WO1993018420A1 - Compositions de verre silice/germanium - Google Patents

Compositions de verre silice/germanium Download PDF

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Publication number
WO1993018420A1
WO1993018420A1 PCT/GB1993/000462 GB9300462W WO9318420A1 WO 1993018420 A1 WO1993018420 A1 WO 1993018420A1 GB 9300462 W GB9300462 W GB 9300462W WO 9318420 A1 WO9318420 A1 WO 9318420A1
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WO
WIPO (PCT)
Prior art keywords
refractive index
glass
silica
fibre
germania
Prior art date
Application number
PCT/GB1993/000462
Other languages
English (en)
Inventor
Benjamin James Ainslie
Douglas Lawrence Williams
Jonathan Richard Armitage
Raman Kashyap
Graeme Douglas Maxwell
Original Assignee
British Telecommunications Public Limited Company
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
Priority claimed from GB929205090A external-priority patent/GB9205090D0/en
Priority claimed from GB929221951A external-priority patent/GB9221951D0/en
Application filed by British Telecommunications Public Limited Company filed Critical British Telecommunications Public Limited Company
Publication of WO1993018420A1 publication Critical patent/WO1993018420A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/124—Geodesic lenses or integrated gratings
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00—Other methods of shaping glass
    • C03B19/14—Other methods of shaping glass by gas- or vapour- phase reaction processes
    • C03B19/1453—Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/018—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
    • C03B37/01853—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C13/00—Fibre or filament compositions
    • C03C13/04—Fibre optics, e.g. core and clad fibre compositions
    • C03C13/045—Silica-containing oxide glass compositions
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/06—Glass compositions containing silica with more than 90% silica by weight, e.g. quartz
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C4/00—Compositions for glass with special properties
    • C03C4/04—Compositions for glass with special properties for photosensitive glass
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
    • G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
    • G02B6/0208—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response
    • G02B6/021—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response characterised by the core or cladding or coating, e.g. materials, radial refractive index profiles, cladding shape
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
    • C03B2201/31—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with germanium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/30—Doped silica-based glasses containing metals
    • C03C2201/31—Doped silica-based glasses containing metals containing germanium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2203/00—Production processes
    • C03C2203/50—After-treatment
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
    • G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
    • G02B6/02123—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating
    • G02B6/02133—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating using beam interference

