1.55 mu m single mode lasers with complex coupled distributed feedback gratings fabricated by focused ion beam implantation

Complex coupled GaInAsP/InP distributed feedback lasers were developed based on maskless focused ion beam lithography. By combining implantation enhanced wet chemical etching and implantation induced thermal quantum well intermixing a refractive index grating was defined self-aligned to a gain grating forming a complex coupled grating lateral to a ridge waveguide. The devices show single mode emission at wavelengths around 1.55 mu m with linewidths 90%) over a large tuning range (88 nm) was achieved. (C) 1999 American Institute of Physics. {[}S0003-6951(99)00137-0].