4. Insertion/extraction filter

One of the generic applications of integrated optics concerns optical multiplexing and demultiplexing. The insertion/extraction filter is one of the basic building blocks for these new systems. Conventional approaches tend to be unable to meet the required performance in terms of selectivity and/or directivity. Although photonic crystal-based structures suffer from modest performance in terms of guidance, are they capable of offering compact and original solutions? In the following, we will attempt to provide some initial answers.