Noise Performance of 1.3 µm InGaAsP Avalanche Photodiode at -190°C

The direct measurement of the noise performance for InGaAsP APD has for the first time been made at -190°C. The shot noise power measured at λ=0.633 µm varied as M 2.5 with avalanche multiplication M and the excess noise factor F ( M ) at M =10 was 3.5. Multiplication of 360 was obtained for the initial photocurrent of 2 µA. The effective ratio of hole-to-electron ionization coefficients at this temperature was estimated to be 0.05 from McIntyre's equation. It has been found that the characteristics of InGaAsP APDs are remarkably improved by decreasing the operation temperature. Therefore, applying cooled InGaAsP APDs to the low loss optical fiber transmission systems seems to be advantageous.