CHARACTERIZATION OF THE ARRAY MODES OF HIGH-POWER GAIN-GUIDED GAAS SINGLE-QUANTUM-WELL LASER ARRAYS

The characteristics of gain-guided GaAs single-quantum-well laser arra ys, using proton bombardment to confine the current dow to 11 stripes on 9-mu m centers, are described, The longitudinal-mode spectrum, the spectrally resolved far-field, and the near-field of this laser array were studied experimentally up to three times threshold current, The l aser arrays are found to emit at similar to 10 longitudinal modes corr esponding to the Fabry-Perot modes of the laser, The longitudinal spec trum is current dependent, Near threshold current, the spectrum consis ts of a number of longitudinal modes where only the fundamental mode o f the array lases, At larger current, each of the longitudinal modes i s broadened and the spectrum of each longitudinal mode consists of man y individual emission lines of the array modes, For each longitudinal mode, the lowest order array mode emits at the longest wavelength, and the highest order array mode emits at the shortest wavelength, The wa velength separation between neighboring array modes increases with inc reasing mode order. Fourteen array modes are found to emit simultaneou sly at three times threshold current, The experimental results are in good agreement with direct array-mode analysis based on the finite-dif ference method.