Active InGaAsP/InP Photonic Bandgap Waveguides for Wavelength-Selective Switching

An active optical switch based on the InGaAsP/InP photonic bandgap (PBG) buried waveguide is proposed. The device, which is made of a periodic grating patterned on a buried waveguide, exploits the localization of states in the PBG induced by the presence of an active defect. The wavelength of the localized state can be shifted by properly choosing the defect length and the injected current density in order to achieve a wavelength-selective switching behavior. Proprietary codes based on the bidirectional beam propagation method and the method of lines (BBPM-MoL) were used for the simulations of the optical device taking into account the rate equations to model the interaction between the optical signal and the active medium. Design curves are provided and parameterized to give general design rules. From the numerical analysis, the proposed device exhibits good theoretical performances in terms of crosstalk (CT < -2 dB), modulation depth (MD > 0.9) response time (in the subnanosecond range), and maximum size (< 170 μm)