Measurement of gain current relations for InGaN multiple quantum wells

Pulsed operation of in-plane laser diodes with InGaN multiple quantum well active regions was achieved. For uncoated chemically assisted ion beam etched facets, we obtained threshold current densities as low as 10.6 kA/cm(2). The external differential quantum efficiency dependence on bar length was used to determine the internal optical loss and internal quantum efficiency of these devices and to calculate the modal gain in the device as a function of the terminal current density. Values of facet reflection were determined by a self-consistent analysis. We have measured 90 cm(-1) of modal gain and estimate material gain exceeding 900 cm(-1), at 20 kA/cm(2). (C) 1998 American Institute of Physics. [S0003-6951(98)00652- 4].