Photonic crystal waveguide based dispersion compensators

We have investigated the dispersion properties of photonic crystal waveguide resonators. A passive InGaAsP/InP slab waveguide structure was used for the fabrication of the samples. The PhC waveguide resonators were defined by the omission of several rows of holes along the Gamma K or Gamma M direction of a triangular photonic crystal lattice. In addition, mirrors with a thickness of 1 to 4 rows of holes were inserted into the waveguide. An optimized dry etch process was used to etch the patterns, to a depth of 3.5 mu m through the waveguide layer. The group delay of the PhC devices was measured using the phase shift technique. The signal of a tunable laser was modulated at 3 GHz using a LiNbO3 Mach-Zehnder modulator and detected with a high-frequency lightwave receiver. A phase sensitive detection with a network analyer measured the phase shift of the transmitted signal, which is proportional to the group delay. Close to the center of the resonances, the chromatic dispersion reaches values of -250 ps/mn and 250 ps/mn. This corresponds to the chromatic dispersion of 15 km standard fiber.