Junction-current-confinement planar light-emitting diodes and optical coupling into large-core diameter fibers using lenses

High-radiance AlGaAs-GaAs double-heterostructure light-emitting diodes utilizing junction current confinement are described. Diode resistance and junction ideality factor are investigated as a function of emission diameters from 10 to 75 µm. Near-field intensity profiles indicate tight current confinement over the full range of emission diameters. Rise-time measurements are consistent with a simple carrier lifetime model for >25-µm emission diameters. An effective radiative-recombination constant, B = 1.5(±0.5) × 10-¹⁰cm³/s is deduced from the rise-time data and model. Peak wavelength and spectral width data are discussed in terms of junction current density and temperature. With decreasing emission diameter, the optical coupling efficiencies into 100- and 200-µm core diam high-numerical-aperture fibers increased from 10 to 25 percent and 25 to 50 percent, respectivley, using spherical glass lenses.