  Silicon microring modulator (Si-MRM) has become one of the most promising
compact modulators to meet the increasing capacity requirements of the next
generation optical interconnection. The limited electro-optical (E-O)
bandwidth, low modulation efficiency, and inherent modulation nonlinearity are
the major factors that limit the Si-MRM modulation speed. To address these
issues, we comprehensively optimize the Si-MRM from the device to the
modulation and the signal processing. Large modulation bandwidth over 67GHz is
achieved in our newly fabricated Si-MRM. Additionally, the laser wavelength and
bias voltage of Si-MRM are optimized to significantly improve the modulation
performance. Finally, we comprehensively study the theoretical model of
modulation nonlinearity in Si-MRM, especially transient nonlinearity. A
bidirectional gate recurrent unit (Bi-GRU) neural network with minor
modification is applied to compensate for the nonlinear impairments. With all
these efforts, we experimentally demonstrate a 302 Gbps Si-MRM-based O-band
optical interconnection and achieve 300 Gbps transmission over a 1-km standard
single-mode fiber using the discrete multitone modulation format with bit and
power loading (BPL-DMT).
