Buried-oxide silicon-on-insulator structures. II. Waveguide gratingcouplers

For pt.I, see ibid., vol.28, no.1, p.157-63 (1992). Grating couplers formed in buried-oxide silicon-on-insulator structures are analyzed using both a convergent Block wave approach and a simple approximate method. Strong interface reflections that occur during grating coupling can cause interference effects which result in variations in coupling efficiency and coupling length by an order of magnitude when varying grating period and film thickness parameters. Results indicate that proper coupler design is essential in order to obtain efficient coupling