Browse Prior Art Database

Optical Switch

IP.com Disclosure Number: IPCOM000062445D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Elsner, G: AUTHOR [+4]

Abstract

An optical bistable switch element with internal amplification ("optical transistor") uses a control light beam 3 to vary the index of refraction in a non-linear medium and thus to switch the optical signal beam 2 between transmission and total internal reflection at the boundary of the non-linear medium 1. The figure shows an example of the optical transistor integrated in a micro-optical device. The non-linear material, such as GaAs or InSb for infrared radiation, has a tapered end (angle R) such that the horizontal optical signal beam 2 impinges at an angle slightly less than that for total internal reflection and exists as beam T. (The angle of total internal reflection may also be influenced by suitably doping the boundary surface.

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Optical Switch

An optical bistable switch element with internal amplification ("optical transistor") uses a control light beam 3 to vary the index of refraction in a non-linear medium and thus to switch the optical signal beam 2 between transmission and total internal reflection at the boundary of the non-linear medium 1. The figure shows an example of the optical transistor integrated in a micro-optical device. The non-linear material, such as GaAs or InSb for infrared radiation, has a tapered end (angle R) such that the horizontal optical signal beam 2 impinges at an angle slightly less than that for total internal reflection and exists as beam T. (The angle of total internal reflection may also be influenced by suitably doping the boundary surface.) However, in the presence of the control beam 3 (whose intensity is such that it induces the desired index change together with the signal beam), the angle of total internal reflection is lowered below the angle of incidence, and the beams are reflected in the direction R. For optimum switching performance, the light is polarized in the plane of incidence. The non-linear medium is integrated in a semiconductor device comprising a heterojunction laser 4, generating the signal beam 2, and an adjacent modulator laser 5, generating the control beam. A Bragg reflection zone 7 is arranged between the laser diodes 4, 5 for feedback purposes. A single laser diode with two parallel electric excitation circuits (one for each...