Definitions

  • This invention relates to reflection waveguides and, more particularly, to silica/germania glass compositions which are adapted to receive refractive index modulation, e. g. for making reflection waveguides.
  • Reflection waveguides have a path region with a modulated refracted index.
  • the waveguiding structure is often in the form of a fibre or a planar waveguide.
  • the modulation takes the form of alternare regions of higher and lower refractive index. When radiation traverses the modulation, it is selectively reflected.
  • the period of the refractive index modulation is usually equal to the wavelength to be reflected or to a multiple or sub-multiple of said wavelength. Thus periods in the range 0.25 to 0.6 ⁇ m preferentially reflect selected wavelengths within the range 800 - 1650 ⁇ m.
  • Reflection gratings have many applications in optical signalling.
  • a reflection grating can be associated with a fibre laser in order to narrow.the lasing band.
  • the grating can be used for the selective removal of unwanted wavelengths.
  • refractive index modulation has other applications, e. g. to achieve phase matching in waveguides and to control spot size and/or shape of a guided mode.
  • Refractive index modulation is conveniently produced by an optical process in which a photosensitive glass is exposed to radiation which causes an adequate change in its refractive index.
  • the radiation has higher and lower intensities corresponding to the intended modulation of the refractive index of the glass.
  • the mutual interference of two beams of radiation produces the variation of intensity.
  • Silica/germania glasses are widely used in optical telecommunications and it has been noticed that these glasses have an optical absorption band extending approximately over the wavelength range 225 - 275 nm and exposure to radiation within this band increases the refractive index of the silica/germania composition. The peak of the band occurs at a wavelength which is close to 240 nm. It has, therefore, been proposed to produce refractive index modulation, e.
  • the sensitivity of the glass is important, and this invention relates to a form of silica/germania glass which is particularly sensitive to said radiation.
  • the glass according to the invention can be recognised by the height of the peak which displays its maximum absorption at a wavelength close to 240 nm.
  • the peak height is related to the Ge content of the glass.
  • the composition according to the invention is in a reduced state and the Ge may be present in various forms, e. g. GeO as well as Ge0 2 . Therefore the peak height should be related to the total Ge content of the glass .composition, and the glass is characterised by an absorption of at least 200 dB/cm/wt% of Ge, preferably at least 300 dB/cm/wt% of Ge and most preferably at least 500 dB/cm/wt% of Ge, said absorption being measured at 240 nm.
  • the glass compositions according to the invention are obtained by subjecting the glass to non-oxidising conditions, eg by heating the glass in the presence of a non-oxidising atmosphere.
  • the non-oxidising atmosphere might be provided by an inert gas such as nitrogen or helium or the other noble gases.
  • a reducing atmosphere eg hydrogen, may be used.
  • the treatment of glass in the solid phase depends upon the diffusion of the treatment gas from the surface to the interior of the glass. It is thus desirable to conduct the heating under conditions such that there are only short, e. g. below 250 ⁇ m, path lengths from the centre of the glass composition to the atmosphere. • This can be achieved by heating the glass composition in the form of a fine powder, or while it is in a porous state. As an alternative, the glass composition can be heated while it is in the form of a thin film, e. g. up to 250 ⁇ m thick.
  • Glass compositions in accordance with the invention are primarily intended for use in waveguiding structures having path regions of small dimension, e. g. below 50 ⁇ m, so that the dimensions are favourable for reduction as described above.
  • many processes used to prepare waveguides initially deposit the glass in porous layers.
  • the physical states encountered during the preparation of a waveguiding structure favour chemical reaction with a gaseous atmosphere.
  • waveguides and reflection gratings in accordance with the invention are produced following conventional methods with non-oxidising treatment incorporated at the appropriate stage.
  • the appropriate stage for waveguiding structures in the form of a fibre usually occurs during the preparation of a path region precursor and before the structure is drawn into fibre.
  • the non-oxidising treatment is usually most appropriate as the final stage of processing, that is after the guides have been fully formed.
  • the glass is first formed as small particles which coalesce to give a porous structure.
  • the glass displays what is in effect a large surface area whereby its reactivity with gaseous reactants is enhanced. It is convenient, in accordance with this invention, to reduce the glass while it is in this form but photosensitivity is associated with mild reduction, e. g. with oxygen deficient glasses.
  • photosensitivity is associated with mild reduction, e. g. with oxygen deficient glasses.
  • non-oxidising atmospheres as described above. It is also appropriate to maintain the non-oxidising conditions while the porous structure is consolidated. After consolidation, the photosensitive region will be located in the centre of a rod or fibre and the outer layers of this structure provide substantial protection for the reduced composition and this protection makes it unlikely that the reduced composition will become reoxidised.
  • Planar waveguides are deposited in layers and various shaping processes may be included. It is particular important to make path regions photosensitive and it is unlikely that a path region will be the last deposited layer of" a structure.
  • a confining region is usually deposited after a path region. Even if no final confining region is required it is usually appropriate to deposit a capping layer for mechanical protection.
  • a capping layer for mechanical protection.
  • the waveguide structure includes a silica/germania glass composition in accordance with the invention and a reflection grating is formed in said glass composition.
