Silicon mode-(de)multiplexer for a hybrid multiplexing system to achieve ultrahigh capacity photonic networks-on-chip with a single-wavelength-carrier light

Hybrid multiplexing technology combining polarization multiplexing and mode multiplexing is presented to expand the capacity of photonic networks-on-chip by 2N times with a multimode optical waveguide which supports 2N guided-modes. Only one laser diode is needed for such a multiplexing system. A novel mode-(de)multiplexer with low excess-loss and low crosstalk is proposed by utilizing a structure with cascaded asymmetrical directional couplers. A 1×4 mode-(de)multiplexer is designed as an example. It is possible to achieve more channels (e.g., 2N=16) with two orthogonal polarizations. When an array of high-speed optical modulators (e.g., 70Gbps) is integrated, the total capacity of an on-chip photonic link can be over 1Tbps with a single-wavelength-carrier light.