OPTICAL FOLDING-FLASH ANALOG-TO-DIGITAL CONVERTER WITH ANALOG ENCODING

We describe an optically assisted folding-flash analog-to-digital converter. The periodic transfer function of the Mach-Zehnder interferometer is used to perform analog folding on the electronic signal to be quantized. A novel analog encoding scheme for efficient generation of gray code digital data is proposed. The new encoding scheme eliminates the requirement for interferometers with ultralow V-pi, which, so far, has hindered the development of such systems. The encoding concept is experimentally demonstrated through the use of LiNbO3 modulators. (C) 1995 Optical Society of America