  • the examples will refer to the accompanying drawings in which: -
  • Figure 1 illustrates the exposure of a waveguide to radiation in order to produce a reflection grating
  • Figure 2 is a schematic showing a cross-section through a planar waveguide structure.
  • Figure 3 shows the absorption spectrum of a 4mole% Ge0 2 /Si0 2 layer before hydrogenation (curve (a)) and after hydrogenation (curve (b)),
  • Figure 4 shows the transmission spectrum of a 3cm long single mode planar waveguide before hydrogenation (curve (a) ) and after hydrogenation (curve (b)),
  • Figure 5 shows the transmission spectrum of the planar waveguide of Figure 3 after a reflection grating has been written in the path region of the waveguide.
  • the invention comprises a waveguiding structure in the form of a fibre having a path region formed of a silica/germania glass composition in accordance with the invention.
  • Example 1 It is convenient to divide Example 1 into two stages. In the first stage, a photosensitive fibre is prepared in accordance with the method of the invention.
  • the photosensitive fibre is treated with radiation in order to prepare a reflection grating in accordance with the invention.
  • the fibre according to the invention was prepared by a modification of the well-known inside deposition process for making optical fibre.
  • the appropriate number of layers are deposited on the inner surface of a tube which serves as a substrate.
  • the outermost layers are deposited first and the innermost layers are deposited last.
  • the tube is collapsed into a solid rod, and the solid rod is drawn into fibre.
  • the heating is carried out by causing a flame to traverse along the length of the tube.
  • the flame heats a short section of the tube so that a portion, about 20 mm long, is heated to the working temperature.
  • This technique of heating is used for all stages of the process, i. e. for the deposition, for consolidating porous layers to solid layers and for the collapse of the tube. Multiple passes are used at all stages of the process.
  • the speed (in mm/min) at which the flame traverses is given in the following examples.
  • the time taken to traverse 20 mm is given.
  • the starting tube was made of pure silica. It had an external diameter of 18 mm and an internal diameter of 15 mm.
  • the deposited cladding took the form of Si0 2 wi'th phosphous and fluorine to reduce its melting point.
  • Six layers of cladding were deposited, and the conditions used for the deposition of each layer were as follows: -
  • the flame traversed at 110 mm/min i.e. the time to traverse 20 mm was about 10 seconds.
  • the working temperature was approximately 1525"C. It is emphasised, that after each traverse, each cladding layer was in the form of a clear glass layer before the next layer was deposited.
  • the cladding layers are considered to be part of the substrate tube upon which the core layers were deposited.
  • the deposition of cladding layers as described above could be omitted.
  • the main purpose of the cladding layers is to reduce the risk of contamination from the original tube affecting core layers.
  • the flame traversed at 110 mm/min i.e. the same as for the cladding
  • the working temperature was only 1220'C. This lower temperature ensured that the core layers remained in a porous condition for reduction.
  • the procedure was carried out in five stages each of which comprised heating the porous core precursor in the presence of an atmosphere of helium which was flowed through the tube at a rate of 2 litres/min. During each of the five stages, the flame traversed at 110 mm/min whereby, for each portion of glass, a total heating time of about 50 seconds was achieved.
  • the working temperatures used in each of the five stages were as follows: -
  • the core precursor was converted from a porous layer about 250 ⁇ m thick in an oxidised state into a thin consolidated layer about 5 ⁇ m thick in a less oxidised state.
  • the glass was reduced because the atmosphere was helium.
  • the tube was collapsed into a solid rod.
  • the collapse was also carried out in the presence of helium so that the reducing conditions were maintained.
  • the mechanics of the collapse are substantially conventional (but, in normal practice, the atmosphere inside the tube contains oxygen).
  • stage 5 The flow rate in stage 5 is zero because the tube is converted to a rod and flow becomes impossible. Nevertheless, the atmosphere in the remaining bore is still helium.
  • the preform prepared as described above was drawn into fibre of 120 ⁇ m diameter at a temperature of 2,000"C.
  • the fibre was produced at a rate of 18 metres/sec.
  • the absorption at 240 nm was measured by passing light longitudinally through samples of the fibre.
  • the samples had a path length of 20 ⁇ m.
  • the absorption was 900 dB/ ⁇ m/wt%. (The radiation intensities used to measure the absorbtion are too low to affect the refractive index. )
  • Short lengths of the fibre described above were converted into reflection waveguides using the technique illustrated in the drawing.
  • a short portion 14 of the fibre 15 was illuminated by a source 10.
  • This radiation was, in the first instance, produced by a Ar + laser, frequency doubled to give output at a wavelength of 244 nm.
  • the beam from the source 10 was directed onto a splitter 11 so that two beams were directed onto mirrors 12 and 13.
  • the mirrors 12 and 13 caused the beams to converge onto the target section 14.
  • an interference pattern is produced with alternating regions of higher and lower intensity.
  • the region 14 (whereon the beams are focused) is affected by the beams and the refractive . index is in ⁇ reased in the areas of high intensity.
  • a reflection grating is produced in the region 14.
  • the spacing of the interference pattern is affected by the angle at which the two beams intersect one another, and hence the spacing of the grating can be adjusted by adjusting the relative position of the splitter 11 and the mirrors 12 and 13.
  • the fibre was subj cted to the interference pattern for 10 mins (i.e. 10 mins writing time) under a continuous power of 5 mW in the beams which impinge on the core of the fibre.
  • the "RIC” is the relative index change and it is calculated as [(index modulation)/ ⁇ n) ] x 100 to convert to percentage.
