One-dimensional to two-dimensional channel formatting with micro-optics for wavelength division multiplexing networks

We present a method of interfacing a conventional wavelength multiplexing and demultiplexing device with a two-dimensional (2D) array of surface-active elements, such as micro-electromechanical system devices or photodetectors. We use diffractive optical elements to transform wavelength division multiplexed signals spread along a line into a 2-D array. We applied this technique to build a device that is compatible with an arrayed-waveguide grating. The theoretical insertion loss predicted by combining beam propagation and rigorous coupled-wave analysis is 2.75 dB. However, the experimental loss is 10dB. The difference is due to the poor quality of the diffraction gratings. Nevertheless, the formatting operation was performed successfully.