Large scale modulator arrays for beam steering and optical modulator applications

Abstract

Multi-quantum well (MQW) spatial light modulators (SLM) have a significant potential to change the paradigm in a number of applications where a high rate of modulation of a coherent optical source is of interest. Such applications include optical correlators where spatial light modulators are required as input and as filter plane devices .l In this case the effectiveness of the correlator in accomplishing signal processing is directly related to the speed that the spatial light modulators can be operated. In beam steering applications the SLMs are used as a grating (either an intensity grating or a phase grating) to create constructive and destructive interference effects that result in direction of the light in specific directions.' In optical memory systems SLMs can be used as input/output devices for data entry and retrieval.' They are also of interest as the active elements in optical beam routing architectures for data switching or routing?Past reports have described the MQW SLM and have illustrated results where these SLMs were used in specific applications. The MQW SLM was described by Worchesky et a14 and has been subsequently used in a number of demonstrations reported in referenceslS2 and others, . Work by other groups are of interest here, notably Miller's pape? describing modulator results, and more recently Bowman et a1 has described an optically addressable SLM based on resonant cavity devices and references other work related to the MQW SLMs.6In this paper we briefly review the SLM concept, the elements that are used to produce an array, the approach to processing the optical devices and the integration concepts that have so far been employed. We provide an example of a modulator design based on a beam steering application and then we review application results where MQW SLMs were employed in optical correlators for optical processing, optical beam steering, and input/output devices for optical memory systems.Previous reports"'*' have given details of BAE SYSTEMS' SLM performance in a number of applications including optical correlation, signal processing, laser printing, and data conversion systems. Recent efforts have focussed on process improvements and on development of devices for new applications, such as beam steering, 3D LIDAR, and A/D converters.Preliminary electrical results from new 1x512 devices on have demonstrated full electrical operability for this very small pixel pitch (13 pm with 0.8 pm interpixel spacing). With this achievement, further reductions in pixel pitch can be envisioned; this is desirable to increase the maximum beamsteering -' Correspondence: E-Mail: mareie.weiler(d1mco.com; Telephone: 603-885-6029; FAX: 603-885-6036; Address: P. 0. Box 868 NHQ 6-1517, Nashua,

A Driver Circuit of Spatial Light Modulator

“…SLMs development set the new request driver circuit at a higher speed, lower power consumption and higher precision. Previously, some reports have described a multi-chip module array CMOS driving and four pieces of digital to analog converter (DAC) [3][4][5][6][7][8][9] .This solution allows high frame rate and high power consumption. In addition, the clock signal pathways in motherboard need synchronous drive and 4 DAC chip.…”