Observation of pulse compression in photonic crystal coupled cavity waveguides

We demonstrate the compression of picosecond pulses using the large group velocity dispersion available from planar photonic crystal (PhC) coupled cavity waveguides (CCWs). A maximum pulsewidth reduction of 40%, from 1.91 to 1.17 ps, is achieved, in transmission through an 8-μm-long planar PhC waveguide; The equivalent dispersion value is >10⁶ times larger than that available from standard single-mode fiber, at the pulse center wavelength of 1536 nm. The device performance is analyzed with the aid of both two-dimensional (2-D) eigenmode expansion and 2-D finite-difference time-domain (FDTD) models. The models included the material dispersion of the GaAs/AlGaAs heterostructure, into which the PhCs are etched, and show remarkable agreement with experiment.