  • ⁇ n is the direct measure of the change of refractive index and it is approximately proportional to the amount of germania in the core. ince all three fibres were exposed to the same radiation, the index modulation could be taken as a measure of the photosensitivity of the fibre. However, it is easier to achieve a larger modulation if the fibre contains more germania. Hence the RIC involves both the concentration of the germania measured by ⁇ n and the effect of the radiation.
  • a planar waveguide according to the invention was prepared b a modification of the well known Flame Hydrolysis Process. Once a planar waveguiding structure has been formed in a conventional way by this technique it was reduced by exposure to a non-oxidising atmosphere in accordance with the invention.
  • Flame hydrolysis is a process which enables layers of a specific glass composition to be deposited, generally onto a planar silicon or fused silica substrate. Waveguides can be formed form these layers by etching path regions defined, for example by photolithography, from the layers.
  • Flame hydrolysis is carried out at high temperature in a oxygen/hydrogen flame, which provides the water for the hydrolysis part of the reaction. Reagents are introduced into the flame in order to produce the desired layers.
  • SiCl 4 is introduced to the flame, to produce Si0 2 .
  • ancillary reagents In order to increase the refractive index of the Si0 2 it is necessary to introduced ancillary reagents into the flame, and three important ancillary reagents are GeCl 4 which produces Ge0 2 ,
  • reagents used to vary the refractive index can be used to reduce the melting point of the deposited layer.
  • Reagents to introduce a lasing additive may also be used.
  • the consolidated layer is etched to give a desired path configuration. This etching is achieved by conventional photolithography followed by etching, e. g. reactive ion etching.
  • the Flame Hydrolysis Process was used to fabricate the planar waveguide structure shown schematically in Figure 2.
  • the planar waveguide comprises a silicon substrate 1 approximately 1mm thick, a Si0 2 thermal oxide layer 2 approximately lO ⁇ m thick, a buffer layer 3 approximately 15 ⁇ m thick, a path region 4 approximately 6 ⁇ m square in cross-section, and a cladding layer 5 approximately 15 ⁇ m thick.
  • the glass compositions of respectively, the buffer, path and cladding regions are choosen so that their melting points decrease in that order. This ensures that a previously deposited region is dimensionally stable during the deposition of a subsequent region.
  • the buffer layer 3 comprises approximately 2 to 4 wt% B 2 0 3 and 1 to 3 wt% P 2 0 5 doped Si0 2 .
  • the path region 4 comprises approximately 4 to 10 wt% Ge0 2 , 2 to 5 wt% B 2 0 3 and 1 to 3 wt% P 2 0 5 doped Si0 2 .
  • the cladding region 5 comprises approximately 10 to 20 wt% B 2 0 3 and 5 to 10 wt% P-0 5 doped Si0 2 .
  • the proportions of B 2 0 3 and 2 0 5 in the .cladding and buffer layer are ⁇ hoosen so that these two layers have approximately the same refractive index.
  • the path region 4 is thus surrounded by material of uniform refractive index, which index is lower than the refractive index of the path region and which acts to confine optical radiation to the path region.
  • the completed waveguide structure was then placed in an oven at 750°C and surrounded by hydrogen at atmospheric pressure for one hour.
  • This hydrogenation schedule was selected to allow hydrogen to diffuse a distance of greater than 1mm, and so the whole of the waveguide structure should be affected by the treatment.
  • the hydrogenation treatment increases the absorbtion at 240nm of the glass forming the waveguide and, in accordance with the invention, increases the photosensitivity of the glass.
  • Figure 3 shows the absorption spectrum of a layer of path region glass, containing approximately 4mole% Ge0 2 , before and after hydrogenation.
  • the 240nm absorption band measured on the untreated sample (labelled (a) in Figure 3) was extremely small (approximately 2dB/cm) and planar waveguides based on these prior art low UV absorbing layers show negligible photosensitivity.
  • the absorption of the treated path region layer (labelled (b) in Figure 3) at 240nm is substantially higher, having a peak absorption of approximately 12, OOOdB/cm (corresponding to approximately 2, 500dB/cm/wt% of Ge). It is believed that high absorption levels at 240nm in planar Ge0 2 /Si0 2 layers give a strong indication of their potential photosensitivity because the extent to which this UV band can be bleached and the UV absorption spectrum changed, directly relates to any index change via the Kramers-Kronig relationship.
  • Figure 4 shows the transmission spectrum of the 3cm planar waveguide before and after hydrogenation.
  • the untreated guide (labelled (a) in Figure 4) shows a relatively flat wavelength response over the range 1.0-1.6 ⁇ m and the loss of the guide in this region is approximately 0. IdB/cm.
  • the transmission spectrum (labelled (b) in Figure 4) shows strong attenuation towards shorter wavelengths, although in the 1.5 ⁇ m region the guide is still low loss. Only a relatively weak shoulder at 1.38 ⁇ m is apparent indicating that OH absorption should not significantly affect the loss in planar devices.
  • the increase in attenuation could be due to a low energy tail from defect related absorptions or to scatter. It is anticipated that by optimising the fabrication conditions this loss can be reduced so that grating devices can be formed for use in the 1.3 ⁇ m window in addition to the 1.5 ⁇ m window.
  • a reflection grating was written into the planar waveguide using the arrangement shown in Figure 1, a continuous power level of 25mW, and an exposure time of 40 minutes.
  • Figure 5 shows the transmission spectrum of the waveguide after grating writing.
  • planar waveguides have such low levels of photosensitivity that it is not possible to write a grating of any significant reflectivity in such waveguides for comparison with planar waveguide reflection gratings according to the present invention.
  • Gratings formed according to the invention have been found to be stable, showing no change in reflectivity after several weeks in the laboratory at room temperature. In addition after heating samples in air for 15 hours at 100°C followed by a further 15 hours at 150°C there was no change in the grating reflectivity.

