Buried heterostructure complex-coupled distributed feedback 1.55 mu m lasers fabricated using dry etching processes and quaternary layer overgrowth

An attractive process for fabricating buried heterostructure complex-couple d distributed feedback (BH-CC-DFB) lasers emitting at 1.55 mu m has been de veloped. It combines low damage chemically assisted ion beam etching (CAIBE ) for grating definition, subsequent overgrowth of a quaternary GaInAsP lay er (lambda(PL) = 1.22 mu m) by low-pressure metalorganic vapor phase epitax y, reactive ion etching for mesa definition and semi-insulating InP:Fe regr owth by hydride vapor phase epitaxy. CAIBE improves grating uniformity, GaI nAsP layer overgrowth increases gain coupling and semi-insulating regrowth facilitates lateral mode confinement and thermal dissipation. The as-cleave d BH-CC-DFB lasers fabricated with the above combination show a statistical single mode yield of 87% and a very high side-mode suppression ratio up to 55 dB. A -3 dB bandwidth of 10 GHz is also demonstrated. (C) 1999 American Vacuum Society. [S0734-211X(99)02406-3].