Analysis of detuned second-order grating output couplers with an integrated superlattice reflector

Analysis is presented of second-order gratings at wavelengths detuned from the reflection bandwidth. These gratings have applications, for example, as surface-emitting output couplers in monolithic integrated master oscillator power amplifier (M-MOPA) configurations. The grating output couplers have reflectivities below 10/sup -4/ at an emission wavelength of 874 nm when the Bragg condition of the second-order grating occurs at 904 nm. When used in conjunction with a superlattice reflector integrated into the substrate, the surface emission can exceed 85% of the radiation incident on a 250 mu m long grating. Consequently, these gratings can act as nearly ideal output couplers in a M-MOPA without introducing undesirable feedback to the amplifier or master oscillator.<>