A high-brightness ridge-waveguide (RW) continuous-wave (CW) laser diode emitting 2.2 W of light at a 1060 nm wavelength into a circular beam profile has been demonstrated by researchers from Technical University of Berlin (Berlin, Germany), King Abdul-Aziz-University (Jeddah, Saudi Arabia), and Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (Berlin, Germany): the beam quality (m2) was between 1.4 and 1.9 across the whole operating-current range for the RW laser. A broad-area (BA) version of the laser delivered 4.2 W of multimode output. Cavity lengths were a few millimeters; both lasers had a divergence angle of less than 10°. The low divergence, low astigmatism, and circular beam shape of these lasers make them suitable for simple and low-cost fiber-coupling.
With these results, the so-called high-brightness vertical broad-area edge-emitting (HiBBEE) laser structure, which was recently patented by two of the researchers, was experimentally demonstrated for the first time. The HiBBEE structure includes a waveguide consisting of four indium gallium arsenide (InGaAs) quantum wells separated by gallium arsenide phosphide (GaAsP) barriers. Cladding, contact layers, and electrodes complete the configuration. Although the geometry allows for several vertical laser modes, their contrasting confinement factors and optical losses lead to mode selection. Potential uses for these lasers include medical laser therapy, frequency conversion, and spectroscopy. Reference: Md. Jarez Miah et al., Opt. Express, 24, 26, 30514–30522 (2016); http://dx.doi.org/10.1364/OE.24.030514.
