Raman based on-chip photonic quantizers for ADCs

Abstract

In this work, a model for an on-chip all-photonic analog to digital converter is proposed. Here, the underlying quantization technique is based on slicing the supercontinuum generated inside the highly nonlinear nanocrystal embedded slotted photonic crystal waveguide at specifically chosen wavelengths. It is shown that although both the broadening and splitting of the spectrum can be used for four level quantization, only broadening can be used for designing eight (or more) level quantization. The highly nonlinear device system makes the eight level quantization scheme incremental within a footprint of 50×20µm2, which can convert 0–11 mW analog optical power to respective quantization levels. Although both Kerr and stimulated Raman scattering (SRS) contribute to the generation of the supercontinuum, the giant SRS gain of the silicon nanocrystal essentially outweighs that of the Kerr, with, consequently, unprecedented miniaturization in both operating power and footprint.