Monolithic integration of an all-optical Mach-Zehnder demultiplexer using an asymmetric twin-waveguide structure

We demonstrate monolithic integration of a twin-waveguide Mach-Zehnder terahertz optical asymmetric demultiplexer (MZ-TOAD). The InGaAsP-InP device operates at 1.55 μm wavelength and has two semiconductor optical amplifiers in the asymmetric MZ interferometer configuration with a single control input and a built-in switching delay. A 28-ps full-width at half-maximum (FWHM) switching window with high contrast ratio for a range of control powers is obtained using a counter-propagating optical signal and control pulses.