Browse Prior Art Database

Push Button Switches for Optical Fibers

IP.com Disclosure Number: IPCOM000080534D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Kaser, K: AUTHOR [+4]

Abstract

Light guided in an optical fiber with core and cladding can be interrupted by a push button. In a housing, a depressed button causes a significant change in the light transmission of the dielectric waveguide.

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Push Button Switches for Optical Fibers

Light guided in an optical fiber with core and cladding can be interrupted by a push button. In a housing, a depressed button causes a significant change in the light transmission of the dielectric waveguide.

Embodiment A comprises a fiber with a core of index n1 and a cladding of n2 which is partly replaced by a liquid environment of the same index n4 = n2, such that light propagates undisturbed along the fiber. The depressed key displaces some liquid and provides instead, matter of another refractive index n3 which is larger than n1. The loss of total internal reflection at the interface of the higher refractive material leads to an effective interruption of the light path, due to diffraction and subsequent absorption at the housing walls. Resilient force to reset the key is exerted by a compressed gas bubble.

Embodiment B uses an extension of the incoming glass fibre which is built of an elastic plastic cladding with a liquid core. The depressed key pinches off the liquid core, thus interrupting light transmission by disturbing the wave propagation properties. The same optical fiber part can also be used for input and output, e.g., by providing a mirror at the rear side of a light pipe end section with a solid cladding.

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