INGAASP (LAMBDA=1.3-MU-M) STRIP BURIED HETEROSTRUCTURE LASERS GROWN BY MOCVD

The characteristics of InGaAsP-InP index guided strip buried heterostructure lasers operating at 1.3-mu-m with a 1.1-mu-m guiding layer are described. The effective refractive index approximation is used to obtain the mode and waveguiding characteristics. These lasers are compared with buried heterostructure lasers having similar guiding layers under the active layer but terminated at the edge of the active layer. Experimentally, the lasers are grown by a two step atmospheric pressure MOCVD growth procedure, with an initial growth of the guiding, active, cladding, and cap layer by MOCVD, followed by etching into mesa stripes down to the guiding layer and recovering the etched regions with a 2-mu-m thick MOCVD grown InP: Fe current blocking layer. SBH lasers with 0.15-mu-m thick active layer strips, 5-mu-m wide, and guide layers varying from 0 to 0.7-mu-m have threshold currents increasing from 34 to 59 mA, and nearly constant differential external quantum efficiencies of 0.2 mW/mA. The threshold current increases more rapidly with temperature with guide layer thickness, with T0 decreasing from 70-degrees-C for lasers without a guide layer 54.3-degrees-C for lasers with 0.7-mu-m thick guide layers. Output powers up to 30 mW per facet have been obtained from 254-mu-m long lasers and were found to be insensitive to guide layer thickness.