Abstract

Although many papers have recently been published on computer generated holograms (CGHs) or diffractive optics for optical interconnects, most research has concentrated on connections that involve relatively small angles. Small angle connections require relatively low CGH spatial frequencies and can be implemented efficiently with many CGH design and encoding methods. Large angle connections, however, are needed to implement long distance interconnects with a high connection density. For example, an optically interconnected multichip module system is currently under development. Connection lengths of up to 40 mm and angles as large as 27° are needed. For such large deflection angles, the CGH spatial frequencies are so large that with conventional encoding methods only two phase levels can be employed, and the resulting diffraction efficiency through two successive holograms is limited to a maximum value of 16%. Therefore we developed a new encoding method that allowed us to increase the number of phase levels in the CGH, thereby increasing the diffraction efficiency.

© 1992 Optical Society of America