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  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • General Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
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  • Optical Integrated Circuits (AREA)

Abstract

On a démontré que les verres silice/germanium sous forme réduite sont plus sensibles au rayonnement dans la bande 225- 275 nm et, donc, que les verres silice/germanium réduits sont notamment adaptés pour recevoir une modulation d'indice de réfraction, par exemple pour réaliser des grilles type réfléchissantes. Les compositions silice/germanium réduites sont identifiées par une absorption supérieure à 200 dB/cm/% en poids de GE. On obtient les compositions réduites en soumettant le verre à atmosphère non-oxydante, par exemple à l'hélium de préférence, alors qu'il est toujours dans un état poreux ou sous forme d'une couche mince.
PCT/GB1993/000462 1992-03-09 1993-03-05 Compositions de verre silice/germanium WO1993018420A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
GB9205090.5 1992-03-09
GB929205090A GB9205090D0 (en) 1992-03-09 1992-03-09 Silica germania glass compositions
EP92305783 1992-06-24
EP92305783.0 1992-06-24
GB9221951.8 1992-10-20
GB929221951A GB9221951D0 (en) 1992-10-20 1992-10-20 Silica germania glass compositions

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WO1993018420A1 true WO1993018420A1 (fr) 1993-09-16

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995022068A1 (fr) * 1994-02-14 1995-08-17 The University Of Sydney Reseau optique
WO1996016344A1 (fr) * 1994-11-18 1996-05-30 The University Of Sydney Procede destine a induire des proprietes electro-optiques dans un materiau a transmission optique ou a ameliorer de telles proprietes
GB2295904A (en) * 1994-12-09 1996-06-12 Balzers Hochvakuum Diffraction gratings in optical components
EP0747327A1 (fr) * 1995-06-07 1996-12-11 Corning Incorporated Procédé de traitement thermique et de consolidation de préformes en silice en vue de réduire les dommages optiques produits par l'application des lasers
EP0784217A1 (fr) * 1995-07-28 1997-07-16 Nauchny Tsentr Volokonnoi Optiki Pri Institute Obschei Fiziki Imeni A.M.Prokhorova Rossyskoi Akademii Nauk Laser raman a fibres optiques, reseau de bragg a fibres optiques et procede de modification de l'indice de refraction dans un verre de germanosilicate
US6058231A (en) * 1998-02-13 2000-05-02 3M Innovative Properties Company Boron-doped optical fiber
US6201918B1 (en) 1996-12-20 2001-03-13 Corning Incorporated Athermalized codoped optical waveguide device
EP1174742A1 (fr) * 1995-07-28 2002-01-23 Nauchny Tsentr Volokonnoi Optiki Pri Institute Obschei Fiziki Rossiiskoi Akademii Nauk Réseau de Bragg à fibres optiques et procédé de modification de l'indice de réfraction dans un verre de germanosilicate
WO2003102650A1 (fr) * 2002-05-30 2003-12-11 Optoplan As Procede de modification de la composition chimique de dispositifs optiques
US6832026B2 (en) 2001-07-20 2004-12-14 Nufern Optical fiber having high temperature insensitivity over a temperature range centered on a selected temperature and method of making same
US6904214B2 (en) 2002-05-14 2005-06-07 Nufern Method of providing an optical fiber having a minimum temperature sensitivity at a selected temperature
CN111556977A (zh) * 2018-01-11 2020-08-18 住友电气工业株式会社 光学器件和光学器件的制造方法

