Variable integrated optical logic element

US4262992A · kind A · utility

Assignee

• The United States of America, as represented by the Director, National Security Agency · US

Inventor

• John W. Berthold · Salem, US

Key dates

• Filing date: Apr 18, 1979
• Grant date: Apr 21, 1981
• Expiry date: Apr 18, 1999

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F1/3137
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A variable integrated optical logic element, formed on a substrate of electro-optic material, capable of being controlled to perform the six basic logic operations AND, OR, EXCLUSIVE OR, NAND, NOR and EXCLUSIVE NOR. The optical logic element comprises a plurality of single-mode optical waveguides which form a group of parallel and series equal-arm interferometers. The optical logic element operates on the principle of constructive and destructive interference between light beams. Voltage means are provided for varying the index of refraction of certain of the optical waveguides, to produce relative phase differences in the light energy propagating therein. By inducing phase shifts in the light energy propagating in appropriate waveguides, each of the six basic logic operations can be performed. Also disclosed is an electrically passive, phase-sensitive optical coupler, which is used for switching light energy between waveguides. The switching operation performed by the phase-sensitive coupler is a function of the presence or absence of and the relative phase differences between the light energy input to the coupler.