Maskless fabrication of submicrometer nonharmonic relief gratings for single-frequency DFB semiconductor lasers by three-beam holographic method

摘要

Abstract: Three-beam maskless holographic method for fabricating submicron nonharmonic relief structures with phase shift $pi@, which are capable of providing stable single-frequency oscillation at Bragg wavelength in semiconductor DFB lasers, is developed. To demonstrate the effectivity of this method the biharmonic structure with period d $APEQ 0.5 $mu@m and quasisinusoidally modulated amplitude, possessing the phase shift $pi@, is fabricated on n-InP surface in the process of liquid-phase laser photoelectrochemical etching.!6