Automatic Wavelength Locking Stabilization of Silicon Microring Modulator With 240Gb/s PAM4 Modulation

We present a method for automatic wavelength locking and stabilization of an ultra-high-speed silicon microring modulator. We developed a resonance wavelength locking control algorithm and a modulation efficiency optimization algorithm. By using low-frequency small-signal modulation to compute the modulation efficiency of difference resonance, the locking wavelength could be optimized. Up to 240 Gbits/s PAM4 modulation and 140 Gbits/s NRZ modulation were realized in the experiment with automatic wavelength locking. Long-term stabilization of wavelength locking was achieved using a self-immunity feedback algorithm, as verified by continuously testing the extinction ratio of the optical eye diagram for 12 hours.