2018 Volume 41 Pages 77-84
In this paper, we present a high-power blue-violet (BV) indium gallium nitride (InGaN) laser diode (LD) and a high-brightness white light source using the InGaN LD. For realizing a high-power operation, we carry out two approaches. One is that the additional thick-optical-waveguide (TOW) is constructed on both sides of the active layer of the InGaN LD, which suppresses optical-loss and gives high wall plug efficiency (WPE). The other is that the LD chip on a submount is covered by another III-nitride ceramic submount, which reduces the thermal resistance. By using these novel optical-loss suppressing structure and double-heat-flow (DHF) packaging, the LD operates with a maximum output power of over 7.2 W at 25°C. In addition, a high luminous efficacy spot lighting system with a white light source using the InGaN LD is presented for lighting applications. By combining the high power InGaN LD, a phosphor and uniform illumination/high reflection optic elements, the system demonstrates the high light flux of 861 lumen and the high luminance efficacy of 51.3 lm/W.
