Diffusion-limited etching for compact, low-loss semiconductor integrated optics

It is shown that diffusion-limited wet chemical etching can be used to fabricated single-mode GaAs/AlGaAs rib waveguides suitable for compact circular waveguide bends (300- mu m radius). The waveguides exhibit lower propagation losses (1-4 dB/cm at 1.52- mu m wavelength) than previously reported guides fabricated for compact bend applications by dry etching. To study the radius dependence of waveguide bend loss, a set of nested 90 degrees circular bends was fabricated simultaneously on a single chip.<
>