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Use of Field-Induced Interference of Coherent Optical Transients for Optical Data Processing and Logic

IP.com Disclosure Number: IPCOM000111171D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 4 page(s) / 112K

Publishing Venue

IBM

Related People

Jefferson, CM: AUTHOR [+3]

Abstract

Disclosed is a method for performing fast optical data processing and logic operations using photon echoes produced by irradiating an inhomogeneously broadened absorption line in a material with a sequence of optical pulses. These pulses must be applied within the phase coherence time of the material which normally requires operation at reduced temperatures. This method shows that various logical operations can be performed by using an external field to induce interference between stimulated photon echo pulse sequences which are simultaneously recalled by a single reference pulse.

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Use of Field-Induced Interference of Coherent Optical Transients
for Optical Data Processing and Logic

      Disclosed is a method for performing fast optical data
processing and logic operations using photon echoes produced by
irradiating an inhomogeneously broadened absorption line in a
material with a sequence of optical pulses.  These pulses must be
applied within the phase coherence time of the material which
normally requires operation at reduced temperatures.  This method
shows that various logical operations can be performed by using an
external field to induce interference between stimulated photon echo
pulse sequences which are simultaneously recalled by a single
reference pulse.

      In order to use the interference of coherent light waves for
data processing, a reproducible adjustment of their timing and their
relative optical phases is needed.  While it is straightforward to
modulate the amplitude and the phase of a coherent light wave to
obtain sequences of coherent light pulses, it is difficult to adjust
the timing and the relative optical phases of two independently
generated optical pulse trains.  The proposed technique overcomes
this difficulty in that two pulse trains, D sub 1 and D sub 2 and
their phases can be stored independently from each other in the same
sample volume, when an inhomogeneous external electric field E sub 1
or E sub 2 respectively is applied during the writing process.
Recall of the data pulse trains can be made at the electric field
values at which they were stored.  If the field strengths are chosen
such that at an intermediate value both data strings can be recalled
simultaneously by one single reference pulse, their timing is correct
and they are automatically in phase.  The resulting interference of
the data pulses can be used for optical data processing and optical
logic.

      Two different data strings D sub 1 and D sub 2 containing the
bits 1,0,0,1 and 1,0,1,0 are stored at the electric field strength
values E sub 1 and E sub 2 with zero mutual optical phase difference.
The recall of the two data pulse sequences as stimulated photon
echoes is depicted in Fig. 1.  When a field of strength E sub 1 (or E
sub 2) is applied, the data sequences D sub 1 (or D sub 2) can be
recalled separately (Figs. 1a and 1b).  At the intermediate value E
sub 12 = (E sub 1 + E sub 2)/2 both data strings D sub 1 and D sub 2
are simultaneously recalled by the...