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The rich legacy of quartz glass innovation
What is our legacy? Our legacy is built upon the innovative breakthroughs we have achieved in the past. And, is every partner who is influenced by us. Our impact and legacy transcend mere actions. We proudly refer to it as "industry transformation".
Take a look at our past breakthroughs in glass innovation, witness what we have accomplished, how we have achieved it, and the choices we have made to transform the industry. Our journey began in 1899 with the pioneering work of Heraeus chemist Richard Küch.
In 1899, Richard Küch, Heraeus physicist and chemist, invented a new type of oven based on oxyhydrogen blower at 2000°C that could melt rock crystal to produce bubble-free quartz glass of high purity for the first time. Since then, quartz glass, a new material with special properties, has been available industrially. This invention laid the foundation for our commitment to innovation and excellence in producing industrial-scale ultra pure quartz glass.
In 1912, Heraeus Quarzglas GmbH & Co. KG was founded in Hanau and is still the same legal entitity that is home to our business, Heraeus Comvance, today. Heraeus Quarzglas first produced laboratory equipment made of quartz glass for the chemical industry. This was followed by other applications, such as optics (optical quartz glass), temperature measurement (platinum resistance thermometer) and lamps (such as the original Hanau Höhensonne® sun lamp).
In 1949, Heraeus successfully produced fused silica tubes for the first time in an electric drawing furnace. This achievement marked a significant milestone in the development of high-quality fused silica products, opening up new possibilities for various industries, and specifically for the production of optical fibers.
In 1955, Heraeus successfully produced synthetic fused silica using special blowpipe technology. This breakthrough allowed for the creation of ultrapure quartz glass with a high degree of UV transparency. The resulting material Suprasil® found widespread application in aerospace engineering, where it was utilized for various optical components such as mirror prisms, lenses, and windows.
For today's telecom fiber, synthetic quartz glass is still the material of choice to maximize light propagation in a fiber, and achieve lowest rates of fiber breaks on the draw tower.
In addition to putting the first man on the moon on July 20, 1969, the legendary Apollo 11 mission also carried a laser reflector to Earth’s natural satellite. Still in operation today, the reflector is used to measure the exact distance between the Earth and the moon (about 384 000 km). It consists of an array of 100 triple prisms made of quartz glass from Heraeus.
The silica tubes provided by Heraeus played a crucial role in this process. This groundbreaking invention enabled the low loss in light transmission in optical fibers that opened the doors for application in data communication over practical distances on the order of kilometers. Heraeus has been supplying these tubes, and later also larger cylinders to AT&T and the subsequent corporations Lucent, OFS Fitel, and Furukawa still producing at the original AT&T site.
By initiating mass production of natural silica tubes, Heraeus was able to provide a reliable and consistent supply of this essential material to meet the growing demands of various industries. The use of advanced manufacturing techniques and strict quality control ensured that the produced tubes had exceptional purity and dimensional accuracy.
Buford plant started to support AT&T by local manufacturing of tubes to draw fibers 35 kilometers in length. Over time, the plant has advanced its manufacturing capabilities and now produces preforms that are drawn into fibers 7000 kilometers in length.
In the mid-1980, Heraeus developed a large-batch process to produce cylinders of synthetic fused silica. Gaseous raw materials that contain silica in their molecular structure are burnt so that quartz soot particles form and are deposited in an outside vapor deposition (OVD) process on a rotating bait rod. The soot accumulates and forms a porous body with a density that is less than 25 % of quartz glass. Because of its high surface, it is easy to infiltrate the porous soot body with functional gases. To eliminate light absorption by water in a fiber optic application, hydrogen is substituted with chlorine in a dehydration step before vitrifying the soot body. It can also be doped with Fluorine in order to achieve a lower density material to design optical fibers with radial refractive index profiles. Consecutively, the porous body is heated to be sintered or vitrified to a transparent quartz glas body.
After reunificaiton of east and west Germany in 1990, Heraeus built on the chemical infrastructure and available work force in Bitterfeld to build a plant for large-scale production of the highly pure synthetic fused silica, that grew in demand mostly for telecom fiber application. Due to its advantageous properties, the material is also used in fields such as optics, specialty fiber for industrial applications, semiconductor manufacturing, and laser technology.
Previously, the large cylinders from Bitterfeld were drawn into tubes in our Buford site, that were consecutively used to manufacture optical fibers by a Rod-in-Tube (RIT) process, introducing a core rod into the tube and drawing the assembly or preform into a fiber. The Rod-in-Cylinder (RIC®) process circumvents the step of tube draw, and enables very large preform/assemblies. This way, it not only enhances the performance of the fiber by reducing attenuation but also helps to lower production costs by increasing batch sizes.
In 2004, Quartz glass spheres prove Einstein's theory. Heraeus played a role in NASA's Gravity Probe B project by supplying quartz glass materials for the manufacturing of gyroscopes that helped to confirm Einstein's theory of relativity.
And in 2009, Heraeus provided quartz glass materials for the manufacturing of prisms and lenses for the Gaia astrometry satellite, a project of the European Space Agency (ESA).
Doping with Fluorine is also called down-doping as it lowers the refractive index compared to pure quartz glass. This way it has the opposite effect to the up-doping with Germanium that is used in the core of a fiber. Combining different levels of refractive indices in the radial profile of an optical fiber allows for advanced fiber designs to optimize light guiding properties. In ultra-low loss (ULL) fiber, for example, a clear silica core can be combined with down-doped cladding to improve light propagation in long-haul networks. In bend-optimized fibers, a down-doped trench can be introduced around the light-guiding core to improve the guiding properties and reduce light losses when the fiber is bent.
By large-scale implementation of down doping technology, Heraeus has driven innovation and advancement in the field of optical fibers, enabling the offering of more advanced and reliable solutions.
By increasing production capacity and the introduction of new technologies, Heraeus has been able to meet the growing demand for RIC® quartz glass cylinders. This expansion also reflects Heraeus's commitment to innovation and its capability to provide reliable and high-quality quartz glass products.
Heraeus developed a novel rare earth doped fused silica material to enable high-power fiber lasers in the multi-kilowatt range. This innovative material, incorporating rare earth elements into fused silica, allowed for efficient conversion and transmission of light, resulting in the production of high-power laser beams in fiber lasers. This technology advancement provided industries and research fields with higher power and more precise laser processing capabilities.
In 2020, the RIC® 230 pilot line generated cylinders capable of drawing 10,000 kilometer fibers per batch, significantly enhancing the efficiency and cost-effectiveness of cylinder production.
