Multichannel demultiplexer for optical communication lines

A demultiplexer was developed on the basis of a waveguide plane made of fused quartz and intended for use in communication lines composed of fiber waveguides with a core diameter 50 μ. The dimensions of the demultiplexer were 19.8 × 20 × 0.014 mm. Aberrations of a spherical mirror were studied and partly suppressed so that the demultiplexer could be used in separation of 18 spectral channels in the wavelength λ = 0.74–1.7 μ. The total losses in the central channels of the demultiplexer were 3 dB and the cross-talk losses were 20 dB. It was found that the demultiplexer could be operated effectively using radiation sources with a spectral band not wider than 20 nm. The problem of the change in the aperture of the radiation emerging from the demultiplexer was analyzed.