GUIDED-WAVE SI1-XGEX SI WAVELENGTH DEMULTIPLEXER BASED ON MULTIMODE INTERFERENCE/

A novel multi-mode interference wavelength demultiplexer design in Si1 -xGex/Si for 1.3 and 1.55 mu m operation is investigated. From the the ory of large single-mode rib waveguides, the width of the rib waveguid es, height and etched depth were derived for a Ge content x = 0.04. Us ing the modal-propagation analysis method, the coupler length of the d evice is evaluated and the transmission characteristics are investigat ed. The results indicate that at the optimum coupler length of 1850 mu m and the optimum coupler width of 10 mu m, the contrasts achieved by this device are 40.6 dB and 39.9 dB at 1.3 and 1.55 mu m, respectivel y. Insertion loss is less than 0.1 dB at both wavelengths. (C) 1998 Pu blished by Elsevier Science B.V.