Enhanced Nonlinear Refractive Index of C-Rich SiC Waveguides Via Annealing for PRZ-OOK Data Transmission

The C-rich SiC
_x
with enhanced optical nonlinearity is employed to fabricate ring waveguides to perform picosecond optical switching of pulsed data streams under the wavelength conversion scheme. The C-rich SiC
_x
film after 60-minute annealing exhibits abundant graphite-like (sp
²
-like) C-C bonds resulting in the increase of its Kerr coefficient. Under transverse electric mode polarized pump-probe analysis, the continuous-wave transmittance comb spectrum of the C-rich SiCx-based ring waveguide shows a higher Q-factor than for transverse magnetic mode analysis. The red-shift of the transmission comb under a peak pumping power of 4.3 W increases from 0.12 to 0.14 nm as the nonlinear refractive index of the C-rich SiC
_x
increases from 1.37 × 10
^-12
to 2.38 × 10
^-12
cm
²
/W through increasing the annealing time from 0 to 60 min. The picosecond optical switching of pulsed bit data in the C-rich SiC
_x
ring waveguide provides an optimized extinction ratio (ER), a signal-to-noise ratio (SNR), and a bit-error rate (BER) of 8.1 dB, 8.2 dB, and 1.7 × 10
^-11
, respectively. After matching the probe wavelength with the red-shifted transmittance comb, the wavelength-converted data shows an inverted format with optimized ER, SNR, and BER of 7.9 dB, 8.1 dB, and 7.8 × 10
^-10
, respectively. The annealing regrown C-rich SiC
_x
can perform better nonlinear optical switching than reported so far for ultrafast data processing in photonic integrated circuits.