Improved output beam quality using new-type flared semiconductor laser amplifiers

Summary form only given. A reliable, coherent, and high-power laser source is important for many applications. High-power semiconductor lasers therefore draw much attention due to their compactness, low cost, and other advantages. Recently flared semiconductor laser amplifiers have demonstrated the highest output power with extremely good spatial coherence. The fluctuation of beam intensity and the variation of the carrier concentration mutually influences one another, leading to the filamentation. However, what is the first cause of the spatial variation remains unexplained. We assert that the fluctuation mainly results from the reflection of the light from the boundary of the waveguide.