Low-threshold index-guided 1.5 mu m long-wavelength vertical-cavity surface-emitting laser with high efficiency

A significantly improved InP-based vertical-cavity surface-emitting laser w ith record device performance is demonstrated. Utilizing a twofold epitaxia l growth process, self-adjusted lateral current confinement and index guidi ng are accomplished by means of a buried InGa(Al)As tunnel junction. Front and back mirrors are realized by 35 epitaxial InGaAlAs/InAlAs layer pairs a nd a 1.5 MgF2/a-Si layer pair, respectively. At room temperature and under continuous wave condition, lasers with small aperture diameters of only 13 mu m exhibit record output powers of 1.6 mW with quantum efficiencies aroun d 25%. For these devices, threshold current and voltage are as low as 4 mA and 1.2 V, respectively, because of low series resistances around 70 Omega. (C) 2000 American Institute of Physics. [S0003-6951(00)05016-6].