A microring modulator array coupled to a common bus waveguide can be used to construct low power, compact and flexible wavelength-division-multiplexing (WDM) transmitters. However, due to extremely small working bandwidths of the rings, it is challenging to find the right resonant wavelength setting and locking the resonance to an external laser. In the paper, we propose a novel technique enabling simultaneous wavelength locking of a microring modulator array with a single monitor, together with automatically optimizing the wavelength setting. We experimentally demonstrate locking three rings over a temperature range >40 °C at 3x20 Gb/s on-off-keying (OOK) modulation and ~3x75 Gb/s discrete multi-tone (DMT) modulation.

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