50-Wavelength Channel-by-Channel Tunable Optical Dispersion Compensator Using a Combination of AWG and Bulk Grating

We propose a novel optical configuration for a multichannel tunable optical dispersion compensator (TODC) with channel-by-channel operation across the entire
$L$
-band. The TODC consists of a cyclic frequency arrayed-waveguide grating whose free spectral range coincides with the channel spacing, a bulk grating, and a liquid crystal on silicon. We achieved channel-by-channel compensation over 50 channels with a maximum chromatic dispersion of
$\pm$
800 ps/nm.