Techniques for optical demultiplexing in high bit rate communication systems

Five standard configurations for optical demultiplexing of optical time domain multiplexed signals are compared. In terms of component usage and strobe signal requirements they are surprisingly equivalent. Both fiber loop and Mach-Zehnder configurations are studied. Fiber rings yield good stability, while configurations based on fiber Mach-Zehnder interferometers, in return, offer the possibility of add/drop demultiplexing. A new Mach-Zehnder configuration is proposed, which requires less optical components, only one strobe signal and has no optical losses (except from excess losses in couplers and splices). The sensitivity to power levels, fiber attenuation, signal and strobe wavelengths, etc., are analyzed and a preliminary design for a 100 to 5×20 Gb/s demultiplexer is suggested