Abstract

Page-access optical memories offer strong potential for high-capacity, fast-transferrate, short-access-time systems due to the highly parallel and volumetric nature of the data storage mechanism. Examples of this type of memory include volume holography,¹ two-photon 3-D memory² and spectral hole burning holography,³ A common feature of these memories is that data is input by means of a spatial light modulator (SLM) and the output signal is imaged onto a detector array. A typical arrangement for a digital volume holographic data storage system is shown in Fig. 1. To achieve the capacity and transfer-rate goals for commercial systems, page sizes on the order of one million pixels are needed. Large page sizes impose stringent requirements on the optical system design, and any deviation from ideal imaging results in poor system performance. We describe a technique for data detection in a page-access optical memory extending the well- known method of sequence detection from digital communications to two dimensions. This technique, which we call Decision Feedback Viterbi Algorithm (DF-VA) Detection, improves the bit-errorrate (BER) performance.

© 1996 Optical Society of America