This invention relates to an optical demultiplexor having a narrow band filter for separating a narrow band channel prior to utilizing one or more wide band filters for separating a plurality of channels into groups of channels. The groups of channels can then be further separated or demultiplexed by a plurality of narrow band filters. Advantageously, a plurality of closely spaced (i.e. 50 Ghz) channels can be separated using conventional dichroic filters.