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Integrated Optical Logic Using Photochromic Material

IP.com Disclosure Number: IPCOM000082967D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Freeman, LB: AUTHOR [+3]

Abstract

Photochromic (PC) logic elements can be used to perform logic functions and can be integrated on a suitable substrate, to give it monolithic light channelling and optical logic capability. Two advantages to incorporating a PC "light switch"into an integrated circuit (IC), are that it eliminates (1) the conversion, in optical logic circuits, from electrical energy to light energy and back to electrical energy; and (2) the interface loss between the input signal and the optical device.

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Integrated Optical Logic Using Photochromic Material

Photochromic (PC) logic elements can be used to perform logic functions and can be integrated on a suitable substrate, to give it monolithic light channelling and optical logic capability. Two advantages to incorporating a PC "light switch"into an integrated circuit (IC), are that it eliminates (1) the conversion, in optical logic circuits, from electrical energy to light energy and back to electrical energy; and (2) the interface loss between the input signal and the optical device.

Commercially available photochromic materials exhibit a wide variation in intensity transmission, when they are exposed by a suitable electromagnetic energy source. This energy source can be ordinary visible light, ultraviolet or infrared. The variation for certain photochromic materials is between 0.1g and 80% during the devices active and inactive states, respectively. This unique property leads these materials to be used as a light switch.

The following describe the operation of an inverter logic function when its input is low, when its output and input are high, and when its output is low:

1. Fig. 1 shows a reference light source 4 with its input light source 6 off. There is maximum transmittance through the photochromic light switch 8, possibly 80%. The light passes through light channels 10. The device is nonactive.

2. When the reference light source 4 is on, transmittance is reduced to a predetermined intermediate level. The refere...