# Using Heat to Move Tiny Mirrors for Controlling Light Beams > A system that uses tiny, heat-powered mechanical arms to move mirrors into the path of light beams, effectively acting as a switch for fiber optic networks. - **Patent:** US RE39833 - **Original title:** USRE39833E1 - Thermally actuated spectroscopic optical switch - **Owner:** Southwest Research Institute SwRI - **Granted:** 2007 - **Status:** Public domain (expired) - **Times cited:** 1 - **Field:** telecommunications, semiconductors, mechanical ## What it does This patent describes an optical switch built on a small substrate, similar to a computer chip. It uses 'cantilevered arms'—small beams anchored at one end—that hold a tiny mirror at the other. When heat or electricity is applied, the arm bends due to differences in how its materials expand, pushing the mirror into the path of a light beam coming from an optical fiber. This allows the system to physically redirect light from one fiber to another, acting like a railroad switch for data signals. ## What it does NOT cover - Does not cover optical switches that use magnetic fields or electrostatic force to move mirrors. - Does not cover systems where the light path is redirected by changing the refractive index of a material rather than physically moving a mirror. - Does not cover switches that do not use a cantilevered arm structure with specific thermal expansion properties. ## The clever bit The innovation lies in using a 'bimetallic' or differential thermal expansion effect within a micro-scale cantilever to achieve precise mechanical movement without needing complex motors or external actuators. ## Real-world examples 1. Fiber optic network routing equipment 2. Spectroscopic analysis instruments 3. Micro-Electro-Mechanical Systems (MEMS) optical switches ## Why it matters Managing light signals in fiber optic networks is difficult because you cannot simply 'pause' light like an electrical current. This technology provides a way to route data signals physically, which is essential for high-speed telecommunications and spectroscopy equipment where light needs to be directed to different sensors or receptors without losing signal quality. ## Frequently asked questions ### What does Using Heat to Move Tiny Mirrors for Controlling Light Beams cover? A system that uses tiny, heat-powered mechanical arms to move mirrors into the path of light beams, effectively acting as a switch for fiber optic networks. ### Who owns patent US RE39833? Southwest Research Institute SwRI owns this patent, granted in 2007. ### When does this patent expire? This patent is expected to expire on September 11, 2027, when the invention enters the public domain. ### What is patent US RE39833 cited by? This patent has been cited by 1 later patents that build on its ideas. ### What problem does this patent solve? Managing light signals in fiber optic networks is difficult because you cannot simply 'pause' light like an electrical current. This technology provides a way to route data signals physically, which is essential for high-speed telecommunications and spectroscopy equipment where light needs to be directed to different sensors or receptors without losing signal quality. ### What does this patent NOT cover? Does not cover optical switches that use magnetic fields or electrostatic force to move mirrors. **Full plain-English explainer:** https://patentbrief.org/patent/us/RE39833/tpa-variants **Original patent:** https://patents.google.com/patent/USRE39833 --- _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: - [A Sealed, Stamped Metal Assembly for Guiding Light in Fiber Optics](https://patentbrief.org/patent/us/10761280/hermetic-optical-subassembly) — This patent describes a tiny, sealed optical assembly that uses precisely shaped metal parts and mirrors to guide light signals between a fiber optic cable and an electronic light-emitting or light-sensing device without needing lenses between the main mirrors. - [A Stamped Mirror to Connect Optical Fibers to Tiny Light Chips](https://patentbrief.org/patent/us/12422629/optical-connection-of-optical-fibers-to-grating-couplers) — This patent describes a method to precisely connect a standard optical fiber to a tiny light-based computer chip (a photonic integrated circuit) using a specially shaped, stamped mirror that redirects and reshapes the light. - [How to Embed Tiny Optical Components Directly into Circuit Boards](https://patentbrief.org/patent/us/RE50510/gemini-bard) — A design for embedding light-emitting components and light-guiding paths directly into the layers of a circuit board to make devices smaller and more efficient. - [How Chips Get Both Light and Electricity on a Special Glass Base](https://patentbrief.org/patent/us/12326604/integrated-circuit-packages-having-electrical-and-optical-connectivity-and-metho) — This patent describes a way to build computer chip packages using a special glass base that can carry both electrical signals and light signals, making chips faster and more efficient. - [Attaching Flexible Circuits with Light Sensors to a Chip](https://patentbrief.org/patent/us/9055681/method-for-attaching-a-flexible-structure-to-a-device-and-a-device-having-a-flex) — This patent describes a method and device for attaching a bendable circuit, which includes light-sensing or light-emitting components, onto a main chip, allowing light to pass through a hole in the chip to reach the flexible part.