Dynamic Holographic Interconnections Using Photorefractive Crystals

Abstract

Dynamic global interconnections between processors in massively parallel computers are a highly desirable feature. Their implementation would greatly increase performance because large bandwidth interprocessor communication links may be reconfigured to match problem geometries. Global hardwiring of interconnects for large processor arrays is cumbersome, and present systems use rather tedious packet routing virtual interconnects. This report presents a novel design concept for a dynamic optical interconnect which would create a holographic interconnect between any two (or more) processors upon request. Each processor has a detector and a light source. A hologram may then be written into a nonlinear crystal which will diffract modulated light from a source at one processor to detectors at any other processors which desire that communication link. Writing is a two step process using a phase conjugate mirror and requiring the light sources of the involved processors to be mutually coherent. Preliminary analysis of this system along with an experimental proof of concept is discussed.

An energy‐efficient free‐space optical interconnection for clock distribution

“…In a simple case, if we assume that the optical path difference 61 between successive clock pulses is equal to 2 L and the time difference between these cycles is equal to T , then ( 9 ) where c is the velocity of light in free space and n , is the refractive index of the medium enclosed by the mirrors. Equations (7) and (9) provide the basis for the design of the mirror system. The parameter n can be determined from the case when a multiply reflected ray no longer has significant energy to deliver, and hence is neglected in our calculations.…”

Dynamic holographic interconnects using static holograms

“…14). Hence, is icT=' (7) where T1cT 5 the diffraction efficiency of the crosstalk grating, is is the diffraction efficiency of the signal grating, and CR is the SLM contrast ratio. Experimental verification of this dependence is shown in Fig.…”

Acousto-optic photonic crossbar switch Part I: design

“…14 Several approaches to utilizing deflectors for interconnections have been advanced, including approaches based on periodic magnetic domains, 15 acousto-optic deflectors, 16 -20 and holography. [21][22][23] Acousto-optic technology is the most highly developed and offers the highest reconfiguration speed.…”