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
  • G02B6/02—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
  • G02B6/02209—Mounting means, e.g. adhesives, casings
• • 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
  • C03C27/00—Joining pieces of glass to pieces of other inorganic material; Joining glass to glass other than by fusing
  • C03C27/06—Joining glass to glass by processes other than fusing
  • C03C27/10—Joining glass to glass by processes other than fusing with the aid of adhesive specially adapted for that purpose
• • 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
  • C03C3/062—Glass compositions containing silica with less than 40% silica by weight
  • C03C3/064—Glass compositions containing silica with less than 40% silica by weight containing boron
• • 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
  • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
  • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
• • 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
  • C03C3/097—Glass compositions containing silica with 40% to 90% silica, by weight containing phosphorus, niobium or tantalum
• • 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
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/24—Fusion seal compositions being frit compositions having non-frit additions, i.e. for use as seals between dissimilar materials, e.g. glass and metal; Glass solders
• • 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
  • G02B6/02171—Refractive index modulation gratings, e.g. Bragg gratings characterised by means for compensating environmentally induced changes
  • G02B6/02176—Refractive index modulation gratings, e.g. Bragg gratings characterised by means for compensating environmentally induced changes due to temperature fluctuations
  • G02B6/0218—Refractive index modulation gratings, e.g. Bragg gratings characterised by means for compensating environmentally induced changes due to temperature fluctuations using mounting means, e.g. by using a combination of materials having different thermal expansion coefficients

