Results of a theoretical and experimental investigation into the variation of coupling efficiency with coupling angle are presented for various beam focusing conditions for an integrated optical grating coupler. This investigation shows that the acceptance angle of the grating coupler can be broadened, within a relatively large range and with a relatively small loss of coupling efficiency, by focusing the incident laser beam.
© 1990 Optical Society of America
Lifeng Li and Mool C. Gupta, "Effects of beam focusing on the efficiency of planar waveguide grating couplers," Appl. Opt. 29, 5320-5325 (1990)