Abstract

Waveguide focusing grating couplers are being developed for application to optical data storage and for other applications where the advantages of light weight, monolithic construction, and ease of use with integrated optics are important. The polarization theory of these devices differs from the theory of conventional gratings because of the conversion of guided waves to radiated waves. We describe a simple theory based on induced dipoles that agrees well with experiment and that gives the designer insight into the process. The use of TM guided waves presents special difficulties. We discuss the design of waveguide focusing grating read-write heads for optical data storage applications, and show that it is possible, in principle, to achieve ideally mode-matched input and output, including intensity, phase, and polarization mode forms. Results of calculations of end-to-end performance will be presented. The experimental justification for the induced dipole theory will be described in a companion paper by Li et al.

© 1990 Optical Society of America