Equiangular spiral photonic crystal fiber for code synchronization in all-optical analog-to-digital conversion based on lumped time delay compensation scheme

In this paper, we propose a lumped time delay compensation scheme for the all-optical analog-to-digital conversion (ADC) based on soliton self-frequency shift (SSFS) and optical interconnection techniques. By inserting a length of equiangular spiral photonic crystal fiber (PCF) between quantization and coding modules, the time delay of quantized pulses can be compensated. Simulation results show that the pulses can be synchronized utilizing a span of equiangular spiral PCF with flat negative dispersion of −258.92 ps/(nm km)−258.92 ps/nm km in the wavelength range 1350 nm to 1675 nm. In addition, the amount of time delay and time error are analyzed, a maximum supportable sampling rate of 40 GSa/s is obtained.