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US5830622A (en) * 1994-02-14 1998-11-03 The University Of Sydney Optical grating
WO1995022068A1 (fr) * 1994-02-14 1995-08-17 The University Of Sydney Reseau optique
WO1996016344A1 (fr) * 1994-11-18 1996-05-30 The University Of Sydney Procede destine a induire des proprietes electro-optiques dans un materiau a transmission optique ou a ameliorer de telles proprietes
US5966233A (en) * 1994-11-18 1999-10-12 University Of Sydney Inducing or enhancing electro-optic properties in optically transmissive material with simultaneous UV irradiation and electric field application
GB2295904B (en) * 1994-12-09 1999-01-20 Balzers Hochvakuum Diffraction gratings in optical waveguide components
GB2295904A (en) * 1994-12-09 1996-06-12 Balzers Hochvakuum Diffraction gratings in optical components
US5675691A (en) * 1994-12-09 1997-10-07 Balzers Aktiengesellschaft Diffraction gratings in optical waveguide components and production method thereof
EP0747327A1 (fr) * 1995-06-07 1996-12-11 Corning Incorporated Procédé de traitement thermique et de consolidation de préformes en silice en vue de réduire les dommages optiques produits par l'application des lasers
US5735921A (en) * 1995-06-07 1998-04-07 Corning Incorporated Method of reducing laser-induced optical damage in silica
US5838700A (en) * 1995-07-28 1998-11-17 Nauchny Tsentr Volokonnoi Optiki Pri Institute Obschei Fiziki Rossiiskoi Akademii Nauk Raman fibre laser, bragg fibre-optical grating and method for changing the refraction index in germanium silicate glass
EP0784217A1 (fr) * 1995-07-28 1997-07-16 Nauchny Tsentr Volokonnoi Optiki Pri Institute Obschei Fiziki Imeni A.M.Prokhorova Rossyskoi Akademii Nauk Laser raman a fibres optiques, reseau de bragg a fibres optiques et procede de modification de l'indice de refraction dans un verre de germanosilicate
EP0784217A4 (fr) * 1995-07-28 2000-10-25 Nauchny Ts Volokonnoi Optiki P Laser raman a fibres optiques, reseau de bragg a fibres optiques et procede de modification de l'indice de refraction dans un verre de germanosilicate
EP1174742A1 (fr) * 1995-07-28 2002-01-23 Nauchny Tsentr Volokonnoi Optiki Pri Institute Obschei Fiziki Rossiiskoi Akademii Nauk Réseau de Bragg à fibres optiques et procédé de modification de l'indice de réfraction dans un verre de germanosilicate
US6201918B1 (en) 1996-12-20 2001-03-13 Corning Incorporated Athermalized codoped optical waveguide device
US6058231A (en) * 1998-02-13 2000-05-02 3M Innovative Properties Company Boron-doped optical fiber
US6832026B2 (en) 2001-07-20 2004-12-14 Nufern Optical fiber having high temperature insensitivity over a temperature range centered on a selected temperature and method of making same
US6904214B2 (en) 2002-05-14 2005-06-07 Nufern Method of providing an optical fiber having a minimum temperature sensitivity at a selected temperature
WO2003102650A1 (fr) * 2002-05-30 2003-12-11 Optoplan As Procede de modification de la composition chimique de dispositifs optiques
CN111556977A (zh) * 2018-01-11 2020-08-18 住友电气工业株式会社 光学器件和光学器件的制造方法

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