Light modulator

US5508840A · kind A · utility

Assignee

• Ascom Tech AG · CH

Inventors

• Paul Vogel · Weingarten, DE
• Rainer Battig · Zürich, CH

Key dates

• Filing date: Nov 18, 1993
• Grant date: Apr 16, 1996
• Expiry date: Nov 18, 2013

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B26/06
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A light modulator useful for modulating a diverging light beam exiting from an optical fiber. In one embodiment, the modulator has a focusing lens and two flat partial mirrors. The lens collimates the light, one half of which respectively strikes each of the partial mirrors orthogonally. These mirrors reflect the light back onto itself causing, depending on the relationship between the wavelength of the incident light and the differences in path lengths, varying degrees of constructive or destructive interference. The difference in path length can be varied electrically if the partial mirrors are embodied as etched semiconductor foils which are controllably displaced in an electrostatic field set up between the foils and a substrate electrode.