This scanning electron microscopy image details a portion of the photonic crystal structure used for wavelength demutiplexing. A periodic array of holes with a 220 nanometer radius is etched through the top silicon layer of a silicon-on-insulator wafer.
August 8, 2006 Georgia Tech researchers have found a way to shrink all the sensing power of sophisticated biosensors — such as sensors that can detect trace amounts of a chemical in a water supply or a substance in your blood — onto a single microchip. In compact communication, signal processing and sensing optics technologies, multiple wavelengths of light are combined as a space-saving measure as they carry information. The wavelengths must then be separated again when they reach their destinations. Wavelengths used for these sophisticated applications have very high spectral resolution, meaning the distance between wavelengths is very small. The device that sorts out these crowded wavelengths is called a wavelength-demultiplexer (WD).