A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. To enable a radial mixing within the shear zone in addition to the tangential mixing with the lowest possible time and energy input, starting from this method, cylindrical sections of the blank are adjacent to the shear zone on both sides, the first cylindrical section having a first central axis and the second cylindrical section having a second central axis, the first central axis and the second central axis being temporarily non-coaxial with each other.

A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. The displacement of the shear zone along the longitudinal axis of the blank is superimposed by a simultaneous oscillating motion of the shear zone along the longitudinal axis of the blank. The first end of the blank is rotated at a first rotational speed and the second end of the blank is rotated at a second rotational speed. An oscillating motion of the shear zone is generated by periodically varying the first and/or second rotational speed.

A method for manufacturing an SiO.sub.2—TiO.sub.2 based glass upon a target by a direct method, includes a first process of preheating the target and a second process of growing an SiO.sub.2—TiO.sub.2 based glass ingot to a predetermined length upon the target which has been preheated, wherein the target is heated in the first process such that, in the second process, the temperature of growing surface of the glass ingot is maintained at or above a predetermined lower limit temperature.

Layered glass structures and fabrication methods are described. The methods include depositing soot on a dense glass substrate to form a composite structure and sintering the composite structure to form a layered glass structure. The dense glass substrate may be derived from an optical fiber preform that has been modified to include a planar surface. The composite structure may include one or more soot layers. The layered glass structure may be formed by combining multiple composite structures to form a stack, followed by sintering and fusing the stack. The layered glass structure may further be heated to softening and drawn to control linear dimensions. The layered glass structure or drawn layered glass structure may be configured as a planar waveguide.

Laser waveguides, methods and systems for forming a laser waveguide are provided. The waveguide includes an inner cladding layer surrounding a central axis and a glass core surrounding and located outside of the inner cladding layer. The glass core includes a laser-active material. The waveguide includes an outer cladding layer surrounding and located outside of the glass core. The inner cladding, outer cladding and/or core may surround a hollow central channel or bore and may be annular in shape.

A known method for homogenizing glass includes the following steps: providing a cylindrical blank composed of the glass, having a cylindrical outer surface which extends between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and moving the shear zone along the longitudinal axis of the blank. To reduce the risk of cracks and fractures during homogenizing, it is proposed that a thermal radiation dissipator is used that at least partially surrounds the shear zone, the lateral dimension of which in the direction of the longitudinal axis of the blank is greater than the shear zone and smaller than the length of the blank, the thermal radiation dissipator being moved synchronously with the shear zone along the longitudinal axis of the blank.

Laser waveguides, methods and systems for forming a laser waveguide are provided. The waveguide includes an inner cladding layer surrounding a central axis and a glass core surrounding and located outside of the inner cladding layer. The glass core includes a laser-active material. The waveguide includes an outer cladding layer surrounding and located outside of the glass core. The inner cladding, outer cladding and/or core may surround a hollow central channel or bore and may be annular in shape.

A synthetic quartz glass substrate having a controlled hydrogen molecule concentration is prepared by (a) hot shaping a synthetic quartz glass ingot into a glass block, (b) slicing the glass block into a glass plate, (c) annealing the glass plate at 500-1,250 C. for 15-60 hours, (d) hydrogen doping treatment of the glass plate in a hydrogen gas atmosphere at 300-450 C. for 20-40 hours, and (e) dehydrogenation treatment of the glass plate at 200-400 C. for 5-10 hours.

One aspect relates to a method for producing an optical blank from synthetic quartz glass by vitrifying and shaping a porous, cylindrical SiO.sub.2 soot body having a longitudinal axis, in a heating zone including a melt mold with bottom plate. The SiO.sub.2 soot body vitrified in the heating zone at a vitrification temperature so as to form a full cylindrical, completely vitrified, transparent quartz glass body. Subsequently, the vitrified quartz glass body is shaped by softening in the melt mold at a softening temperature so as to form a viscous quartz glass mass which partly fills the volume of the melt mold, and cooling the quartz glass mass and removal from the melt mold so as to form the optical blank. During shaping in the melt mold, the full cylindrical quartz glass body is brought into contact by way of controlled supply with a centering means of the bottom plate.

A known method for homogenizing glass includes the following steps: providing a cylindrical blank composed of the glass, having a cylindrical outer surface which extends between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and moving the shear zone along the longitudinal axis of the blank. To reduce the risk of cracks and fractures during homogenizing, it is proposed that a thermal radiation dissipator is used that at least partially surrounds the shear zone, the lateral dimension of which in the direction of the longitudinal axis of the blank is greater than the shear zone and smaller than the length of the blank, the thermal radiation dissipator being moved synchronously with the shear zone along the longitudinal axis of the blank.