We propose an all-optical switching element based on forward Bragg diffract
ion in a periodically corrugated semiconductor laser amplifier. The device
geometry is similar to that of an angled-grating distributed-feedback (alph
a-DFB) laser except that there is no reflective feedback. Light induced cha
nges in the refractive index cause the output to switch from a cross state
to a bar state with input power levels of only a few milliwatts.