Summary: Measurement and plot of shotnoiseinterceptcurrent for PDA10CF.
Motivation:It is to measure the shot noise intercept current for PDA10CF.
Result: The final plot is attached here. The plot suggests that the value of shotnoiseintercept current is 0.21mA
Discussion:
The plot is for the measured data of Noise voltage (V/sqrt(Hz)) vs DCcurrent(A). The fitted plot to this measured data follows the noise equation
Vnoise = gdet* sqrt[ 2e (iDC+idet)] , where gdet= transimpedance of the PD in RF region as described in manual of PDA255 (i.e. 5e3 when it is not in Highimpedance region).
To get an approximate idea of the shot noise intercept current, we may follow the same procedure described in 7946
In the present case darknoise is 4.3e08 V/sqrt(Hz)
Therefore dark current(in2) ~dark noise voltage/RF transimpedance = 8.6pA/sqrt(Hz)
Therefore the approximate shot noise intercept current ~ (8.6/18)^2=0.22mA
This value matches well with the fitted data.
From PDA10CF manual, NEP=1.2e11W/sqrt(Hz) and responsivity~0.9A/W. Therefore the noise current level will be ~10pA.
