All-optical XOR gate with optical feedback using highly Ge-doped nonlinear fiber and a terahertz optical asymmetric demultiplexer

We experimentally demonstrate an all-optical exclusive-OR (XOR) gate with optical feedback using a highly Ge-doped nonlinear fiber. The XOR is achieved based on cross-polarization rotation in nonlinear fiber, while the optical feedback employs a terahertz optical asymmetric demultiplexer (TOAD). The TOAD simultaneously cleans up the XOR output and converts the wavelength of the feedback signal to allow proper feedback operation. The performance of the all-optical XOR gate with optical feedback is studied through both experimental and simulation analysis. An open eye diagram of the XOR output in feedback mode is obtained experimentally, and a correct logic operation in feedback mode is proved through simulation. (C) 2011 Optical Society of America