Free-space grating demultiplexer for densely-spaced, subnanometer wavelength-routed optical networks

We report on the diffraction-limited performance of a free-space aberration corrected concave grating demultiplexer. The fibre-to-fibre loss was less than 9 dB and channel isolation better than 25 dB for channel spacing of 0.4 nm, in the wavelength range 24 nm around 1.5 /spl mu/m. This device has applications in wavelength routing crossconnects and in optical spectrum analysers.