GaAs-based microelectromechanical waveguide switch

We describe a 1×2 waveguide switch which is also a cantilever, fabricated in GaAs-based materials. This switch can be cascaded into 1×N structure. The layout and layer cross section of the waveguide are shown schematically. Actuation is accomplished by electrostatic means, by application of bias between the movable waveguide and static electrodes. This results in 4 μm motion of the cantilevered waveguide in the plane of the wafer. The waveguide consists of 4 μm thick GaAs/AlGaAs layer, while the release layer is composed of 2 μm of Al_0.7Ga_0.3As. Metal contacts are deposited on a planar substrate prior to waveguide definition. Then 3 μm wide waveguide is defined by RIBE. Photoresist is defined on the areas to be protected against release and sacrificial layer is removed by a HF-based wet etch. After photoresist removal, devices are sublimation dried. Fabrication issues, such as choice of materials, release chemistries and their implications are further discussed. Also, further details of device performance are given