Optimal design of planar wavelength circuits based on Mach-Zehnder interferometers and their cascaded forms is presented with the wavelength dependence of the directional couplers considered. A simple approximate formula is presented to calculate quickly the wavelength-dependent phase difference for a directional coupler. By using this simple and effective formula and the genetic algorithm, a broadband coupler (1450-1650 nm) based on a Mach-Zehnder interferometer and a flat-top passband coarse wavelength division demultiplexer (with a channel spacing of 20 nm) based on cascaded Mach-Zehnder interferometers are optimally designed.
© 2005 IEEE
Qian Wang and Sailing He, "Optimal Design of Planar Wavelength Circuits Based on Mach-Zehnder Interferometers and Their Cascaded Forms," J. Lightwave Technol. 23, 1284- (2005)