Asymmetric directional coupler working in multiple wavebands

The invention relates to a multiband working asymmetric directional coupler, which comprises a first access waveguide, a coupling access waveguide and a bent waveguide which are connected in sequence, and a first bus waveguide, a coupling bus waveguide and a second bus waveguide which are arranged side by side and are connected in sequence, the width of the coupling access waveguide in the coupling area is gradually reduced along with increase of the distance, the width of the coupling bus waveguide is gradually increased along with increase of the distance, and a gap exists between the coupling access waveguide and the coupling bus waveguide. According to the asymmetric directional coupler, the length of the coupling area of the asymmetric directional coupler is optimized, so that the working bandwidth of the asymmetric directional coupler is expanded to multiple wave bands, the working bandwidth is greatly improved, and the on-chip single channel capacity is improved. 一种多波段工作的非对称定向耦合器，包括：依次相连的第一接入波导、耦合接入波导和