Four-stage Mach-Zehnder-type tunable optical dispersion compensator with single-knob control

We present a concept for colorless tunable optical dispersion compensators consisting of a series arrangement of generalized interferometers and adjustable lenses. The designs require only one control knob to adjust the dispersion, making the control simple and low power. We demonstrate a four-stage all-two-arm version in silica waveguides that achieves 460-ps/nm tuning range on a 100-GHz grid for 40-Gb/s signals.