Low power and compact eight-channel reconfigurable optical add-drop multiplexers based on cascaded microring resonators

We report an eight-channel reconfigurable optical add-drop multiplexers (ROADMs) based on cascaded microring resonators with low tuning power and compact footprint. Microheaters are fabricated on the top of microring resonators, which can modulate microring resonators by the thermo-optic effect to achieve the reconfigurable functionality of the device. We demonstrate the reconfigurable add-drop multiplexing functionality for channel spacings of 100GHz and 50GHz, with the channel centre wavelengths aligned to International Telecommunication Unit (ITU) grid specifications. The crosstalk values for channel spacings of 100GHz and 50GHz are less than −22.5dB and −15.5dB, respectively. The average tuning power is about 4.854 mw/nm and the response speed is about 13.0 kHz.