Improved methods for generating dynamic computer generated holograms for realising adaptive optical cross connects

Diffractive optical elements (DOE) designed by computer, i.e. computer generated holograms (CGH), offer precise control over optical wavefronts that is difficult to attain using classical optical elements and that can be of significant benefit to optical interconnection systems. Typically a CGH is implemented in a fixed medium via standard methods of micro- fabrication which may either be used directly or as a master for volume manufacture via process of replication. The computer time required to design the CGH is then not a significant issue and it is standard practice to employ computationally expensive algorithms such as simulated annealing (SA) to optimize the design. However, advances in spatial light modulator technology now offer the prospect of programmable computer generated holograms that have particularly promising application in reconfigurable interconnections systems e.g. holographic beam steering switches.