We propose a simplified configuration of all-optical analog-to-digital (A/D) conversion using nonlinear optical loop mirrors (NOLMs). While the conventional scheme of such all-optical A/D conversion requires N encoders and N thresholders, for N-bit resolution, the proposed configuration realizes an N-bit resolution only using a single encoder and thresholder, based on a split-and-delay technique, in which the encoder and the thresholder operate more than N times as fast as the sampling speed. After discussing detailed design issues of the NOLM-based encoder with particular emphasis on the so-called counterpropagating effects, all-optical 3-bit A/D conversion at 10 GS/s is experimentally demonstrated using the proposed configuration.
© 2007 IEEE
Yuji Miyoshi, Kensuke Ikeda, Hideaki Tobioka, Takashi Inoue, Shu Namiki, and Ken-Ichi Kitayama, "All-Optical Analog-to-Digital Conversion Using Split-and-Delay Technique," J. Lightwave Technol. 25, 1339-1347 (2007)