Wavelength demulti/multiplexers with non-sinusoidal filtering characteristics composed of point-symmetrically connected Mach-Zehnder interferometers

Waveguide‐type wavelength demulti/multiplexers (WDM) with non‐sinusoidal filtering characteristics for optical communication systems are demonstrated using Mach‐Zehnder interferometers, (MZI) composed of point‐symmetrically connected MZI optical couplers. Three types of WDM, (1) a 1.3/1.55 μm wide‐band WDM, (2) a partially‐coupled 1.3/1.55 μm wide‐band WDM for fiber line testing, and (3) a 1.3 & 1.55/1.65 μm WDM were designed by appropriately setting the wavelength characteristics of the directional couplers and the path differences of the waveguide arms in the MZI‐WDMs. These WDMs were fabricated using silica‐based planar lightwave circuit technology, and the measured results were in good agreement with the designed characteristics. © 1998 Scripta Technica, Electron Comm Jpn Pt 2, 81(4): 19–28, 1998