DESIGN OF ACHROMATIC HOLOGRAPHIC GRATING COUPLERS FOR SUBSTRATE AND BACKPLANE OPTICAL INTERCONNECTS

Holographic backplane optical interconnects for multi-board three-dime nsional packaging of electronic modules have demonstrated certain inte resting features. However, the effects of laser diode wavelength shift s, caused by variations in environmental temperatures and by bias fluc tuations can cause undesirable coupling alignment problems, including shifting of the coupling angle and optical spot positions. These chrom atic problems are particularly serious in terms of coupling from backp lane to board-level waveguide interconnect networks. To solve these pr oblems, an achromatization technique for holographic backplane coupler s under substrate beam propagation geometry is presented in this paper .