Automatic tuning of silicon photonics microring filter array for hitless reconfigurable add-drop

Given the escalation of demand for high-speed data interconnection, both between users and datacenters, high-capacity optical networks need a boost in capacity, flexibility, and efficiency. To stand up for those problems, the network reconfigurability is a key feature in a saturated and power hungry network operating scenario. In this paper, a reconfigurable optical node, using a commercial integrated photonics foundry, was conceived, fabricated, and tested. A novel application of automatic control of complex optical circuits involving locking and tuning of microring resonators is presented. The technique exploits a channel labeling strategy to identify a single optical channel amid a dense wavelength division multiplexing comb. The fabricated filter array provided add-drop ports with hitless channel reconfiguration and telecom graded specifications as 20 dB of in-band isolation, 40 GHz of channel bandwidth in a microring filter with 1 THz of free spectral range.