Micro-ring wavelength selective switch device based on contra-DC

This paper presents, to our knowledge, a novel micro-ring wavelength selective switch device based on a contra-directional coupler (contra-DC), which utilizes the transparent window formed by the contra-DC to select the single resonant wavelength of the micro-ring resonator, avoiding the limitation of free spectral range and realizing the function of wavelength selection/switching. The desired wavelength switching function is achieved by changing the crystal state of the <i>G</i> <i>e</i> ₂ <i>S</i> <i>b</i> ₂ <i>T</i> <i>e</i> ₅ (GST) loaded on the micro-ring resonator. When the device is in the on state, the desired wavelength signal is selectively output from the drop port of the bus waveguide; when the device is in the off state, light is output from the through port. By modifying the GST crystal state, selective routing of light can be achieved, which can be used in optical interconnection networks. The simulation is performed using a 3D finite-difference method. The wavelength selection device achieves a 3 dB bandwidthof 1.6 nm with a side lobe suppression ratio of 20 dB at a length of 230 µm; the switching device achieves the extinction ratio of about 14.7 dB and a side lobe suppression ratio of 18.2 dB between the on/off states.