The application of the selective intermixing in selected area (SISA) technique to the fabrication of photonic devices in GaAs/AlGaAs structures

We demonstrate the fabrication of multiple wavelength lasers, and multi-channel wavelength division multiplexers using the one-step 'selective intermixing in selected area' quantum well intermixing technique in GaAs/AlGaAs structures. This technique is based on impurity-free vacancy diffusion and enables one to control the degree of intermixing across a wafer. Lasers with the bandgaps tuned to five different positions have been fabricated on a single chip. These lasers showed only small variations in transparency current, internal quantum efficiency and internal propagation loss, which indicates that the quality of the material remains good after being intermixed. Four-channel wavelength demultiplexers or waveguide photodetectors have also been fabricated. Photocurrent and spontaneous emission spectra from individual diodes showed the shift of the absorption edge by different degrees due to the selective degree of quantum well intermixing. The results obtained also demonstrate the use of this technique in the fabrication of broad wavelength emission superluminescent diodes.