  In high-performance RF photonic systems, the Electro-Optic (EO) modulators
play a critical role as a key component, requiring low SWaP-C and high
linearity. While traditional lithium niobate (LiNbO$_3$) Mach-Zehnder
Modulators (MZMs) have been extensively utilized due to their superior
linearity, silicon-based EO modulators have lagged behind in achieving
comparable performance. This paper presents an experimental demonstration of a
Ring Assisted Mach Zehnder Modulator (RAMZM) fabricated using a silicon
photonic foundry process, addressing the performance gap. The proposed RAMZM
modulator enables linearization in the optical domain and can be dynamically
reconfigured to linearize around user-specified center frequency and bias
conditions, even in the presence of process variations and thermal crosstalk.
An automatic reconfiguration algorithm, empowered by Digital-to-Analog
Converters (DACs), Analog-to-Digital Converters (ADCs), Trans-Impedance
Amplifiers (TIAs), and a digital configuration engine, is developed to achieve
linearization, resulting in a spurious-free dynamic range (SFDR) exceeding 113
dB.Hz$^{2/3}$. Furthermore, a biasing scheme is introduced for RAMZMs,
significantly enhancing the modulation slope efficiency, which in turn yields a
tone gain of over 13 dB compared to its standard operation. This reconfigurable
electro-optic modulator can be seamlessly integrated into integrated RF
photonic System-on-Chips (SoCs), leveraging the advantages of integration and
cost-effectiveness.
