Sensitivity of a receiver using GaInAsSb/AlGaAsSb SAM avalanche photodiode for long-wavelength optical communication systems in the mid-infrared spectral range

Low- noise avalanche photodiodes for the spectral range of 1.6-2.4 μm were created using the GaInAsSb solid solution in the absorption region and the wide-gap GaAlX(As)Sb alloy of resonant composition (x=0.04) in the multiplication region. This APD has a very high ratio of ionization coefficients, β/α>30 and low excess noise factor, F~1.6 (M=10). The sensitivity of a receiver for longwavelength communication (λ=1.6-2.5 μm) based on GaInAsSb/AlGa(As)Sb SAM APD is reported. The sensitivity for a direct detection receiver using the SAM APD was calculated according to the treatment of Personick at bit rate B=500 Mbit/s. The dependence of minimum detectable power η on multiplication M for the SAM APD for the wavelength λ=2.1 μm was calculated and compared with one for a standard Ge APD operating at λ=1.55 μm. A minimum detectable power level η = -42.3 dBm at Mopt=34-39 and η=-41.8 dBm at Mopt=10 of the receivers with the GaInAsSb/GaAl(As)Sb SAM APD and the Ge APD, respectively were obtained. These results demonstrate the potential of an optical receiver with the GaInAsSb/GaAl(As)Sb SAM APD for use in mid-IR wavelength optical communication system as well as of great interest for their potential applications in laser range-finding system.