be detected by analyzing the spectra of light having passed through the waveguide, and the waveguide can thus be used in a gas or fluid sensor. Even though the open hollow core optical waveguide is discussed in reference to its use in a gas sensor, it may obviously equally well be used in a fluid sensor. The hollow core may for example be filled by water or other fluids, thereby making it possible to analyze the fluid by studying the properties of light having propagated through a specific fluid.
Accordingly, an advantage of the present invention is that an optical fiber design allowing free communication between the hollow light guiding core and the outside environment without additional disturbance of the guidance of light is provided.
A further advantage of a hollow core waveguide according to various embodiments of the invention is that it may advantageously be used in a sensor in a hydrocarbon rich environment, where a conventional optical fiber may darken due to the creation of OH radicals. This will not be the case here as light is guided in an air-core.
Both the outer tubular element and the inner light guiding structure may advantageously be made from materials used in conventional optical fibers, such as silica. ln one embodiment of the invention, the inner hollow light guiding structure may comprise a tubular structure fixedly attached to the sidewall of the outer tubular element at a plurality of separate locations spaced apart from each other. One way to achieve a light guiding hollow core is to provide a second tubular structure within the outer tubular structure, and attaching the inner structure to the outer at specific locations, so that the distance between the two tubular structures is fixed. 10 15 20 25 30 According to one embodiment of the invention, the inner hollow light guiding structure may comprises a plurality of elongate elements arranged adjacent to each other, extending Iongitudinally along the length of a portion of the outer tubular element, and wherein at least two of the elongate elements are arranged at a distance from each other to form the opening of the inner hollow light guiding structure. A light guiding core may be provided through a plurality of tubular elongate element arranged adjacent to each other to form a confining circle within the outer tubular element. ln the same manner as described above, destructive and constructive interference determined by the dimension of the elongate elements determines which wavelengths may propagate in the light guiding core. Furthermore, by arranging at least two of the elements at a distance from each other in the circumferential direction, an opening is formed, an by aligning the opening with the opening in the outer tubular element, the environment outside of the optical waveguide can reach the core. ln one embodiment of the invention, a distance from an inner wall of the inner hollow light guiding structure to an inner wall of outer tubular element may advantageously be selected such that only light of selected wavelengths may propagate in said waveguide. lnterference between the inner wall of the outer tubular structure and the opposite wall of the inner hollow light guiding structure gives specific allowed wavelengths/modes due to destructive/constructive interference. Thus, the allowable wavelengths within the optical waveguide can be selected by selecting the distance between the outer tubular structure and the inner hollow light guiding structure.
Brief Description of the Drawinds These and other aspects of the present invention will now be described in more detail with reference to the appended drawings showing an example embodiment of the invention, wherein: 10 15 20 25 Fig. 1 schematically illustrates a waveguide according to an embodiment of the invention; Figs. 2a-b schematically illustrates a waveguide according to an embodiment of the invention; and Fig. 3 schematically illustrates a waveguide according to an embodiment of the invention.
Detailed Description of Preferred Embodiments of the lnvention Figs. 1a-b illustrates examples an open hollow core optical waveguide 100 for a gas sensor comprising an outer tubuiar element 102 having a sidewall, comprising an elongated opening 104 in said sidewall extending in the longitudinal direction along the length of a portion of said tubuiar element; a transparent inner hollow light guiding structure 106 forming a light guiding core, attached to an inner wall of said outer tubuiar element, said inner hollow light guiding structure comprising an elongated opening 108, arranged such that the light guiding core is in fluid communication with the elongated opening of said outer tubuiar element.
Typical dimensions are: outer diameter 125 um. Inner core 60 um.
Openings 1 um. The openings do not need to be aligned. Thickness: outer structure: 25 um. Inner: 1 um.
Fig. 2 and Fig. 3 shows an open hollow core optical waveguide 200, 300 for a gas sensor wherein the inner hollow light guiding structure comprises tubuiar structures 202, 302 fixedly attached to the sidewall of the outer tubuiar element at a plurality of separate locations. ln Fig. 3, the tubuiar structures 302 are spaced apart from each other.

Claims (8)

10 15 20 25 30 CLAIMS
1. An open hollow core optical waveguide (100, 200) for a gas sensor comprising: an outer tubular element (102) having a sidewall, comprising an elongated opening (104) in said sidewaii extending in the Iongitudinai direction along the length of a portion of said tubular element; a transparent inner hollow light guiding structure (106) forming a light guiding core, attached to an inner wall of said outer tubular element, said inner hollow light guiding structure comprising an elongated opening (108), arranged such that said light guiding core is in fluid communication with said elongated opening of said outer tubular element.
2. The optical waveguide according to claim 1, wherein said inner hollow light guiding structure comprises a tubular structure (202, 302) fixedly attached to said sidewaii of said outer tubular element at a plurality of separate locations spaced apart from each other.
3. The optical waveguide according to claim 1, wherein said inner hollow light guiding structure comprises a plurality of elongate elements arranged adjacent to each other, extending longitudinally along the length of a portion of said outer tubular element, and wherein at least two of said elongate elements are arranged at a distance from each other to form said opening of said inner hollow light guiding structure.
4. The optical waveguide according to claim 3, wherein said elongate element is a hollow circular element.
5. The optical waveguide according to any one of the preceding claims, wherein said outer tubular element is a circular element. 10 15 20
6. The optical waveguide according to any one of the preceding claims, wherein a distance from an inner wall of said inner hollow light guiding structure to an inner wall of outer tubular element is selected such that only light of selected wavelengths may propagate in said waveguide.
7. The optical waveguide according to any one of the preceding claims, in a first end optically coupled to a first optical fiber and in a second end optically coupled to a second optical fiber.
8. A gas sensor comprising: a light source configured to couple light into an optical waveguide according to any one of the preceding claims; and an optical receiver configured to receive light having passed through said optical waveguide; and a spectrum analyzer configured to analyze said received light. 10. method comprising the steps of: Method for manufacturing an optical waveguide gas sensor, said forming a perform comprising a tubular cladding; forming an elongated opening along a portion of the length of said tubular cladding; arranging a hollow light guiding structure within said tubular cladding; drawing an optical fiber from said perform. Ansökningsnummer: 1350785-0 I denna ansökan saknades patentkrav vid ingivningen.
SE1350785A 2013-06-27 2013-06-27 Optical waveguide gas sensor SE1350785A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
SE1350785A SE1350785A2 (en) 2013-06-27 2013-06-27 Optical waveguide gas sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE1350785A SE1350785A2 (en) 2013-06-27 2013-06-27 Optical waveguide gas sensor

Publications (2)

Publication Number Publication Date
SE1350785A1 true SE1350785A1 (sv) 2013-06-27
SE1350785A2 SE1350785A2 (en) 2015-11-10

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
SE1350785A SE1350785A2 (en) 2013-06-27 2013-06-27 Optical waveguide gas sensor

Country Status (1)

Country Link
SE (1) SE1350785A2 (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10133017B2 (en) * 2015-08-07 2018-11-20 Pgs Geophysical As Vented optical tube

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110501781B (zh) * 2019-08-30 2020-09-08 北京智芯微电子科技有限公司 波导的形成方法以及包含该波导的sf6气体无源传感器

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10133017B2 (en) * 2015-08-07 2018-11-20 Pgs Geophysical As Vented optical tube

Also Published As

Publication number Publication date
SE1350785A2 (en) 2015-11-10

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