Broadband Mach-Zehnder Switch for Photonic Networks on Chip

In this paper, we propose a broadband silicon Mach-Zehnder switch (MZS) for wavelength division multiplexing applications on photonic networks on chip. The proposed reconfigurable switch is based on a single-stage three-waveguide interferometric configuration in which the phase shift is achieved via a p-i-n diode. The device is analyzed by the coupled-mode theory and by the finite-difference beam propagation method. The proposed configuration leads to a considerable increase in the bandwidth with respect to the conventional MZS. For example, the two-waveguide MZS with a gap g = 0.30 mu m between the two coupled waveguides exhibits bandwidth Delta lambda = 60 nm, crosstalk CT = -15dB, and insertion loss IL = 1.1 dB. Conversely, a bandwidth Delta lambda = 115 nm is achieved for the three-waveguide configuration to parity of the other parameters.