Deutschetelekom Ag

Heraeus Quarzglas Gmbh

Electronic Production Partners Gmbh

Walter Heitmann

Karl-Friedrich Klein

Wolfgang Dultz

Hans W P Koops

Heinrich Stenger

A photonic crystal is a three-dimensional dielectric structure which is opaque to electro-magnetic radiation within a given wavelength irrespective of the direction of incidence. The photonic crystal may include, for instance, a matrix-type arrangement of free-standing dielectric micro-columns or cylinders having small diameters. The micro-columns or cylinders are placed on a substrate whose thermal expansion coefficient between 60&#xb0; C. and 85&#xb0; C. is at least 50% lower than the thermal expansion coefficients of quartz glass, enabling the thermal expansion of the substrate to be kept to a minimum even when high temperature variations occur. The distance between the micro-columns supported by the substrate or the microcylinders of the photonic crystal varies only to a small amount. The optical characteristics are essentially more stable than those of photonic crystals with a quartz glass substrate. Glass ceramics or, for example, Zerodur&#xae; may be used as a substrate.

Photonic crystals

The invention relates to an optical waveguide (optical fiber) based on quartz glass having reduced internal mechanical stresses. In prior art optical waveguides, the internal mechanical stresses are primarily due to the production process, namely due to the difference of the linear thermal coefficients of expansion of the core and sheathing material during the cooling of the fiber and due to the drawing itself. In an inventive optical waveguide, the difference of the linear thermal coefficients of expansion of the core and/or sheathing material is selected by means of an appropriate doping of the core and sheathing material. This selection is made so that the internal mechanical stresses, which are caused by the cooling during the production process, are significantly reduced or eliminated and/or they counteract the stresses caused by the drawing. The invention provides that all of tile internal stresses inside the optical waveguide are significantly reduced, minimized or eliminated with regard to those of prior art optical waveguides. The advantageous effects resulting therefrom include a lower attenuation and improved PMD values compared to prior art optical waveguides.

Fused silica-based optical waveguide and method for its manufacture

A method for manufacturing preforms for polymer optical fibers having an index of refraction that is variable over the radius, in which a core of preform material is coated with coating material for forming the preform until a predefinable diameter is reached, the refractive index of the coating material being varied in conformance with a predefinable profile along the radius of the emerging preform.

Method for manufacturing preforms for polymer optical fibers

Method using photonic crystals for the dispersion compensation of optical signals of different wavelengths which are transmitted together

Optical waveguides made of quartz glass with reduced infrared absorption and reduced attenuation coefficients are made of glass material composed of atoms having mass numbers higher than that of the natural isotope distribution. The quartz glass or doped quartz glass is made of silicon atoms, of which most or all have the mass numbers 29 and/or 30, as well as of oxygen atoms, of which most or all are composed of isotopes with the mass numbers 17 and/or 18. Atoms of the Ge isotope are preferably used for doping with germanium atoms having higher mass numbers than in the natural isotope mixture. Glass with atoms of preferably Si and/or O are preferably used for optical waveguides based on quartz glass having attenuation coefficients below 0.15 dB/km. As indicated, such optical waveguides are also suitable for transmitting high-energy, pulsed or continuous laser light in a wavelength range from 2.0 to 3.0 &mgr;m. These optical waveguides are also suitable for transmitting holmium laser light at 2.1 &mgr;m and Er laser light with a wavelength of 2.79 and 2.94 &mgr;m.

Glass for optical waveguides or the like

An physical-contact optical fiber connector for optical fibers has improved long-term stability. The fiber surface ends of the optical fibers are coated with a thin, absorption-free film made of very hard material, whereby the resistance to scoring is considerably increased. The thickness of the protective film is such that interfering reflection losses due to differences in the refraction indices are largely avoided. The hardness of the film is greater than that of the optical fiber material. Its optical thickness is also small compared to the operating wavelength. For optical fibers made of quartz glass, a protective film of Al.sub.2 O.sub.3 is used. Other oxides, nitrides borides, and carbides are also used. For optical fibers made of multicomponent glass or plastic, the protective film is made of an absorption-free material of greater hardness. The optical thickness of the protective film is between 1/1000 and 1/10 of the operating wavelength. The films are applied using ion-supported processes or ion-beam sputtering or the MicroPlasma process. Due to the small diameter of the rods, a large number can be placed into the coating system and coated at the same time. Thus physical-contact optical fiber connectors are obtained that have virtually unlimited service life and have extremely small insertion losses or connection losses.

Physical-contact optical fiber connector

An optical connection between optical fibers and an optical window exhibits improved long-term stability and improved measuring accuracy due to substantial transmission constancy. The surface of the optical window is coated with a thin, absorption-free coating of very hard material, thereby substantially improving the scratch resistance. The thickness of the protective coating is sized so that interfering reflection losses caused by differences in refraction indices may be avoided. The hardness of the protective coating is greater than that of the material of the optical window and its optical thickness is small in relation to the operating wavelength. The coating may be applied using ion-based, ion-beam dispersion, or microplasma methods.

Optical connection

Process of producing preforms for silica glass optical waveguides while

The optical element provides for the displacement of two end sections having slanted end faces. The slanted end faces have such an angle to the optical axis of the fiber, that the limit angle for total reflection is exceeded. The displacement remains substantially below the diameter of the fiber.

Growing community of inventors

Gross-Bieberau, Germany

Walter Heitmann