S-bend loss in disorder-delineated GaAs heterostructure laser waveguides with native and blue shifted active regions

The routing ability of waveguide S-bend structures patterned by SiO2 impurity induced layer disordering of a single GaAs quantum well graded barrier laser structure is investigated. For a raised-cosine bend with 100 μm offset guides, the measured transition length for 3 dB loss was less than 300 μm for near single mode guides of 1 μm width. In addition, vacancy-induced disordering of the native quantum well region is investigated and is shown to increase the band gap to a point where the material is low loss for radiation generated by the laser. The 3 dB length for these blue shifted cores actually decreased to about 230 μm, a fact attributed to reduced mode conversion.