Inverse-designed ultra-compact high efficiency and low crosstalk optical interconnect based on waveguide crossing and wavelength demultiplexer

In this paper, we use the inverse design method to design an optical interconnection system composed of wavelength demultiplexer and the same direction waveguide crossing on silicon-on-insulator (SOI) platform. A 2.4 μm × 3.6 μm wavelength demultiplexer with an input wavelength of 1.3–1.6 μm is designed. When the target wavelength of the device is 1.4 μm, the insertion loss of the output port is − 0.93 dB, and there is − 18.4 dB crosstalk, in TE0 mode. The insertion loss of the target wavelength of 1.6 μm in TE0 mode is − 0.88 dB, and the crosstalk is − 19.1 dB. Then, we designed a same direction waveguide crossing, the footprint is only 2.4 μm × 3.6 μm, the insertion loss of the wavelength 1.4 μm and 1.6 μm in TE0 mode is − 0.99 dB and − 1 dB, and the crosstalk is − 12.14 dB and − 14.34 dB, respectively. Finally, an optical interconnect structure composed of two devices is used, which can become the most basic component of the optical interconnect network. In TE0 mode, the insertion loss of the output wavelength of 1.4 μm at the output port is − 1.3 dB, and the crosstalk is − 29.36 dB. The insertion loss of the output wavelength of 1.6 μm is − 1.39 dB, and the crosstalk is − 38.99 dB.

1 × 2 plasmonic wavelength demultiplexer using rectangular MIM waveguide

A 1 × 2 plasmonic demultiplexer with a rectangular metal-insulator-metal (MIM) waveguide comprising one input port and two output ports has been proposed. The proposed demultiplexer is based on the principle of interference of surface plasmon polariton waves. By placing the output port at the designed position along the rectangular MIM waveguide, the desired wavelength can be extracted from the mixture of the wavelengths. Results were simulated using finite element method (FEM) technique and plot of field and its intensity were obtained for both the wavelengths. The results agree with the proposed theory. Power transmission of more than 80% at the desired port with a suppression of more than 90% at the undesired port is obtained for both the wavelengths. A low crosstalk of less than −11.06 dB with a low insertion loss of less than 14.32 dB are measured. It is shown that the wavelength selectivity of the plasmonic demultiplexer is further dependent on the width of the MIM waveguide as well as the materials chosen. The design can be further extended to a 1×N demultiplexer by appropriate selection of position of the output ports.