Competitive light wavelength division multiplexing element based on tunable interference wedged structures

Interference Wedged Structure (IWS) is an optical element with useful properties for optical metrology, spectral analysis and optical communications. We have introduced in the paper a new perspective element of this type – Composite Tunable Interference Wedged Structure (CTIWS). The CTIWS is list-like sequence of superimposed wedged layers each with reflecting surfaces. For conveniently chosen apex angles and thicknesses of the layers, the CTIWS can assure high spectral selectivity to 0.01nm within a spectral range of 10 nm and more at smooth tunability by simple sliding of the structure along the wedge arm (a few cm). We have developed simple physical description of the IWS and CTIWS by adapting Fabry-Perot theory. We show that for the most important practical cases the results are similar to the obtained by more complex exact analytical description. The theoretical predictions are confirmed by experimental results. On the base of IWS and CTIWS combined in a suitable architecture, we have introduced and studied a new lossless Wavelength Division Multiplexing (WDM) element with independent tuning of each output/input. We considered the WDM implementation for the case of fiber optical systems used in optical communications.