Definitions

• Telecommunication article having a seal produced with a copper aluminosilicate sealing glass, and method of producing the glass.
• sealing glasses composed essentially of oxides of copper, aluminum and silicon, may have coefficients of thermal expansion (CTEs) less than 10x10 "7 /°C. over a broad temperature range. This property has led to such sealing glasses being proposed for joining fused silica, quartz and low-expansion glass-ceramic, structural components. In particular, such glasses have been proposed for use in constructing large mirrors such as used in astronomy studies.
• CTEs coefficients of thermal expansion
• the invention resides in part in a telecommunications device comprising a substrate having a low positive, or negative, thermal expansion coefficient, a low-expansion optical component, and a fusion seal that maintains the substrate and the optical components in intimate contact, the fusion seal being a copper alumino-silicate glass that has a coefficient of thermal expansion (CTE) less than 20x10 "7 /°C.
• CTE coefficient of thermal expansion
• the invention also resides in a method of producing a copper aluminosilicate glass in which the copper is essentially present in the cuprous state, the method comprising mixing a glass batch containing cuprous oxides as a source of copper, melting the glass batch while maintaining the melt in a mildly oxidized condition during melting to avoid formation of copper particles.
• the invention further comprehends a copper aluminosilicate sealing glass that has a softening point less than 900° C, that has a CTE less than about 20x10 "7 /°C, that has a composition consisting essentially of, as calculated in weight percent on an oxide basis, 33-70 SiO 2 , 10-35% AI 2 O 3 , 10- 40% Cu 2 O, 0-10% P 2 O 5 , 0-10% B 2 O 3 , 33-70% SiO 2 +B 2 O 3 , and 10-35% AI 2 O 3 +B 2 O 3 , the copper oxide being essentially completely in the cuprous state.
• FIGURE 1 is a schematic drawing illustrating a simple, telecommunication device in accordance with the invention.
• FIGURE 2 is a graphical representation of the glass-forming area of the ternary, Cu 2 O-AI 2 O 3 -SiO 2 system at a melting temperature of 1500° C.
• FIGURE 3 is a graphical representation showing the mismatch between a glass of the present invention and fused silica.
• the present invention arose from a search for copper aluminosilicate sealing glasses that would be more effective, and/or advantageous, in maintaining an optical component in intimate contact with a supporting substrate. More particularly, the article that required the improved sealing glass was an optical waveguide grating device as described in related application S.N. . However, the invention finds broader application in joining optical components where a low-expansion, sealing glass is required. These include optical waveguide fibers and planar components used in telecommunication equipment.
• FIGURE 1 is a schematic, side view of a simple, optical waveguide device 10 illustrating the article of the invention.
• Device 10 comprises a substrate member 12 that supports an optical fiber 14, and glass members 16 that secure fiber 14 to substrate 12.
• Glass members 16 may form a fusion seal between fiber 14 and substrate 12. Alternatively, they may be applied over fiber 14, and sealed to substrate 12, to securely maintain fiber 14 in intimate contact with substrate 12.
• Optical communication occurs entirely through fiber 14.
• successful communication may depend on fiber 14 being held in a fixed position, and/or under a degree of tension.
• substrate 12 should have a coefficient of thermal expansion no greater than that of the fiber, and preferably lower.
• the substrate must have a lower CTE, and may have a negative value. This permits the substrate to contract to a lesser degree, or even to expand, on cooling from the glass sealing temperature. This creates a degree of tension in fiber 14.
• FIGURE 2 is a graphical representation of the glass-forming region at 1500° C. for the ternary system CuO-AI 2 O 3 -SiO 2 .
• the bottom line represents CuO content
• the left hand side represents SiO 2 content
• the right hand side represents AI 2 O 3 content.
• the apex represents 100 cation percent SiO 2 .
• the experimental melts, upon which the graphical representation is based, were batched with CuO. However, the same compositions batched with Cu 2 O should occupy the same region as explained later.
• either B 2 O 3 or P 2 O 5 may be substituted for either AI 2 O 3 or SiO 2 .
• the substitution may be in an amount up to about 10% by weight. Preferably, the substitution is in an amount of 1-4%.
• the present copper aluminosilicate sealing glasses consist essentially of, as calculated on an oxide basis in weight percent,
• the glasses of the present invention exhibit softening points below 900°
• Preferred glasses will have softening points on the order of 800° C. and not over 850° C. This is in contrast to previously available commercial glasses having softening points substantially above 900° C. Thus, a glass currently available has a softening point of 915° C.
• the glasses will have CTEs below 20x10 "7 /°C. over the temperature range of 25-500° C. Generally, these values are below 15x10 "7 /°C, and preferred glasses are below 10x10 "7 /°C.
• the glasses will melt and pour at temperatures on the order of 1500° C. These properties are optimized in a family of preferred compositions, again in weight percent on a calculated oxide basis, that consist essentially of,
• a feature of the present invention is based on the discovery that the formation of copper particles can be avoided. This involves including a small amount of a mild oxidizing agent, such as a nitrate, or a sulfate, in the batch from which the glass is melted. This provides a mildly oxidizing condition in the melt that is sufficient to avoid appreciable reduction to, and precipitation of, copper metal. At the same time, there appears to be no effect on other properties, in particular, the low softening point and expansion coefficient.
• a mild oxidizing agent such as a nitrate, or a sulfate
• a metal nitrate or sulfate is included in the glass batch.
• a sulfate of copper, copper nitrate, or aluminum nitrate is used, such as up to 5 weight percent of CuSO 4 5H 2 O, Cu(NO 3 ) 2 3H 2 O, or AI(NO 3 ) 3 -9H 2 O.
• other sources such as NH 4 NO 3 and most nitrates and/or sulfates of transition metals, may be employed.
• the copper aluminosilicate glasses just described may be used in various forms in telecommunication devices. Thus, they may be drawn as cane, tubing or fiber for packaging purposes. They may also be pulverized to form a glass sealing frit for use in conventional manner.
• TABLE I shows several compositions, together with CTEs and softening points, that illustrate the invention. The compositions are shown in weight percent.
• Oxide (wt. %) 1 2 3 4 5 6 7 8 9
• Composition 1 is presently preferred because of its low CTE.
• This composition, and compositions 3-7 illustrate embodiments within the preferred composition ranges and having CTEs below 10x10 "7 /°C.
• Compositions 8 and 9 illustrate compositions within the broad ranges. They demonstrate low and high Cu 2 O contents, respectively, and, conversely, high and low contents of SiO 2 .
• TABLE II shows the batches melted to produce the glasses having the compositions shown in TABLE I. In this case, the materials are in parts by weight.
• compositions 1 and 2 illustrate the effect of Cu 2 O vs. CuO as batch ingredients.
• the compositions are essentially the same, but the CTE of the glass from batch 2 is double that of the glass from composition 1. This indicates the effectiveness of using cuprous oxide as a batch ingredient.
• the batches were formulated and mixed in conventional manner. Each batch was placed in a silica crucible, and the crucible placed in an electric furnace operating at about 1500° C. At the end of a four hour melting period, the melts were poured into molds to provide test pieces for chemical and physical analyses.
• FIGURE 3 is a graphical representation of an inventive feature of particular interest. Temperature, in ° C, is plotted on the horizontal axis. Expansion mismatch vs. fused silica, in parts per million (ppm), is plotted on the vertical axis. The central, horizontal line represents zero mismatch over the temperature range 0-600° C.
• the curve shown in FIGURE 3 is based on measurements made on an inverse sandwich seal between fused silica and a sealing frit having the composition of Example 1 in TABLE I. The data plotted were measured as the seal was cooled from a sealing temperature of about 550° C. to ambient. The mismatch between the present glass and fused silica is consistently negative.
• the degree of mismatch that can be tolerated in a seal is dependent on size and geometry of the seal and of the components being sealed. For relatively small seals, such as contemplated here, a mismatch up to about 400 ppm between a commercial sealing glass and fused silica has been deemed tolerable.
• mismatch in the range of 100-200 ppm can be obtained.
• mismatch is below 100 ppm, a particularly favorable condition. This is illustrated in the preferred example of FIGURE 3.
• the maximum mismatch is on the order of 150 ppm.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Geochemistry & Mineralogy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Ceramic Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Glass Compositions (AREA)
• Light Guides In General And Applications Therefor (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1999
  • 1999-10-21 CN CN 99813013 patent/CN1325367A/zh active Pending
  • 1999-10-21 CA CA002349866A patent/CA2349866A1/en not_active Abandoned
  • 1999-10-21 WO PCT/US1999/024884 patent/WO2000027768A1/en not_active Application Discontinuation
  • 1999-10-21 AU AU12259/00A patent/AU1225900A/en not_active Abandoned
  • 1999-10-21 EP EP99971786A patent/EP1144325A1/de not_active Withdrawn
  • 1999-10-21 JP JP2000580952A patent/JP2002529780A/ja not_active Withdrawn

Non-Patent Citations (1)

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