Waveguide structure effect for the C- And L-band of optical directional full couplers

The waveguide structure effect for the C- and L-band of optical directional full couplers weighted by Hamming function are numerically investigated by Hamming weighting function. Under global search algorithm, the structure parameters of coupling waveguide are obtained by beam propagation method. In the condition of -35 dB crosstalk, it is found that the coupler lengths for C-(1.53-1.565 μm), L- (1.57-1.61 μm), and C+L-band are 3.0, 2.6, and 3.6 mm, respectively. Obviously, such couplers have an advantage over conventional couplers for the demand of the suitable coupler length.