Amplitude/Polarization Shift Keying Based and Logic Gate in Polarization Dependent C-Rich SiC Ring Waveguide

The TE/TM-mode spectral-separated C-rich SiC ring waveguide is employed to demonstrate polarization-dependent amplitude/polarization shift keying (ASK/PolSK) “AND” logic gate. The plasma-enhanced chemical vapor deposition-grown C-rich SiC film exhibits a nonstoichiometric SiC nano-cluster phase structure with a C/Si atomic ratio of 1.28, which provides an efficient nonlinearity of γ = 4.3 × 10
²
W
⁻¹
m
⁻¹
and n
₂
= 2.44 × 10
⁻¹²
cm
²
/W to demonstrate the “AND” gating between incoming ASK and PolSK data streams. By carefully designing the polarization preference of the ring waveguide structure, the TE/TM-mode-dependent transmission combs are spectrally separated because of the high birefringence of the waveguide optically triggered by the incoming pulsed stream. This type of a polarization dependent spectral notch can be utilized to perform the polarization-dependent all-optical AND gating, which was done in the current study by inserting a dual-format modulated pump and a continuous-wave probe into a ring waveguide. Output of the probe can be cross-wavelength modulated to provide the exact “AND” gating between the ASK and PolSK streams only when the pump is set to the ON state and the polarization of the pump is parallel to the corresponding notch of the ring waveguide throughput. This type of C-rich SiC ASK/PolSK AND logic gate is fully compatible with silicon-based complementary metal-oxide-semiconductor (CMOS) technology, which also has the advantages of low power consumption and enables polarization engineering for future photonic data logics.