# How Corning Invented Modern Fiber Optic Cables > A 1970 method for creating glass fibers that carry light over long distances by layering glass inside a tube and drawing it into a thin, solid strand. - **Patent:** US 3711262 - **Original title:** Method of producing optical waveguide fibers - **Owner:** Corning Glass Works - **Granted:** 1973 - **Status:** Public domain (expired) - **Times cited:** 86 - **Field:** telecommunications, materials, mechanical ## What it does The patent describes a process for manufacturing optical waveguides by depositing a thin film of glass with a specific refractive index onto the inner surface of a glass tube. This tube, which has a different refractive index, acts as the cladding. The combined structure is then heated and drawn, causing the tube to collapse inward and form a solid, thin fiber. This creates a core of high-purity glass surrounded by a cladding layer, which is the essential structure required to keep light trapped inside the fiber via total internal reflection. ## What it does NOT cover - Does not cover the chemical vapor deposition processes (like MCVD) that later became the industry standard for mass production. - Does not cover the use of plastic or polymer-based optical fibers. - Does not cover the specific electronic hardware used to transmit or receive the light signals. - Does not cover fiber optic cables that do not use a core-cladding structure with differing refractive indices. ## The clever bit The innovation was the realization that you could create a solid fiber by collapsing a tube, ensuring the core and cladding were perfectly aligned and fused during the drawing process. ## Real-world examples 1. Undersea transoceanic internet cables 2. Fiber-to-the-home (FTTH) broadband connections 3. High-speed enterprise data center networking ## Why it matters This patent represents the birth of the modern telecommunications backbone. By demonstrating a viable way to produce low-loss glass fibers, it enabled the transition from copper wires to light-based data transmission, which now carries the vast majority of global internet traffic. ## Frequently asked questions ### What does How Corning Invented Modern Fiber Optic Cables cover? A 1970 method for creating glass fibers that carry light over long distances by layering glass inside a tube and drawing it into a thin, solid strand. ### Who owns patent US 3711262? Corning Glass Works owns this patent, granted in 1973. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 3711262 cited by? This patent has been cited by 86 later patents that build on its ideas. ### What problem does this patent solve? This patent represents the birth of the modern telecommunications backbone. By demonstrating a viable way to produce low-loss glass fibers, it enabled the transition from copper wires to light-based data transmission, which now carries the vast majority of global internet traffic. ### What does this patent NOT cover? Does not cover the chemical vapor deposition processes (like MCVD) that later became the industry standard for mass production. **Full plain-English explainer:** https://patentbrief.org/patent/us/3711262/optical-fiber-waveguide **Original patent:** https://patents.google.com/patent/US3711262 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How Glass Fibers Are Spun for Insulation](https://patentbrief.org/patent/us/2133235/fiberglass-glass-wool-slayter) — A 1933 invention by Games Slayter that describes the process of melting glass and blasting it into fine, flexible fibers to create insulation. - [How the Float Glass Process Makes Perfectly Flat Window Panes](https://patentbrief.org/patent/us/2911759/float-glass-pilkington) — This 1954 patent describes the float glass process, a method for creating high-quality, perfectly flat glass by floating molten glass on a bath of liquid metal. - [How Chemically Strengthened Glass Works](https://patentbrief.org/patent/us/3778335/gorilla-glass-chemically-strengthened) — A 1971 Corning patent describing a specific chemical recipe for glass that can be made incredibly tough by swapping small atoms in its surface for larger ones. - [How the First Laser Was Invented](https://patentbrief.org/patent/us/2929922/laser-maser) — The foundational 1960 patent by Schawlow and Townes that describes how to amplify light waves to create a laser, moving beyond microwave technology. - [Making Strong, Porous PTFE: The Gore-Tex Process](https://patentbrief.org/patent/us/3953566/gore-tex-expanded-ptfe) — This patent describes a specific process for rapidly stretching a highly crystalline form of PTFE plastic to create a strong, porous material with a unique internal structure, forming the basis for products like Gore-Tex.