CHARACTERISTICS OF COHERENT 2-DIMENSIONAL GRATING SURFACE EMITTING DIODE-LASER ARRAYS DURING CW OPERATION

Recent progress in the development of monolithic two-dimensional coherent grating surface emitting (GSE) laser arrays is presented. Such GSE arrays have operated continuously to more than 3 W / surface and pulsed to more than 30 W / surface. They have obtained CW threshold current densities of under 140 A / cm2 with CW differential quantum efficiencies of 20-46% per surface. Linewidths in the 40-100 MHz range have been obtained with output powers of 100-300 mW per surface. The arrays typically consist of 10-30 mutually injection coupled gain sections with 10 laterally coupled ridge-guided lasers in each gain section. A single GaInAs strained-layer quantum well with a graded index separate confinement heterostructure geometry allows junction down mounting with light emission through the transparent GaAs substrate. A surface relief grating is used for feedback and outcoupling.