Photonic analog-to-digital converter based on wavelength sampling and quantizing

We propose a photonic analog-to-digital conversion scheme based on wavelength sampling and wavelength quantizing. The wavelength sampling is realized by using a high-speed electro-optical tunable filter that is controlled by analog electronic signal. The output wavelength of the optical filter is determined by the amplitude of the analog electronic signal. Different amplitude leads to the optical filter outputting different wavelength. The optical filter is based on long-period waveguide grating structure. An arrayed waveguide grating separates the different wavelength into different spatial channel to complete wavelength quantizing function. At the output of the spatial channels, a detector array is used to realize the coding function. The utilization of wavelength sampling and quantizing allows the ADC to achieve high resolution because the sampling and quantizing are carried out in the wavelength domain, which is immune to the intensity noise and jitter. Our ADC scheme is promising to achieve high-resolution and high-speed operation, and allows photonic integration.