Analysis of Wavelength Multiplexing Approaches for High Power Multi-Emitter Semiconductor Laser Modules

The paper analyses wavelength-multiplexing approaches to scale the output power of multi-emitter fibre-coupled laser diode modules beyond the values achievable by using spatial and polarization multiplexing only, which represent current state-of-the-art. Both dichroic mirror and grating based configurations are considered. The latter is particularly promising when used in combination with a new generation of Distributed Bragg Reflector (DBR) chips, which have proved to be much more stable than the Fabry-Perot (FP) layout typically used for high-power devices. A model to optimize the grating performance has been developed and a preliminary design of a grating-assisted multiplexing layout is reported.