Demonstration of silicon-on-insulator mid-infrared spectrometers operating at 3.8 um

The design and characterization of silicon-on-insulator mid-infrared spectrometers operating at 3.8µm is reported. The devices are fabricated on 200mm SOI wafers in a CMOS pilot line. Both arrayed waveguide grating structures and planar concave grating structures were designed and tested. Low insertion loss (1.5-2.5dB) and good crosstalk characteristics (15-20dB) are demonstrated, together with waveguide propagation losses in the range of 3 to 6dB/cm