Fabrication and Characterization of High Power InGaN Blue-Violet Lasers with an Array Structure

InGaN/GaN multi-quantum-well-structure
laser diodes with an array structure are successfully fabricated on
sapphire substrates. The laser diode consists of four emitter stripes
which share common electrodes on one laser chip. An 800-μm-long cavity
is formed by cleaving the substrate along the orientation using laser scriber. The threshold current and voltage of the
laser array diode are 2A and 10.5V, respectively. A light output peak
power of 12W under pulsed current injection at room temperature is
achieved. We simulate the electric properties of GaN based laser diode in
a co-planar structure and the results show that minimizing the difference
of distances between the different ridges and the n-electrode and
increasing the electrical conductivity of the n-type GaN are two effective
ways to improve the uniformity of carrier distribution in emitter stripes.
Two pairs of emitters on a chip are arranged to be located near the two
n-electrode pads on the left and right sides, and the four stripe emitters
can laser together. The laser diode shows two sharp peaks of light output
at 408 and 409nm above the threshold current. The full widths at half
maximum for the parallel and perpendicular far field patterns are
8° and 32°, respectively.