Emerging Planar Waveguide Devices for WDM and Spectroscopy: Curved Waveguide Multiplexers and Interferometer Arrays

We review two emerging concepts in planar waveguide multiplexers and spectrometers. The first concept is a planar waveguide demultiplexer with the wavelength dispersive properties provided by a diffraction grating formed in the sidewall of a curved Si waveguide. The phase errors are minimized using an apodized design with a chirped grating, yielding a crosstalk below -30 dB. The device has 15 channels with a wavelength spacing of 25 nm, thus a …