RECONFIGURABLE MEMS WAVEGUIDE BASED ON PHOTONIC CRYSTAL MEMBRANE

摘要

We present our design and fabrication of a semiconductor based photonic bandgap(PBG) nano-membrane device with MEMS features. This device could be used as a basicbuilding block for a reconfigurable optoelectronic integrated circuit that can bereprogrammed for different functionalities. We combine a PBG platform with a MEMSfeature to build such a reconfigurable device. The device has a top PBG membrane layerstructure composed of hexagon holes in a triangular lattice. Below that, a separate suspendedbridge layer can insert a line of posts into the photonic crystal holes to create a defect line.This MEMS feature can generate/cancel a section of the waveguide in the PBG platform, orit can change the dispersion of the waveguide. Therefore, the same structure can be used asdifferent types of devices such as switches, modulators, time delay lines, etc. This device isfabricated on GaAs/Alx1GaAs/Alx2GaAs/GaAs-substrate epi-layers grown by MBE. We havedeveloped the fabrication technique for such a device using e-beam lithography, inductivelycoupled plasma (ICP) reactive ion etching, and multiple steps of regular photolithographyand selective wet chemical etching. The fabricated PBG membranes are 60 nm to 300 nmthick, with a thin wall between the holes of ~120 nm. A line of mushroom shaped MEMSposts are inserted into the ~1 μm PBG holes. We are fine tuning each of these processingsteps toward the fabrication of a workable device.