High-efficiency and high-power InGaN-based laser diode at a wavelength of 405nm

We have developed InGaN-based laser diodes (LDs) with shorter wavelengths, including violet and ultraviolet, which are expected to contribute to a wide range of industrial applications. In this report, we present a high-power InGaN-based laser diode that achieves an optical output exceeding 12 W at a wavelength of 405nm, assembled in a TO-9 package designed for low thermal resistance. The LD features a single ridge-stripe structure fabricated in a p-type AlGaN cladding layer and is mounted p-side down on a submount. To reduce both optical and current densities, the LD employs a wide stripe width of 45 μm and a long cavity length of 1400 μm. The waveguide structure was optimized using metal-organic chemical vapor deposition (MOCVD) to reduce internal optical losses. Additionally, we designed a TO-9 package with low thermal resistance, incorporating an electrically insulating material with high thermal conductivity as the submount. These approaches effectively suppress the junction temperature by minimizing the thermal resistance of the LD. Consequently, we achieved an optical output exceeding 12 W at 25 °C and a maximum wall-plug efficiency (WPE) of 43.9% at 5.2 W operation. Furthermore, the LD exhibited remarkable high-temperature performance, maintaining a WPE above 40% even at 50 °C. To the best of our knowledge, these results represent the highest performance reported to date for InGaN-based LDs operating at this wavelength.