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A Cryogenic Circuit Gate Utilizing An Injection Laser

IP.com Disclosure Number: IPCOM000096747D
Original Publication Date: 1963-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Nethercot, AH: AUTHOR

Abstract

Information entered into or removed from a cryogenic computer should dissipate a minimum amount of heat. Laser beams can be employed to communicate with a cryogenic computer with a rate of heat dissipation which is small compared with even a single coaxial conductor.

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A Cryogenic Circuit Gate Utilizing An Injection Laser

Information entered into or removed from a cryogenic computer should dissipate a minimum amount of heat. Laser beams can be employed to communicate with a cryogenic computer with a rate of heat dissipation which is small compared with even a single coaxial conductor.

Where information is desired to be entered into the computer, as in 1, a heat pulse, resulting from the stimulated emission of the injection laser L, causes the input cryotron C to become resistive for the duration of the pulse. On the basis of the velocity of the heat pulse in the input cryotron which substantially approximates the electron velocity, a switching time of 10/-11/ seconds is forecast for a 10 micron thick gate. The speed is at least as fast as 10-9 seconds if the phonon velocity determines the heat flow. The turnoff time for the cryotron C is hastened because the heat continues to spread as the gate temperature falls. Also, the heat of the electrons is shared with the lattice which causes the temperature to drop.

The cryotron gate C normally has high reflectivity at low temperatures which would tend to make inefficient coupling between injection laser L and cryotron C. This inefficiency is overcome by using the cryotron C as one reflector of a Fabry-Perot laser cavity. The other reflector is S on laser L. Thus, multiple reflections take place between diode and cryotron gate C. Such multiple reflection permits energy to be absorbed by...