All-optical de-aggregation of 16QAM to PAM-2/PAM-4 by phase-sensitive amplification in silicon hybrid slot waveguides

We present an all-optical de-aggregation scheme that converts a single 16QAM signal into two PAM-2 and two PAM-4 channels by dual-pump phase-sensitive amplification (PSA) in a silicon-CNT/PDMS hybrid slot waveguide. The waveguide design provides a phase mismatch bandwidth from 1350 to 1850 nm and achieves a high nonlinearity of 1.308×10⁸W^-1m^-1 at 1550 nm. We divide the 16QAM constellation into outer-ring S1 and inner-ring S2 subsets, then de-aggregate each by PSA. At a 4.2 mW pump power, the PSA achieves approximately 30 dB of gain. Numerical simulations and analyses of constellations, output signal-to-noise ratio (SNR), and error-vector magnitude (EVM) show that, as the input SNR varies from 8 to 32 dB, the two PAM-2 channels improve EVM from 31% to 5%, while the two PAM-4 channels improve EVM from 31% to 7%. These results demonstrate the scheme's potential for flexible format conversion and de-aggregation in dynamic opticaletworks.