Propagation of optical pulses in photonic crystal waveguides

The dispersion properties of planar photonic crystal (PhC) coupled cavity waveguides are investigated. Both pulse broadening and compression have been demonstrated by propagating various chirped sub-picosecond pulses through the waveguides. The PhC waveguide exhibits large positive group-velocity dispersion (GVD), which is opposed to the negative GVD in a single-mode fibre (SMF). A maximum pulse width reduction of 40%, from 1.91 ps to 1.17 ps, is achieved, after transmission through an 8 μm long planar PhC waveguide. The equivalent dispersion value is >10⁶ times larger than that available from standard single-mode fibre at the pulse centre wavelength of 1536 nm.