Spectral demultiplexer with a plate waveguide

An optical demultiplexer with a fused quartz plate 300 μ thick was developed. Energy from fiber waveguides with a core diameter ≤ 300 μ and an aperture 0.4 was coupled into the demultiplexer without energy losses. The device was capable of demultiplexing five optical carriers in the 0.7–0.9 μ range for a linewidth ≤ 3 nm at spectral intervals of 50 nm. The crosstalk level was less than – 20 dB in respect of the optical power, and the losses in each channel were 3 dB. Promising results were obtained when three-dimensional optical devices were replaced with planar integrated elements based on plate waveguides.