Vol. 41, Issue 3, pp. 669-678 (2011)

Abstract

In this paper, we calculate three effective refractive indexes for cascaded silicon-on-insulator (SOI) nonlinear directional coupler. For each effective refractive index, the coupling length L_C, core-to-distance-ratio K and switching threshold power P_{i, m} are calculated, respectively. However, there are some fabrication errors, which are ΔW, ΔH, ΔK in the height of Si layer and width of Si layer and error of core-to-distance-ratio. We have analyzed the influence of power transmission efficiency T_{i, j} and relative transmission efficiency error Δ_{i, j} caused by the change of ΔW, ΔH, ΔK. Furthermore, we find the tolerance range of ΔW, ΔH, ΔK for T_{i, j} and Δ_{i, j} in couplers a, b, c. The other four input pulses with different powers are switched to four different ports. Although output pulses show some little compression and loss, the value of η is very small and output pulse waveforms are not affected seriously. The basic switching function has been realized, so this design is proved to be effective.