You can freely build on How Corning Invented Modern Fiber Optic Cables
This patent expired in 1990. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Corning Glass Works
Patent granted
1973
Expired
1990
Forward citations
86
What this patent covers
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 is now free to use
All 0 claims of US 3711262 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
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.
Who is building on this today
Corning remains a dominant leader in the manufacturing of optical fiber. Companies like Prysmian Group and Sumitomo Electric have also built massive operations based on the fundamental principles of glass fiber drawing established here.
Products built on expired version of this technology
Undersea transoceanic internet cables
Fiber-to-the-home (FTTH) broadband connections
High-speed enterprise data center networking
How to cite this patent in your documentation
Corning Glass Works. US Patent 3711262. Method of producing optical waveguide fibers. Granted 1973, expired 1990. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.