The KPMC29 from Dexerials Corporation is an Si / InGaAs Two-tone Photodiode with an active area of 2.2 x 2.2 sq. mm (Si) and 0.86 x 0.86 sq. mm (InGaAs). To extend the wavelength range, Si photodiode which has the sensitivity to short-wavelength and InGaAs photodiode which has the sensitivity to long-wavelength are stacked on the same axis.