III-V-on-silicon integrated micro - spectrometer for the 3 μm wavelength range.

A compact (1.2 mm²) fully integrated mid-IR spectrometer operating in the 3 μm wavelength range is presented. To our knowledge this is the longest wavelength integrated spectrometer operating in the important wavelength window for spectroscopy of organic compounds. The spectrometer is based on a silicon-on-insulator arrayed waveguide grating filter. An array of InAs_0.91Sb_0.09 p-i-n photodiodes is heterogeneously integrated on the spectrometers output grating couplers using adhesive bonding. The spectrometer insertion loss is less than 3 dB and the waveguide-referred responsivity of the integrated photodiodes at room temperature is 0.3 A/W.