Design And Fabrication Of Even-Orders-Missing Encoding Binary Phase Grating

Even-Orders-Missing (EOM) encoding binary phase grating is a kind of special optical beam splitters which all even diffracted orders are suppressed, spot arrays as the result is even number with many advantages such as high efficiency and array uniformity, enable to meet the information of a single input transform into multiple output, in some industry and the military fields such as optical communication, optical interconnection, optical computing and storage, multiple imaging has important applications.This dissertation researches the implementation method of EOM. Desigh and optimize the grating by using self-compiled packages based on simulated annealing (SA) and downhill algorithm. Adopting electron beam direct writing (EBDW) and reactive ion etching (RIE) to fabricate the grating on the silica. The fan-out is 16×16, period is 1.2mm, actual efficiency is 83.19%, the maximum relative deviation of spot uniformity is 8.64%, and the reconstruction error is 4%. Application of simulated annealing (SA) and downhill algorithm to optimize the result, and it should be taken to avoid the result that is only partially optimal value which influence the quality of optimization. In the EOM case, where the zeroth order is not one of the beams, the phase error has no effect in the reconstruction error; it only reduces the efficiency by a multiplicative factor sin~2(σ/2). Graphic accuracy error is one of the main reasons to cause the degradation of arrays uniformity. There are also some factors such as radio frequency (RF) power and other parameters will impact on etching rate and the surface shape of groove in the RIE process.