Laser diodes are formed with an outcoupling grating between two separate
distributed Bragg reflectors. The devices have gain regions located
between the reflector gratings for pumping the active region. The
outcoupling grating couples light out of the waveguide normal to the
surface if the grating spacings are equal to an integer number of
wavelengths of the light within the cavity. If the gratings are not such
an integer number, the light is coupled out of the cavity off the normal.