HIGH-COUPLING-EFFICIENT 1.3-MU-M LASER-DIODES WITH GOOD TEMPERATURE CHARACTERISTICS

We have proposed uniformly beam-expanded structures based on the advan ced concept for realizing high coupling efficiency and good temperatur e characteristics. Beam expansion (optical confinement reduction) by n arrowing the core layer width as well as a carrier confinement are str ongly enhanced by adopting a larger bandgap InGaAsP for MQW barriers a nd separate confinement heterostructure layers. These laser diodes (LD 's) were fabricated by the conventional buried heterostructure laser p rocess, which is very important in reducing the cost. Our results have proven the effectiveness of our proposition. The LD's with high coupl ing efficiency (-3.2 dB) and good temperature characteristics have bee n achieved even using the simple approach of reducing optical confinem ent. The threshold currents at 25 and 85 degrees C are 9.3 and 39.4 mA , respectively. The slope efficiency at 25 degrees C is 0.39 W/A and s till high (0.26 W/A) even at 85 degrees C.